|Spinal cord injury; Sur1-Trpm4 Channel; Glibenclamide;
|Spinal cord injury (SCI) is a major unsolved challenge in medicine.
Worldwide, the incidence of SCI ranges from 10 to 83 per million
people per year, with half of these patients suffering a complete lesion
and one-third becoming tetraplegic . In the United States, 250,000
people live with SCI and 11,000 new cases are added yearly. At present,
little can be done to undo or repair the initial damage to spinal cord
tissues, but great hope lies in reducing secondary injury processes
triggered by the trauma that increase the damage and worsen clinical
|Impact trauma to the spinal cord shears blood vessels, causing
an immediate ‘primary hemorrhage’. The volume of the primary
hemorrhage is directly related to the severity of the impact .
Numerous secondary injury mechanisms are then initiated, on a
time scale from seconds to days, with microvascular dysfunction
and endothelial cell loss being among the earliest pathophysiological
responses observed . During the hours following trauma, the region
of hemorrhage enlarges progressively, with delayed or ‘secondary
hemorrhage’ adding to the primary hemorrhage, and effectively
doubling its volume. The process responsible for the secondary
hemorrhage that results in early expansion of the hemorrhagic lesion is
termed ‘progressive hemorrhagic necrosis’ (PHN). PHN is a dynamic
process of autodestruction whose molecular underpinnings are only
now beginning to be elucidated.
|PHN results from the delayed, progressive, catastrophic failure
of the structural integrity of capillaries . As capillaries in the
vicinity of the lesion fail, numerous microhemorrhages (petechial
hemorrhages) form and coalesce, resulting in hemorrhagic lesion
expansion. This dynamic process wherein the hemorrhagic contusion
enlarges progressively results in the autodestruction of spinal cord
tissues [4-8]. PHN is particularly damaging because it expands the
volume of neural tissue destroyed by the primary injury. The capillary
dysfunction implicit with PHN causes tissue ischemia and hypoxia ,
and the extravasated blood resulting from PHN is toxic to CNS cells,
especially to the myelin-forming oligodendrocytes of white matter ,
resulting in further injury to neural tissues due to oxidative stress, lipid peroxidation and inflammation. Together, these processes render PHN
one of the most destructive mechanisms of secondary injury identified
following trauma to the spinal cord.
|Early lesion expansion due to PHN was described more than 4
decades ago in an animal model of SCI , but has not been well
characterized in humans, due largely to the enormous medical and
technical challenges that are incurred when performing magnetic
resonance imaging (MRI) on severely injured, often medically unstable
patients early after trauma. Notwithstanding such difficulties, emerging
evidence supports the concept of lesion expansion in humans with SCI
[12,13], making this mechanism of secondary injury highly relevant
clinically. The importance of these observations lies in the hope that, if
early expansion of the hemorrhagic lesion can be halted, patients with
acute SCI may suffer the least overall injury.
|Progressive Hemorrhagic Necrosis - A Unique Phenotype
of Capillary Fragmentation
|Early lesion expansion
|Histological and MRI studies on animal models of SCI have
shown that early expansion of a hemorrhagic contusion is a common
feature following trauma to the spinal cord. To our knowledge, the
earliest study (weight drop; midline, lower thoracic / upper lumbar)
quantifying early lesion expansion reported that, on H&E-stained
sections, intramedullary hemorrhages involved an aggregate of 11% of
the spinal cord area at the level of maximal bleeding immediately after
trauma, and that this increased 2.5-fold to 28% after 8 hr . In our
previous study (weight drop; lateral C7), we reported a 2-fold increase in the amount of extravasated blood in tissues from the epicenter during
the first 12 hr after trauma . In an MRI study (0.5 mm compression
for 30 msec; T7), the T2 lesion volume was found to expand˜1.5-fold
over 5.5 hr . In our recent study (weight drop; lateral C7) based
on MRI T2 lesion volumes and measurements of hemorrhagic lesion
areas, we found a 2-2.5-fold increase in the hemorrhagic contusion
that takes place during the first 24 hr after blunt impact trauma to the
spinal cord .
|Together, the animal studies from different laboratories and
from different epochs, using different methods to induce trauma,
and different approaches to document lesion expansion, establish the
existence of significant lesion expansion during the early hours after
blunt impact trauma to the spinal cord.
|The secondary hemorrhage that develops following the trauma
arises from individual, discrete microscopic (petechial) hemorrhages
that appear first near the site of injury then in more distant areas
rostrally and caudally, mostly in the gray matter [4,16]. As microscopic
hemorrhages form and coalesce, the lesion gradually expands, with
a characteristic region of hemorrhage that ‘caps’ the advancing front
of the lesion [6,8]. A small hemorrhagic lesion that initially involves
primarily the capillary-rich gray matter enlarges several-fold during
3-24 hr after injury (Figure 1A) [11,17].
|The formation of discrete microscopic hemorrhages is linked to the
delayed progressive catastrophic failure of the structural integrity of
capillaries. In static histological tissue sections, vimentin- or CD-31-
positive capillaries appear foreshortened, as small segments of nearly the
same length and width, a phenomenon termed ‘capillary fragmentation’ (Figure 2A) [4,18-20]. In some cases, including in humans (Figure 1B),
extravasated erythrocytes are observed near microvessels that appear
broken . The presence of fragmented capillaries in the penumbra of
injury is a pathognomonic feature of PHN. As discussed below, when
the molecular antecedent of PHN is blocked, capillary fragmentation is
absent (Figure 2B,2C,2D), early expansion of the hemorrhagic lesion
is halted, and secondary hemorrhage is prevented, i.e., the volume
of extravasated blood measured at 24 hr is nearly the same as in the
primary hemorrhage, measured 15 min after trauma (Figure 1A) [4,15].
|Expression of the Sur1-Trpm4 channel in SCI
|Accumulating evidence indicates that the molecular antecedent
of PHN is the Sur1-Trpm4 channel. This ion channel is not expressed
constitutively, but is transcriptionally upregulated in endothelial
and other cells after spinal cord trauma. In mice, rats and humans,
upregulation of the regulatory subunit of the channel, Sur1 protein and
its mRNA (Abcc8), has been demonstrated in microvessels, neurons
and white matter using immunohistochemistry, immunoblot analysis, and in situ hybridization [4,19,21]. In mice and rats, upregulation
of the pore forming subunit of the channel, Trpm4 protein and its
mRNA (Trpm4), has been shown in microvessels and neurons using
immunohistochemistry, quantitative RT-PCR and in situ hybridization
|Co-association of the regulatory and pore-forming subunits to
form functional Sur1-Trpm4 channels recently was shown using
Förster resonance energy transfer (FRET) imaging microscopy and coimmunoprecipitation
. Antibody-based FRET was used to evaluate
rat spinal cord tissues before and after injury. In uninjured spinal cord,
Sur1 and Trpm4 immunolabeling was minimal [4,18,19], and FRET
signals were absent. However, 24 hours after spinal cord trauma, Sur1
and Trpm4 immunolabeling was prominent, immunolabeling for Sur1 and Trpm4 co-localized, and FRET signals were detected in various
cellular structures, including microvessels (Figure 3A).
|In the same report , co-immunoprecipitation experiments
showed abundant Sur1 and Trpm4 after spinal cord trauma. Coimmunoprecipitation
using anti-Trpm4 antibody yielded Sur1, and
co-immunoprecipitation using anti-Sur1 antibody yielded Trpm4.
Importantly, coimmunoprecipitation using anti-Sur1 antibody yielded
Trpm4 only after spinal cord injury, not in uninjured spinal cord
(Figure 3B). Together, these findings with co-immunoprecipitation
and FRET demonstrate that Sur1 and Trpm4 co-assemble in vivo to
form functional Sur1-Trpm4 channels following spinal cord injury.
|Progressive hemorrhagic necrosis - role of the Sur1-
|Various cell types exhibit de novo upregulation of Sur1-Trpm4
channels after spinal cord trauma, but secondary hemorrhage due to
PHN is linked specifically to channel upregulation in microvessels
[4,18,19]. Sur1-Trpm4 channels have been shown to be responsible
for the necrotic death of endothelial cells that results in delayed
fragmentation of capillaries and formation of microhemorrhages.
|Evidence for involvement of the Sur1-Trpm4 channel in PHN
comes from an analysis of the effects of gene deletion, gene suppression,
or pharmacological inhibition of the two channel subunits, Sur1 and
Trpm4. Remarkably, interfering with the function of either of the
two channel subunits yields exactly the same effect histologically and
|The phenotype observed after spinal cord injury in Abcc8-/- mice
is exactly the same as in Trpm4-/- mice [18,19]. Both genotypes show
the same post-SCI phenotype, and both are equally protected from
PHN. Both genotypes show minimal secondary hemorrhage and lesion
expansion, and the absence of capillary fragmentation, the hallmark
of PHN. In a model of unilateral trauma (T9), functional outcomes,
measured using the Basso mouse scale, and lesion volumes at 1 week
are significantly better in both knockout mice compared to wild type
|Similarly, the phenotype observed after spinal cord injury in rats
administered antisense oligodeoxynucleotide (AS-ODN) targeting
Abcc8 is exactly the same as in rats administered AS-ODN targeting
Trpm4. Both show the same phenotype, and both are equally protected
from PHN. Both show minimal secondary hemorrhage and lesion
expansion, and the absence of capillary fragmentation, the hallmark
of PHN. In a model of unilateral trauma (C7), functional outcomes,
measured using the Basso, Beattie, Bresnahan scale, and lesion volumes
at 6 weeks are significantly better in rats administered either AS-ODN
compared to rats administered scrambled ODN.
|Pharmacological blockade of Sur1
|Pharmacological blockade of Sur1 has been studied using
two highly selective agents, glibenclamide and repaglinide .
Glibenclamide is a second generation sulfonylurea drug that binds to
Sur1 with subnanomolar or nanomolar affinity (0.4-4.0 nM)  and
potently inhibits the Sur1-Trpm4 channel (EC50 = 48 nM) [21,23].
Repaglinide is a member of a distinct class of insulin secretagogues
that are structurally unrelated to sulphonylureas and whose
binding site on Sur1 may differ from that of sulfonylureas . Like
glibenclamide, repaglinide produces high-affinity block of both native
and recombinant β-cell KATP channels (IC50 = 0.9-7 nM), and shows
higher potency in inhibiting pancreatic Sur1-regulated KATP channels
than cardiovascular Sur2-regulated channels .
|In rat models of SCI, glibenclamide and repaglinide exert beneficial
effects that exhibit the signature features of inhibition of PHN. Rats
treated with either glibenclamide or repaglinide show minimal
secondary hemorrhage and lesion expansion, and the absence of
capillary fragmentation, the hallmark of PHN (Figure 2C,2D). In
models of unilateral or bilateral trauma (C7), functional outcomes,
measured using the Basso, Beattie, Bresnahan scale, and lesion
volumes at 6 weeks are significantly better in rats administered either
compound, compared to controls [4,26]. Notably, direct comparison
between glibenclamide and AS-ODN directed against Abcc8 shows
equivalent effects in rats, in terms of functional outcomes and lesion
volumes at 6 weeks, with neither compound exhibiting any observable
|In 4 separate series on rats from our laboratory [4,15,19,26], and
in one series from an independent laboratory , glibenclamide
treatment beginning shortly after trauma was found to be highly
effective in reducing lesion size and improving neurological function.
In a 6th series of rats, treatment at the clinically more relevant time of
3 hr after trauma also was found to be highly beneficial . As might
be expected, the magnitude of the benefit observed with glibenclamide
depends on the magnitude of the primary injury , but all studies
to date examining functional outcome and lesion size at 6 weeks have
demonstrated a significant treatment effect, regardless of the initial
|Pharmacological blockade of Trpm4
|At present, specific pharmacological blockade of Trpm4 is not
feasible, possibly because of structural similarities of Trpm4 to other
ion channels. Drugs that block Trpm4 are pleotropic, affecting other
molecular targets. To date, pharmacological blockade of Trpm4 in SCI
models has been pursued using flufenamic acid or riluzole. Flufenamic
acid is an open-channel blocker of Trpm4 and of numerous other
nonselective cationic channels, a widely expressed, heterogeneous
family of channels of diverse molecular origins . The benzothiazole,
riluzole, recently was shown to block Trpm4 currents (IC50 = 31 μM)
, but it also blocks other molecules. Riluzole was first proposed
to inhibit glutamate release [29-32], thus protecting neurons from
excitotoxic damage [33,34]. At micromolar concentrations (IC50,
3-10 μM), riluzole is considered to be a relatively selective blocker of
‘persistent sodium currents’ in cardiac myocytes and CNS neurons,
including spinal cord neurons, where the molecular identity of the
channel(s) responsible for these currents is not known [35-40].
|In rat models of SCI, flufenamic acid and riluzole exert beneficial
effects that exhibit the signature features of inhibition of PHN. The
effects of flufenamic acid and riluzole are qualitatively similar to those
of glibenclamide, including reduced necrotic lesion volumes and better
functional outcomes [4,20,41,42]. Although a number of molecular
targets could be involved, it is striking that both compounds show the
same phenotype as gene suppression of Sur1  or gene suppression
of Trpm4 . Rats treated with either flufenamic acid or riluzole show
minimal secondary hemorrhage and lesion expansion, and the absence
of capillary fragmentation, the hallmark of PHN (Figure 2B,2D). In a
model of unilateral trauma (C7), functional outcomes, measured using
the Basso, Beattie, Bresnahan scale, and lesion volumes at 6 weeks are
significantly better in rats administered either compound, compared
to controls. To our knowledge, the inhibition of other molecular
targets potentially affected by flufenamic acid and riluzole would not
be expected to manifest the unique phenotype of inhibiting capillary
fragmentation, since this effect is specific for the Sur1-Trpm4 channel.
|Glibenclamide vs. riluzole
|Riluzole has been found to be efficacious in preclinical models of SCI
[20,43,44], may have a beneficial effect on motor outcome in cervical
SCI, as recently reported in a small open-label Phase I clinical trial ,
and currently is the only drug that is anticipated for study in a Phase II
clinical trial of acute SCI (Clinical Trials.gov identifier, NCT01597518).
In the anticipated clinical trial, riluzole will be administered enterally
at a dose of 2 × 100 mg the first 24 hours followed by 2 × 50 mg for the
following 13 days after injury.
|A recent preclinical study using a rat model of SCI, which was
so severe as to have attendant mortality, compared treatment with
riluzole (2.5 mg/kg IP every 12 hr × 1 week) vs. glibenclamide (10
μg/kg IP loading dose plus 200 ng/hr continuous subcutaneous
infusion × 1 week), starting 3 hr after trauma . This study found
that glibenclamide is superior to riluzole in terms of both toxicity and
efficacy. During the acute phase after trauma, both drugs reduced
capillary fragmentation and PHN (Figure 2), and both prevented
death. At 6 weeks, modified (unilateral) Basso, Beattie, Bresnahan
locomotor scores were similar, but measures of complex function
(grip strength, rearing, accelerating rotarod) and tissue sparing were
significantly better with glibenclamide than with riluzole. Note that in
this preclinical study, riluzole was administered parenterally, which
yields better bioavailability than enteral administration, and it was
administered at a higher dose (on a ‘per kilogram’ basis), compared to
the dose proposed for the anticipated clinical trial.
|Apart from inhibiting PHN via blockade of Sur1-Trpm4, riluzole
exerts other biological effects. At micromolar concentrations (IC50,
3-10 μM), riluzole blocks ‘persistent sodium currents’ in cardiac
myocytes and CNS neurons, including spinal cord neurons, where the
molecular identity of the channel(s) responsible for these currents is not
known [35-40]. Riluzole blocks several molecularly identified potassium
channels [46-50], and calcium channels [51-53]. Riluzole also inhibits
glutamate release [29,30-32], and it interacts with ?-aminobutyric acid
A and glycine receptor-activated channels [30,54-56]. Riluzole also
directly binds to and inhibits protein kinase C . The role of any of
these molecular targets in PHN is not known. It is possible that riluzole
exerts part of its salutary effects via one these mechanisms, in addition
to Sur1-Trpm4 inhibition, but specific involvement of any of these
mechanisms has not been shown. Notably, involvement of glutamate
antagonism is now thought to be unlikely [58,59].
|A high degree of non-specificity in a drug generally is undesirable,
since this can lead to untoward side-effects and undue toxicity. Nonspecificity
may account for the acute toxicity observed with high doses
of riluzole, which includes somnolence, coma or a moribund state
[60,61]. In addition, riluzole exhibits an unusual, dose-limiting CNS
toxicity that is present only in CNS trauma, not in uninjured controls:
mortality rates of 0%, 8% and 70% are observed with 4, 6 and 8 mg/kg
IP every 12 hr, respectively, in rats after SCI, whereas these doses are
well tolerated in normal uninjured rats .
|Drug specificity is less problematic with glibenclamide. Apart from
high-potency block of Sur1-Trpm4 channels (EC50 = 48 nM) [21,23],
glibenclamide also blocks Sur1-regulated KATP channels in pancreatic
β cells . However, at the doses used in CNS ischemia and trauma,
the potential consequence of block of pancreatic KATP channels -
hypoglycemia - is not observed; infusion of 200 ng/hr of glibenclamide
in rats has a minimal effect on serum glucose [4,63,64]. Sur2-regulated
KATP channels in cardiac and smooth muscle cells are less sensitive
to block by glibenclamide, by a factor of 10 times or more [62,65]. Other ATP-binding cassette proteins of the ABC gene family may be
blocked by glibenclamide, but only at micromolar concentrations ,
far greater than the concentrations acheived with infusion of 200 ng/
hr in rats.
|In the 6 series of rats reported to date on glibenclamide in SCI (see
above), the drug was delivered by constant subcutaneous infusion. From
a pharmacokinetic perspective, cutaneous delivery of glibenclamide
is highly effective for maintaining steady plasma levels, is superior to
enteral administration, and appears to be equivalent to intravenous (IV)
administration . Constant subcutaneous infusion of glibenclamide
was used in the preclinical studies as a convenient alternative to constant
IV infusion, as is used with injectable glibenclamide (RP-1127) in
clinical trials for other CNS indications (ClinicalTrials.gov identifiers:
NCT01454154; NCT01268683; NCT01794182). In the animal studies,
no clinically relevant hypoglycemia or other toxicity has been detected
with infusions of 200 ng/hr [4,63,64] or 400 ng/hr . In a Phase I
trial of RP-1127 in 16 normal subjects (ClinicalTrials.gov identifier:
NCT01132703), a 3-day IV infusion (125 μg/hr) produced no clinically
significant hypoglycemia or other serious adverse event (S. Jacobson,
|From the perspective of efficacy in targeting the Sur1-Trpm4 channel for reducing PHN, as well as from the perspective of safety and
tolerability, glibenclamide may be a better choice than riluzole for the
treatment of acute spinal cord injury.
|Each year, traumatic injury to the spinal cord devastates the
lives of thousands of people worldwide. Short of preventing primary
injury, the best hope for reducing the life-long impact of SCI rests
with decreasing the secondary injury that results from PHN occurring
during the acute phase after trauma. Although progress has been made
in axonal and dendritic remodeling, cell replacement therapies, and
rehabilitation, it is generally acknowledged that these treatments work
best when administered to patients with the smallest possible lesion. To
date, clinical trials with agents such as methylprednisolone (NASCIS
II and III) and GM-1 ganglioside have shown risk-benefit profiles
that are not sufficiently favorable to warrant routine clinical use, and
other therapies intended for treatment in the acute phase have yet to
be proven .
|As reviewed here, emerging data indicate that in the earliest
phase after trauma, the Sur1-Trpm4 channel is newly upregulated in
the penumbra of injury, and that the expression of this channel in
penumbral microvessels is integral to the subsequent development
of PHN, which is responsible to early expansion of the hemorrhagic
lesion. Also, as reviewed here, considerable data have now been
published showing that targeting this channel by gene deletion, by
gene suppression, or by pharmacological inhibition of either of the
two channel subunits yields exactly the same effect histologically and
functionally, and the exactly same unique, pathognomonic phenotype-the prevention of capillary fragmentation in the penumbra. The
possibility of inhibiting the Sur1-Trpm4 channel using glibenclamide
is a promising strategy for ameliorating the devastating sequelae of
spinal cord trauma in humans.
|This work was supported by grants to JMS from the Veterans Administration
(Baltimore), the National Institute of Neurological Disorders and Stroke (NINDS)
(NS060801), and the Department of the Army (W81XWH 1010898); to VG from
|Conflict of interest statement
|JMS holds a US patent (#7,872,048), “Methods for treating spinal cord injury
with a compound that inhibits a NC (Ca-ATP) channel”. JMS is a member of
the scientific advisory board and holds shares in Remedy Pharmaceuticals. No
support, direct or indirect, was provided to JMS, or for this project, by Remedy
Pharmaceuticals. All other authors declare no conflict of interest.
- Wyndaele M, Wyndaele JJ (2006) Incidence, prevalence and epidemiology of spinal cord injury: what learns a worldwide literature survey? Spinal Cord 44: 523-529.
- Mautes AE, Weinzierl MR, Donovan F, Noble LJ (2000) Vascular events after spinal cord injury: contribution to secondary pathogenesis. Phys Ther 80: 673-687.
- Fassbender JM, Whittemore SR, Hagg T (2011) Targeting microvasculature for neuroprotection after SCI. Neurotherapeutics 8: 240-251.
- Simard JM, Tsymbalyuk O, Ivanov A, Ivanova S, Bhatta S, et al. (2007) Endothelial sulfonylurea receptor 1-regulated NC Ca-ATP channels mediate progressive hemorrhagic necrosis following spinal cord injury. J Clin Invest 117: 2105-2113.
- Noble LJ, Wrathall JR (1989) Correlative analyses of lesion development and functional status after graded spinal cord contusive injuries in the rat. Exp Neurol 103: 34-40.
- Zhang Z, Krebs CJ, Guth L (1997) Experimental analysis of progressive necrosis after spinal cord trauma in the rat: etiological role of the inflammatory response. Exp Neurol 143: 141-152.
- Steward O, Schauwecker PE, Guth L, Zhang Z, Fujiki M, et al. (1999) Genetic approaches to neurotrauma research: opportunities and potential pitfalls of murine models. Exp Neurol 157: 19-42.
- Guth L, Zhang Z, Steward O (1999) The unique histopathological responses of the injured spinal cord. Implications for neuroprotective therapy. Ann N Y Acad Sci 890: 366-384.
- Tator CH, Koyanagi I (1997) Vascular mechanisms in the pathophysiology of human spinal cord injury. J Neurosurg 86: 483-492.
- Regan RF, Guo Y (1998) Toxic effect of hemoglobin on spinal cord neurons in culture. J Neurotrauma 15: 645-653.
- Balentine JD (1978) Pathology of experimental spinal cord trauma. I. The necrotic lesion as a function of vascular injury. Lab Invest 39: 236-253.
- Fleming JC, Norenberg MD, Ramsay DA, Dekaban GA, Marcillo AE, et al. (2006) The cellular inflammatory response in human spinal cords after injury. Brain 129: 3249-3269.
- Aarabi B, Simard JM, Kufera JA, Alexander M, Zacherl KM, et al. (2012) Intramedullary lesion expansion on magnetic resonance imaging in patients with motor complete cervical spinal cord injury. J Neurosurg Spine 17: 243-250.
- Bilgen M, Abbe R, Liu SJ, Narayana PA (2000) Spatial and temporal evolution of hemorrhage in the hyperacute phase of experimental spinal cord injury: in vivo magnetic resonance imaging. Magn Reson Med 43: 594-600.
- Simard JM, Popovich PG, Tsymbalyuk O, Caridi J, Gullapalli RP, et al. (2013) MRI evidence that glibenclamide reduces lesion expansion in a rat model of spinal cord injury. Spinal Cord : in press.
- Kawata K, Morimoto T, Ohashi T, Tsujimoto S, Hoshida T, et al. (1993) [Experimental study of acute spinal cord injury: a study of spinal blood flow]. No Shinkei Geka 21: 239-245.
- Iizuka H, Yamamoto H, Iwasaki Y, Yamamoto T, Konno H (1987) Evolution of tissue damage in compressive spinal cord injury in rats. J Neurosurg 66: 595-603.
- Gerzanich V, Woo SK, Vennekens R, Tsymbalyuk O, Ivanova S, et al. (2009) De novo expression of Trpm4 initiates secondary hemorrhage in spinal cord injury. Nat Med 15: 185-191.
- Simard JM, Woo SK, Norenberg MD, Tosun C, Chen Z, et al. (2010) Brief suppression of Abcc8 prevents autodestruction of spinal cord after trauma. Sci Transl Med 2: 28ra29.
- Simard JM, Tsymbalyuk O, Keledjian K, Ivanov A, Ivanova S, et al. (2012) Comparative effects of glibenclamide and riluzole in a rat model of severe cervical spinal cord injury. Exp Neurol 233: 566-574.
- Woo SK, Kwon MS, Ivanov A, Gerzanich V, Simard JM (2013) The sulfonylurea receptor 1 (Sur1)-transient receptor potential melastatin 4 (Trpm4) channel. J Biol Chem 288: 3655-3667.
- Aguilar-Bryan L, Nelson DA, Vu QA, Humphrey MB, Boyd AE 3rd (1990) Photoaffinity labeling and partial purification of the beta cell sulfonylurea receptor using a novel, biologically active glyburide analog. J Biol Chem 265: 8218-8224.
- Chen M, Dong Y, Simard JM (2003) Functional coupling between sulfonylurea receptor type 1 and a nonselective cation channel in reactive astrocytes from adult rat brain. J Neurosci 23: 8568-8577.
- Hansen AM, Christensen IT, Hansen JB, Carr RD, Ashcroft FM, et al. (2002) Differential interactions of nateglinide and repaglinide on the human beta-cell sulphonylurea receptor 1. Diabetes 51: 2789-2795.
- Stephan D, Winkler M, Kühner P, Russ U, Quast U (2006) Selectivity of repaglinide and glibenclamide for the pancreatic over the cardiovascular K(ATP) channels. Diabetologia 49: 2039-2048.
- Simard JM, Popovich PG, Tsymbalyuk O, Gerzanich V (2012) Spinal cord injury with unilateral versus bilateral primary hemorrhage--effects of glibenclamide. Exp Neurol 233: 829-835.
- Popovich PG, Lemeshow S, Gensel JC, Tovar CA (2012) Independent evaluation of the effects of glibenclamide on reducing progressive hemorrhagic necrosis after cervical spinal cord injury. Exp Neurol 233: 615-622.
- Peña F, Ordaz B (2008) Non-selective cation channel blockers: potential use in nervous system basic research and therapeutics. Mini Rev Med Chem 8: 812-819.
- Benavides J, Camelin JC, Mitrani N, Flamand F, Uzan A, et al. (1985) 2-Amino-6-trifluoromethoxy benzothiazole, a possible antagonist of excitatory amino acid neurotransmission--II. Biochemical properties. Neuropharmacology 24: 1085-1092.
- Martin D, Thompson MA, Nadler JV (1993) The neuroprotective agent riluzole inhibits release of glutamate and aspartate from slices of hippocampal area CA1. Eur J Pharmacol 250: 473-476.
- Zona C, Cavalcanti S, De Sarro G, Siniscalchi A, Marchetti C, et al. (2002) Kainate-induced currents in rat cortical neurons in culture are modulated by riluzole. Synapse 43: 244-251.
- Coderre TJ, Kumar N, Lefebvre CD, Yu JS (2007) A comparison of the glutamate release inhibition and anti-allodynic effects of gabapentin, lamotrigine, and riluzole in a model of neuropathic pain. J Neurochem 100: 1289-1299.
- Azbill RD, Mu X, Springer JE (2000) Riluzole increases high-affinity glutamate uptake in rat spinal cord synaptosomes. Brain Res 871: 175-180.
- Dunlop J, Beal McIlvain H, She Y, Howland DS (2003) Impaired spinal cord glutamate transport capacity and reduced sensitivity to riluzole in a transgenic superoxide dismutase mutant rat model of amyotrophic lateral sclerosis. J Neurosci 23: 1688-1696.
- Urbani A, Belluzzi O (2000) Riluzole inhibits the persistent sodium current in mammalian CNS neurons. Eur J Neurosci 12: 3567-3574.
- Tazerart S, Viemari JC, Darbon P, Vinay L, Brocard F (2007) Contribution of persistent sodium current to locomotor pattern generation in neonatal rats. J Neurophysiol 98: 613-628.
- Lamanauskas N, Nistri A (2008) Riluzole blocks persistent Na+ and Ca2+ currents and modulates release of glutamate via presynaptic NMDA receptors on neonatal rat hypoglossal motoneurons in vitro. Eur J Neurosci 27: 2501-2514.
- Lamas JA, Romero M, Reboreda A, Sánchez E, Ribeiro SJ (2009) A riluzole- and valproate-sensitive persistent sodium current contributes to the resting membrane potential and increases the excitability of sympathetic neurones. Pflugers Arch 458: 589-599.
- Weiss SM, Saint DA (2010) The persistent sodium current blocker riluzole is antiarrhythmic and anti-ischaemic in a pig model of acute myocardial infarction. PLoS One 5: e14103.
- Xie RG, Zheng DW, Xing JL, Zhang XJ, Song Y, et al. (2011) Blockade of persistent sodium currents contributes to the riluzole-induced inhibition of spontaneous activity and oscillations in injured DRG neurons. PLoS One 6: e18681.
- Ates O, Cayli SR, Gurses I, Turkoz Y, Tarim O, et al. (2007) Comparative neuroprotective effect of sodium channel blockers after experimental spinal cord injury. J Clin Neurosci 14: 658-665.
- Schwartz G, Fehlings MG (2001) Evaluation of the neuroprotective effects of sodium channel blockers after spinal cord injury: improved behavioral and neuroanatomical recovery with riluzole. J Neurosurg 94: 245-256.
- Wahl F, Stutzmann JM (1999) Neuroprotective effects of riluzole in neurotrauma models: a review. Acta Neurochir Suppl 73: 103-110.
- Wu Y, Satkunendrarajah K, Teng Y, Chow DS, Buttigieg J, et al. (2013) Delayed post-injury administration of riluzole is neuroprotective in a preclinical rodent model of cervical spinal cord injury. J Neurotrauma 30: 441-452.
- Grossman RG, Fehlings M, Frankowski R, Burau KD, Chow D, et al. (2013) A Prospective Multicenter Phase 1 Matched Comparison Group Trial of Safety, Pharmacokinetics, and Preliminary Efficacy of Riluzole in Patients with Traumatic Spinal Cord Injury. J Neurotrauma .
- Zona C, Siniscalchi A, Mercuri NB, Bernardi G (1998) Riluzole interacts with voltage-activated sodium and potassium currents in cultured rat cortical neurons. Neuroscience 85: 931-938.
- Duprat F, Lesage F, Patel AJ, Fink M, Romey G, et al. (2000) The neuroprotective agent riluzole activates the two P domain K(+) channels TREK-1 and TRAAK. Mol Pharmacol 57: 906-912.
- Cao YJ, Dreixler JC, Couey JJ, Houamed KM (2002) Modulation of recombinant and native neuronal SK channels by the neuroprotective drug riluzole. Eur J Pharmacol 449: 47-54.
- Ahn HS, Choi JS, Choi BH, Kim MJ, Rhie DJ, et al. (2005) Inhibition of the cloned delayed rectifier K+ channels, Kv1.5 and Kv3.1, by riluzole. Neuroscience 133: 1007-1019.
- Xu L, Enyeart JA, Enyeart JJ (2001) Neuroprotective agent riluzole dramatically slows inactivation of Kv1.4 potassium channels by a voltage-dependent oxidative mechanism. J Pharmacol Exp Ther 299: 227-237.
- Huang CS, Song JH, Nagata K, Yeh JZ, Narahashi T (1997) Effects of the neuroprotective agent riluzole on the high voltage-activated calcium channels of rat dorsal root ganglion neurons. J Pharmacol Exp Ther 282: 1280-1290.
- Siniscalchi A, Bonci A, Mercuri NB, Bernardi G (1997) Effects of riluzole on rat cortical neurones: an in vitro electrophysiological study. Br J Pharmacol 120: 225-230.
- Stefani A, Spadoni F, Bernardi G (1997) Differential inhibition by riluzole, lamotrigine, and phenytoin of sodium and calcium currents in cortical neurons: implications for neuroprotective strategies. Exp Neurol 147: 115-122.
- Umemiya M, Berger AJ (1995) Inhibition by riluzole of glycinergic postsynaptic currents in rat hypoglossal motoneurones. Br J Pharmacol 116: 3227-3230.
- Mohammadi B, Krampfl K, Moschref H, Dengler R, Bufler J (2001) Interaction of the neuroprotective drug riluzole with GABA(A) and glycine receptor channels. Eur J Pharmacol 415: 135-140.
- He Y, Benz A, Fu T, Wang M, Covey DF, et al. (2002) Neuroprotective agent riluzole potentiates postsynaptic GABA(A) receptor function. Neuropharmacology 42: 199-209.
- Noh KM, Hwang JY, Shin HC, Koh JY (2000) A novel neuroprotective mechanism of riluzole: direct inhibition of protein kinase C. Neurobiol Dis 7: 375-383.
- Lips J, de Haan P, Bodewits P, Vanicky I, Dzoljic M, et al. (2000) Neuroprotective effects of riluzole and ketamine during transient spinal cord ischemia in the rabbit. Anesthesiology 93: 1303-1311.
- McAdoo DJ, Hughes MG, Nie L, Shah B, Clifton C, et al. (2005) The effect of glutamate receptor blockers on glutamate release following spinal cord injury. Lack of evidence for an ongoing feedback cascade of damage --> glutamate release --> damage --> glutamate release --> etc. Brain Res 1038: 92-99.
- Mantz J, Chéramy A, Thierry AM, Glowinski J, Desmonts JM (1992) Anesthetic properties of riluzole (54274 RP), a new inhibitor of glutamate neurotransmission. Anesthesiology 76: 844-848.
- Kitzman PH (2009) Effectiveness of riluzole in suppressing spasticity in the spinal cord injured rat. Neurosci Lett 455: 150-153.
- Bryan J, Aguilar-Bryan L (1999) Sulfonylurea receptors: ABC transporters that regulate ATP-sensitive K(+) channels. Biochim Biophys Acta 1461: 285-303.
- Simard JM, Yurovsky V, Tsymbalyuk N, Melnichenko L, Ivanova S, et al. (2009) Protective effect of delayed treatment with low-dose glibenclamide in three models of ischemic stroke. Stroke 40: 604-609.
- Barthel W, Markwardt F (1975) Aggregation of blood platelets by adrenaline and its uptake. Biochem Pharmacol 24: 1903-1904.
- Simard JM, Woo SK, Bhatta S, Gerzanich V (2008) Drugs acting on SUR1 to treat CNS ischemia and trauma. Curr Opin Pharmacol 8: 42-49.
- Bessadok A, Garcia E, Jacquet H, Martin S, Garrigues A, et al. (2011) Recognition of sulfonylurea receptor (ABCC8/9) ligands by the multidrug resistance transporter P-glycoprotein (ABCB1): functional similarities based on common structural features between two multispecific ABC proteins. J Biol Chem 286: 3552-3569.
- Mishra MK, Ray D, Barik BB (2009) Microcapsules and transdermal patch: a comparative approach for improved delivery of antidiabetic drug. AAPS PharmSciTech 10: 928-934.
- Tosun C, Koltz MT, Kurland DB, Ijaz H, Gurakar M, et al. (2013) The Protective Effect of Glibenclamide in a Model of Hemorrhagic Encephalopathy of Prematurity. Brain Sci 3: 215-238.
- Rossignol S, Schwab M, Schwartz M, Fehlings MG (2007) Spinal cord injury: time to move? J Neurosci 27: 11782-11792.