Influence of body temperature on the epileptogenic effect of enkephalin microinjections into the hippocampus.
The influence of different body temperatures on the epileptiform discharges induced in hippocampus by local microinjections of leu-enkephalin was studied in rats. In the absence of enkephalin, changes in body temperature by either cooling or heating induced epileptiform discharges that disappeared after temperature stabilization. The epileptiform episode induced by enkephalin microinjections was of longer duration at temperature below normal (29-30 degrees C). At body temperature above normal (39-40 degrees C) the epileptiform discharge was less intense and of shorter duration. In vitro testing led to parallel results: the destruction of enkephalin by the brain tissue was faster at higher temperatures. It is proposed that in conditions of hyperthermia enkephalin has a weaker activity due to acceleration of the activity of peptidases involved in its breakdown.
D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D004723:Endorphins / Q000494:pharmacology*; D004743:Enkephalin, Leucine; D004745:Enkephalins / Q000378:metabolism / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000139:chemically induced*
D004723:Endorphins; D004745:Enkephalins; D004743:Enkephalin, Leucine