An in vitro study on the hippocampal electrophysiological properties of enkephalinase inhibitors in rats.
The effects of two enkephalinase inhibitors were studied on the CA1 and dentate hippocampal extracellular field potentials (FPs). The enkephalinase inhibitors thiorphan and SCH 32615, at a concentration of 1-500 microM, failed to significantly affect CA1 and dentate FPs. Thiorphan and SCH 32615, at a concentration of 150 microM, were able to potentiate the enkephalin-induced epileptiform bursting, inducing an increase in the bursting duration and in the number of spikes per burst due to 3.5 microM DAEAM or 0.20 microM DAGO. The results suggest: 1) the potentiation of an electrophysiological opiate receptor-mediated response by enkephalinase inhibitors; 2) the inability to show a direct effect on the basal CA1FP as a result of the inhibition of the endogenous enkephalinase.
Pharmacology Department, Istituto Superiore di Sanitá, Roma, Italy.
M L
ML
Proietti
S
S
Sagratella
C
C
Frank
M
M
Trampus
A
A
Scotti de Carolis
D000818:Animals; D004151:Dipeptides / Q000494:pharmacology; D004558:Electric Stimulation; D004594:Electrophysiology; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000494:pharmacology; D004745:Enkephalins / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D015260:Neprilysin / Q000037:antagonists & inhibitors*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D015244:Thiorphan / Q000494:pharmacology
D004151:Dipeptides; D004745:Enkephalins; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004744:Enkephalin, Methionine; C022118:enkephalinamide-Met, Ala(2)-; C062344:SCH 32615; D015244:Thiorphan; D015260:Neprilysin