SUSTAINED HYPERTENSION IN DOGS FOLLOWING CHRONIC ADMINISTRATION OF GANGLIONIC BLOCKING AGENTS

¹ Instituto Miles de Terapeutica Experimental, Calzada Xochimilco 77, Mexico, D. F., Mexico

Sustained elevated systolic and diastolic blood pressures were observed in dogs following the chronic daily oral administration of mecamylamine and chiorisondamine. The hypertension, once developed, was maintained despite substitution of the ganglionic blocking agent by a placebo. It could be lowered by the administration of hydrochlorothiazide, reserpine and phenoxybenzamine. Development of hypertension did not follow the chronic administration of hydrochlorothiazide or phenoxybenzamine. It is suggested that the effect may develop through a prolonged blockade of the sympathetic pathways believed to regulate mechanoreceptor sensitivity, resulting in "false" information being delivered to the central vasomotor areas and in a consequent readjustment in the mechanism regulating blood pressure.