Roles of brain prostaglandin E2 and thromboxane A2 in the activation of the central sympatho-adrenomedullary outflow in rats.
We examined the effects of centrally administered active metabolites of the arachidonic acid cascade on activation of the central sympatho-adrenomedullary outflow using urethane-anaesthetized rats. Intracerebroventricularly (i.c.v.) administered prostaglandin E(2) (0.3 nmol/animal) significantly elevated plasma levels of noradrenaline while levels of adrenaline were not affected. Prostaglandin D(2), prostaglandin F(2 alpha) and prostaglandin I(2) at the same dose (0.3 nmol/animal, i.c.v.) had no effect on plasma levels of either catecholamine. Thromboxane A(2) mimetic, 7-[3-[3-hydroxy-4-(4-iodophenoxy)-1-butenyl]-7-oxabicyclo [2.2.1]hept-2-yl], [1S-[1 alpha,2 alpha(Z),3beta(1E,3S),4 alpha]]-5-heptenoic acid (I-BOP) (5 and 10 pmol/animal) microinjected into the paraventricular nucleus of the hypothalamus significantly elevated plasma levels of adrenaline, but had little effect on plasma levels of noradrenaline. The I-BOP-induced (10 pmol/animal) elevation of plasma adrenaline levels was abolished by (+)-(1R,2R,3S,4S)-(5Z)-7-(3-[4-3H]-phenylsulphonyl-aminobicyclo[2.2.1]hept-2-yl)hept-5-enoic acid sodium salt [(+)-S-145] (a blocker of thromboxane A(2) receptors) [625 nmol (250 micro g)/animal, i.c.v.]. These results suggest that brain prostaglandin E(2) and thromboxane A(2) are respectively involved in the activation of the central sympathetic and adrenomedullary outflow in rats.
D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D015232:Dinoprostone / Q000494:pharmacology* / Q000502:physiology; D004837:Epinephrine / Q000097:blood*; D007276:Injections, Intraventricular; D008297:Male; D009638:Norepinephrine / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000378:metabolism; D013928:Thromboxane A2 / Q000494:pharmacology* / Q000502:physiology
D013928:Thromboxane A2; D015232:Dinoprostone; D009638:Norepinephrine; D004837:Epinephrine