The neuroprotective glycine receptor antagonist GV150526 does not produce neuronal vacuolization or cognitive deficits in rats.
The neuroprotective activity of the novel glycine receptor antagonist (E)-3[(phenylcarbamoil)ethenil]-4,6-dichloroindole-2-c arboxylic acid sodium salt) (GV150526) was recently reported in a model of focal ischemia in the rat. Here it was investigated whether GV150526 treatment results in any of the adverse side effects commonly detected after injection of NMDA (N-methyl-D-aspartate) receptor antagonists. First, it was found that neuronal vacuolization in the posterior cingulate/retrosplenial area of the cortex was not induced by GV150526 (200 mg/kg, i.v.), but was evident after injection of the NMDA receptor antagonist dizocilpine (MK801) (1 mg/kg, s.c.). In a second set of experiments, the effects of GV150526 were examined on perforant path-dentate gyrus long-term potentiation in rats. GV150526 (3 mg/kg, i.v.) injected 30 min or 150 min prior to tetanization did not block potentiation of the e.p.s.p. slope and population spike amplitude. In contrast, in animals treated with MK801 (1 mg/kg, i.p.) 150 min before tetanization there was a clear block of long-term potentiation of the e.p.s.p. slope and population spike amplitude. The effects of GV150526 were also examined in the Morris Water Maze. Rats injected with GV150526 (10 mg/kg or 60 mg/kg, p.o.) did not show any impairment in learning when compared to control. MK801 (0.08 mg/kg, i.p.), on the other hand, significantly affected the ability to locate the escape platform in the Water Maze. These findings show that GV150526 is devoid of adverse side effects even at doses well above those producing a neuroprotective effect. This, drug has therapeutic potential with a much greater margin of safety than NMDA channel blockers or competitive NMDA receptor antagonists.
Bordi
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F
Pharmacology Department, Glaxo-Wellcome Medicine Research Centre, Verona, Italy. fb23261@glaxowellcome.co.uk
Terron
A
A
Reggiani
A
A
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000473:pathology; D002540:Cerebral Cortex / Q000187:drug effects; D003072:Cognition Disorders / Q000139:chemically induced*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004347:Drug Interactions; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology; D019580:Perforant Pathway / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D018009:Receptors, Glycine / Q000037:antagonists & inhibitors; D013997:Time Factors; D014617:Vacuoles / Q000187:drug effects*
C105319:3-(2-((phenylamino)carbonyl)ethenyl)-4,6-dichloroindole-2-carboxylic acid; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D007211:Indoles; D018696:Neuroprotective Agents; D018009:Receptors, Glycine; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate