The significance of brain histamine and its receptors in opioid stimulation of the pituitary-adrenocortical activity.
The involvement of brain histamine, contained in mast cells and neurons, and central histamine receptors in stimulation of the pituitary-adrenal axis by opioids was investigated indirectly through corticosterone secretion in conscious rats. The opioid agonists leu-enkephalinamide (DADL), morphine and b-endorphin (b-End) the s- m- and putative e-opioid receptor agonists, given intracerebroventricularly (ici) induced a significant, dose-dependent increase in serum corticosterone levels. The corticosterone response to b-End and morphine was significantly impaired by pretreatment with mepyramine and cimetidine, whereas the response to DADL was insensitive to histamine antagonists. Twenty four hours after administration of compound 48/80 the corticosterone responses to the opioids were greatly diminished. Pretreatment with a-fluoromethylhistidine (a-FMH), a histamine synthesis inhibitor, almost abolished the corticosterone response to DADL, b-End and morphine. These results indicate that central neuronal histamine and histamine receptors are significantly involved in the opioid-induced stimulation of the pituitary-adrenal axis in rats.
Bugajski
J
J
Institute of Pharmacology, Polish Academy of Sciences, Kraków.
Turon
M
M
Tyton
J
J
D000302:Adrenal Cortex / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000502:physiology*; D002927:Cimetidine / Q000494:pharmacology; D003345:Corticosterone / Q000097:blood; D004723:Endorphins / Q000494:pharmacology*; D016308:Enkephalin, Leucine-2-Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D006632:Histamine / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D006640:Histidine Decarboxylase / Q000037:antagonists & inhibitors; D008297:Male; D009020:Morphine / Q000494:pharmacology; D010902:Pituitary Gland / Q000187:drug effects / Q000502:physiology*; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011968:Receptors, Histamine / Q000502:physiology*; D001615:beta-Endorphin / Q000494:pharmacology; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D004723:Endorphins; D011968:Receptors, Histamine; D003189:p-Methoxy-N-methylphenethylamine; D001615:beta-Endorphin; D016308:Enkephalin, Leucine-2-Alanine; C030279:enkephalinamide-Leu, Ala(2)-; C054284:alpha-fluoromethylhistamine; D009020:Morphine; D002927:Cimetidine; D006632:Histamine; D006640:Histidine Decarboxylase; D011738:Pyrilamine; D003345:Corticosterone