title: A Highly Selective Inhibitor of Glycine Transporter-1 Elevates the Threshold for Maximal Electroshock-Induced Tonic Seizure in Mice.
abstract: Many anti-epileptic drugs (AEDs) that mainly target ion channels or post-synaptic receptors are in clinical use, but a proportion of patients are resistant to these traditional AEDs and experience repeated severe break-out seizures. Given its involvement in the etiology of epilepsy, the neurotransmitter glycine may serve as a novel target for epilepsy treatment. Increasing evidence suggests that inhibitors of glycine transporter 1 (GlyT1) exhibit anti-seizure properties in mouse models and show potential as anti-convulsions drugs. In the present study, we investigated the effect of a highly selective GlyT1 inhibitor (named M22) on glycine transport kinetics using a radioactive substrate uptake assay and investigated the anti-seizure effects of M22 on the maximal electroshock seizure threshold (MEST) test and the timed intravenous (i.v.) pentylenetetrazole (PTZ) intravenous test. Our results demonstrate that M22 was capable of elevating the seizure threshold in the MEST test but did not alter the seizure threshold in the PTZ i.v. test. Strychnine, an inhibitor of glycine receptor activity, reversed the threshold elevation at a subconvulsive dosage (0.1 mg/kg subcutaneously) in the MEST test and did not affect M22 plasma levels in mice, suggesting that the anti-seizure effect in this model may be mediated by increased glycine receptor activity. Moreover, M22 administration did not influence motor function and coordination in mice. In combination with the previously reported excellent pharmacokinetic features of M22, our present results suggested that M22 has the potential to serve as a new anti-convulsive drug or as a lead compound for the development of AEDs.
authors.affiliation: Institute of Neurology, Affiliated Hospital of Guangdong Medical University.
authors.forename: Jianghao
authors.initials: J
authors.lastname: Zhao
authors.forename: Hua
authors.initials: H
authors.lastname: Tao
authors.forename: Wenchuan
authors.initials: W
authors.lastname: Xian
authors.forename: Yujie
authors.initials: Y
authors.lastname: Cai
authors.forename: Wanwen
authors.initials: W
authors.lastname: Cheng
authors.forename: Mingkang
authors.initials: M
authors.lastname: Yin
authors.forename: Guocong
authors.initials: G
authors.lastname: Liang
authors.forename: Keshen
authors.initials: K
authors.lastname: Li
authors.forename: Lili
authors.initials: L
authors.lastname: Cui
authors.forename: Bin
authors.initials: B
authors.lastname: Zhao
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004597:Electroshock / Q000009:adverse effects*; D050487:Glycine Plasma Membrane Transport Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D007275:Injections, Intravenous; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D015394:Molecular Structure; D010433:Pentylenetetrazole / Q000008:administration & dosage / Q000633:toxicity; D010880:Piperidines / Q000494:pharmacology*; D012640:Seizures / Q000209:etiology / Q000517:prevention & control*; D013331:Strychnine / Q000633:toxicity
chemical_list: D000927:Anticonvulsants; D001549:Benzamides; D050487:Glycine Plasma Membrane Transport Proteins; D010880:Piperidines; C493270:Slc6a5 protein, mouse; C493267:Slc6a9 protein, mouse; C000604918:VU0410120; D013331:Strychnine; D010433:Pentylenetetrazole