Peptidergic mechanisms of hyperthermia-evoked convulsions in rats in early postnatal ontogenesis.

This report addresses the verification of the hypothesis that arginine-vasopressin affects the formation of hyperthermia-evoked convulsions in early ontogenesis in rats on days 3, 5, 7, and 9 of postnatal life. The modification of experimental febrile convulsions by PACAP (pituitary adenylate cyclase-activating peptide) was investigated; PACAP is a physiological regulator of the neurosecretion of arginine-vasopressin. Arginine-vasopressin (10 microg/rat) and PACAP (0.01 microg/rat) decreased the latency of generalized tonic-clonic convulsions and the time of truncal generalization of convulsive activity on days 3 and 5 of rat development. Animals given arginine-vasopressin (0.1-10 microg/rat) sowed significant increases in the duration of generalized convulsions to the level of status epilepticus on day 9 of life. Conversely, administration of higher doses of PACAP (0.1 microg/rat) increased the threshold of tonic-clonic convulsions on days 3 and 5 and decreased it on days 7 and 9 of postnatal development. The indirect involvement of PACAP in the mechanisms of experimental febrile convulsions is suggested to act via changes in arginine-vasopressin neurosecretion.