Involvement of nitric oxide in central histaminergic stimulation of the hypothalamic-pituitary-adrenal axis.
Brain histamine participates in central regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Endogenous nitric oxide (NO) modulates signal transduction of some neurotransmitters involved in activation of the HPA axis. In the present study we investigated whether endogenous NO and histaminergic systems in the rat brain interact in their regulation of ACTH and corticosterone secretion. Histamine (50 microg), histamine-trifluoromethyl-toluidide derivative (HTMT, 75 microg) a selective and potent H1-receptor agonist, and amthamine (75 microg) a H2-receptor agonist given intracerebroventricularly (i.c.v.) considerably increased ACTH and corticosterone secretion 1 h after administration. A potent and competitive inhibitor of rat brain neuronal NO synthase, (NOS), 7-nitroindazole (7-NI), given i.p. 15 min before histamine moderately increased the histamine-induced ACTH secretion and did not substantially alter the histamine-induced corticosterone secretion. Pretreatment with 7-NI totally abolished the HTMT-induced increase in ACTH and corticosterone secretion. The amthamine-evoked rise in ACTH secretion was moderately diminished and the amthamine-induced corticosterone secretion was not substantially altered by preatreatment with 7-NI. These results suggest that the histamine H -receptor transmited central stimulation of the HPA axis is considerably mediated by endogenous NO, whereas stimulation by histamine and via H2-receptor does not significantly depend on endogenous NO mediation.
Bugajski
A J
AJ
Department of Pathophysiology, Jagiellonian University Medical College, Cracow, Poland.
Koprowska
B
B
Thor
P
P
Głod
R
R
Bugajski
J
J
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000502:physiology*; D003345:Corticosterone / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006632:Histamine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000502:physiology*; D007191:Indazoles / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D004791:Enzyme Inhibitors; D007191:Indazoles; C087869:histamine trifluoromethyl-toluidide; D009569:Nitric Oxide; D006632:Histamine; D000324:Adrenocorticotropic Hormone; C080122:7-nitroindazole; D003345:Corticosterone