Ganglion-blockers, such as tetra-ethylammonium (TEA) and hexamethonium, enhance responsiveness to vasoactive agents, both pressor and depressor (1). In dogs, the renal arterial bed seems to contribute to the change in blood pressure response since, after giving TEA, adrenaline causes a larger increase and isopropylnoradrenaline (Isuprel@) a larger decrease in renal vascular resistance than in t...

Antihypertensive drug treatment is capable of aggravating angina pectoris in hypertensive patients with coronary artery disease. The complication appears to be due to different hemodynamic mechanisms. Angina pectoris caused by hydralazine may result not only from a reduction in aortic perfusion pressure but also from increases in cardiac output and pulse rate which the drug produces. Coronary i...

THE INCREASING clinical use of hexamethonium, a ganglion blocking agent, makes desirable a detailed knowledge of its acute hemodynamic effects in normotensive man. Recent work on dogs' indicates that the hexamethonium-induced fall in arterial pressure is accompanied by significant decrease in cardiac output with increase in the calculated total peripheral resistance. Accordingly, the authors co...

The fact that mecamylamine is a secondary amine with “nicotinic” blocking properties suggested it would act at the Golgi recurrent collateral-Renshaw-cell synapse in the spinal cord. Glass micropipettes were used to obtain extracellular Renshaw-cell discharges due to antidromic ventral root stimulation in cats anesthetized with pentobarbital. The effects of mecamylamine, hexamethonium, physosti...

The i.p. injection of nicotine produced several changes in regional catecholamine concentrations in rat brain. These changes were blocked by the centrally active nicotinic antagonist mecamylamine, but not by the quaternary nicotinic antagonist hexamethonium. An examination of the effects of various cholinergic agents on hypothalamic epinephrine concentrations revealed several interesting findin...