Roles of metabotropic glutamate receptor subtypes in modulation of pentylenetetrazole-induced seizure activity in mice.

Abstract

The anticonvulsant or proconvulsant properties of ligands at metabotropic glutamate receptors (mGluRs) were examined in a chemoconvulsant model using pentylenetetrazole (PTZ). Mice received mGluR ligands by intracerebroventricular (i.c.v.) infusion prior to a subcutaneous injection of PTZ and the latency to onset of tonic convulsions was recorded. The group I mGluR antagonist 1-aminoindan-1,5-dicarboxylic acid (AIDA) dose-dependently antagonised PTZ-induced seizures with a mean ED50 value of 465 nmol. In contrast, the selective group I mGluR agonist, (S)-3,5-dihydroxyphenylglycine [(S)-DHPG], was proconvulsive and decreased the PTZ-induced seizure latency (ED50=60 nmol i.c.v.). A selective agonist of group II mGluRs, (1S,3S)-1-aminocyclopentane dicarboxylic acid [(1S,3S)-ACPD], was proconvulsive but did not affect PTZ-induced seizure latency. Moreover, the proconvulsant effect of (IS,3S)-ACPD was not blocked by the mGluR2 antagonist, alpha-methylserine-O-phosphate monophenyl ester but was blocked by AIDA suggesting the involvement of group I mGluRs. (2S,1'S,2'S,3'R)-2-(2'-carboxy-3'-phenylcyclopropyl)glycine (PCCG-IV), which is a potent mGluR2 antagonist and a group III mGluR agonist at higher doses, increased the PTZ-induced seizure latency (ED50=51 nmol) and this effect was fully reversed by the group III mGluR antagonist, (S)-2-amino-2-methyl-4-phosphonobutanoic acid (MAP4). Similarly, the group III mGluR agonist 1-amino-3-(phosphonomethylene)cyclobutanecarboxylate (cyclobutylene-AP5) increased the PTZ-induced seizure latency (ED50=12 nmol) in a MAP4-sensitive manner. Collectively, these data suggest that mGluR ligands modulate PTZ-induced seizure activity in mice by either antagonizing group I mGluRs or activating group III mGluRs.

• Authors: C Thomsen, N O Dalby
• Journal: Neuropharmacology (Neuropharmacology) Vol. 37 Issue 12 Pg. 1465-73 (Dec 1998) ISSN: 0028-3908 [Print] England
• PMID: 9886669 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 1-aminoindan-1,5-dicarboxylic acid
• Excitatory Amino Acid Antagonists
• Indans
• Resorcinols
• Cycloleucine
• 1-amino-1,3-dicarboxycyclopentane
• 3,5-dihydroxyphenylglycine
• Glycine
• Pentylenetetrazole

Topics

• Animals
• Cerebral Ventricles (drug effects, physiology, physiopathology)
• Cycloleucine (administration & dosage, analogs & derivatives, pharmacology)
• Excitatory Amino Acid Antagonists (administration & dosage, pharmacology)
• Glycine (administration & dosage, analogs & derivatives, pharmacology)
• Indans (administration & dosage, pharmacology)
• Infusions, Parenteral
• Male
• Mice
• Mice, Inbred Strains
• Pentylenetetrazole (toxicity)
• Reaction Time
• Resorcinols (administration & dosage, pharmacology)
• Seizures (chemically induced, physiopathology)