Effect of anaesthetics on the release of beta-endorphin-immunoreactivity in rat plasma.
Analgesia and anaesthesia produced by fentanyl, urethane and ether, but not pentobarbital, occurred concomitantly with an increase in the concentration of plasma beta-endorphin like immunoreactivity (BEIR), probably of pituitary origin. This increase was not associated with significant changes in pituitary or brainstem beta-endorphin content. Pretreatment with naloxone caused a reduction in plasma BEIR increase following Hypnorm, ether and urethane; and in the analgesia following Hypnorm and urethane. Pentobarbital, alone or in combination with naloxone, did not increase the concentration of plasma beta-endorphin. These results may indicate participation of endogenous opioids in the mechanism of action of urethane.
Ramirez-Gonzalez
M D
MD
Rudolf Magnus Institute for Pharmacology, University of Utrecht, The Netherlands.
Barna
I
I
Wiegant
V M
VM
de Jong
W
W
D000700:Analgesics / Q000494:pharmacology; D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D002090:Butyrophenones / Q000494:pharmacology; D004338:Drug Combinations; D004986:Ether / Q000494:pharmacology; D005283:Fentanyl / Q000494:pharmacology; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D010424:Pentobarbital / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D014520:Urethane / Q000494:pharmacology; D001615:beta-Endorphin / Q000097:blood* / Q000276:immunology
D000700:Analgesics; D000777:Anesthetics; D002090:Butyrophenones; D004338:Drug Combinations; D004986:Ether; D009270:Naloxone; D014520:Urethane; C001432:Hypnorm; D001615:beta-Endorphin; D010424:Pentobarbital; D005283:Fentanyl