Opioid mu and delta receptor antagonists reduce wet dog shaking elicited by perforant path stimulation.
Stimulation of the perforant path, a major input to the hippocampal formation, produced significant decreases in the hippocampal levels of methionine enkephalin, dynorphin A(1-8) and an increase in the hippocampal level of gamma-aminobutyric acid. In addition, it was also observed that both mu and delta opioid receptor antagonists reduce wet dog shakes elicited by perforant path stimulation. The antagonists did not affect the changes in hippocampal levels of methionine enkephalin, dynorphin A(1-8) or gamma-aminobutyric acid. The results demonstrate that endogenous opioids are involved in the wet dog shakes elicited by perforant path stimulation. Since electrographic seizure activity occurs in the hippocampus in conjunction with perforant path stimulation-induced wet dog shakes, these data provide further evidence that endogenous opioid peptides play an important role in regulation of limbic system epileptogenic phenomena.
Laboratory of Molecular and Integrative Neuroscience, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
C L
CL
Mitchell
M I
MI
Barnes
P M
PM
Hudson
J S
JS
Hong
D000818:Animals; D004399:Dynorphins / Q000378:metabolism; D004558:Electric Stimulation; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011957:Receptors, Opioid / Q000187:drug effects* / Q000502:physiology; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D013239:Stereotyped Behavior / Q000187:drug effects* / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D010446:Peptide Fragments; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D005680:gamma-Aminobutyric Acid; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D009271:Naltrexone; C024524:beta-funaltrexamine; D004399:Dynorphins; C026770:dynorphin (1-8); C040643:N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine