Pentylenetetrazol-induced seizures increase [H-3]L-2-amino-4-phosphonobutyrate binding in discrete regions of the rat brain

Convulsions were induced in rats by a single injection of pentylenetetrazol (PTZ) and [H-3] L-2-amino-4-phosphonobutyrate ([H-3]L-AP4) in vitro recept or autoradiography was used to evaluate the effects on the expression of gr oup III metabotropic glutamate receptors. Significant increases by 60-80% i n [H-3]L-AP4 binding was observed in the frontal parts of cortex (sensory, motor and cingulate cortex) and by 28% in the molecular layer of the cerebe llar cortex 24 h after PTZ-induced seizures. Since group III metabotropic g lutamate receptors has an inhibitory effect on glutamatergic transmission, the observed increases in binding may indicate that these receptors serve a s a mechanism for preventing further seizure activity. (C) 1999 Elsevier Sc ience Ireland Ltd. All rights reserved.