Cyanamide-induced activation of the hypothalamo-pituitary-adrenal axis

The present study investigated the effects of acute administration of cyanamide (a potent inhibitor of aldehyde dehydrogenase used to treat alcoholics), on the hypothalamo-pituitary adrenal (HPA)-axis. Cyanamide resulted in a significant increase in arginine vasopressin mRNA and corticotrophin releasing factor (CRF) mRNA in the parvocellular cells of the paraventricular nucleus and pro-opiomelanocortin (POMC) mRNA in the anterior pituitary. Plasma corticosterone concentrations were elevated by a range of doses of cyanamide which were maintained in the high dose group at 4 h following administration. These results suggest that cyanamide is able to activate the HPA axis at all levels of the axis. Arginine vasopressin mRNA, in the parvocellular cells of the paraventricular nucleus is an important component of the stress response. Silver grain counting of emulsion dipped slides is commonly used for its evaluation following in-situ hybridization. This method is however, not entirely satisfactory and very time-consuming. We compared this method with a film autoradiographic method, and show that the film autoradiographic method is valid for the determination of arginine vasopressin mRNA in the parvocellular cells of the paraventricular nucleus.