THE EFFECT OF AN ADRENERGIC BETA-RECEPTOR ANTAGONIST ON THE CARDIOVASCULAR SYSTEM OF THE DOG

¹ Sections of Surgical Research and Physiology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota

Nethalide (1-[2'-naphthyl]-2-isopropylaminoethanol hydrochloride) was studied in normal and in atropinized dogs under pentobarbital anesthesia and in dogs with chronic cardiac denervation. When given intravenously in a dose of 6 to 7 mg/kg, it increased cardiac output and stroke volume. The heart rate slowed in normal and in atropinized dogs, was unchanged in dogs with cardiac denervation when anesthetized, and quickened when they were conscious. It can block the -receptors in peripheral vessels and can abolish the effect of stimulation of the cardiac sympathetic nerves. It can block the chronotropic effects of norepinephnine and epinephrine.