Drug administration into the third ventricle of the brain of anesthetized and conscious cats

A method is described for the administration of drugs into the third ventricle of the brain of conscious and anesthetized cats. Noradrenaline administered by this route produced cardiovascular stimulant effects as against depressor effects when administered into a lateral cerebral ventricle. The pressor responses evoked by third ventricular administration of noradrenaline were antagonized by spinal section in anesthetized cats and by hexamethonium in conscious animals. Conscious cats were more sensitive to the pressor effects of third ventricular noradrenaline than chloralose-anesthetized animals.