Central histaminoceptor-adrenoceptor interrelations in the release of adrenocorticotrophic hormone

Intracerebroventricular administration of adrenaline, noradrenaline phenylephrine, clonidine and histamine produced a significant rise in plasma cortisol concentration whereas isoprenaline had no effect. alpha-Adrenoceptor blockers (yohimbine or piperoxon) per se did not alter the plasma cortisol level. Central pretreatment with yohimbine or piperoxin, blocked the rise in plasma cortisol level induced by icv noradrenaline, phenylephrine and clonidine. In another set of experiments, both H1 and H2 receptor antagonists (mepyramine, and metiamide) per se had not significant effect on plasma cortisol concentration. Central histamine induced rise in plasma cortisol concentration was significantly blocked by icv pretreatment with both H1 and H2 receptor blockers. Furthermore, yohimbine also significantly prevented the rise of plasma cortisol level induced by icv histamine.