Ganglion-blocking agent

That is, the pressure is adjusted automatically in response to signals from various baroreceptors. Control of abnormally high pressure can, at least in theory, be achieved by interfering with the chain of transmission of the neural signals that lead to elevation of pressure. Initial success in control of hypertension was met with the ganglionic blocking agents which in effect in-... 

Ganglionic blocking agent. A drug that blocks neurotransmission at the nicotinic receptors of the sympathetic ganglia, thus blocking vascular reflexes. 

A number of years ago, pentamethylpiperidine 55 was found to be a rather potent, though not very specific, ganglionic blocking agent. This finding was of particular interest, as it was at that time believed that a quaternary ammonium function was a... 

All of the responses summarized in Table 14.2 can be produced by administration of ganglionic blocking agents. Many of these responses are undesirable effects that limit the therapeutic usefulness of these agents. Mild untoward responses include mydriasis, difficulty in vision accommodation, dry mouth, urinary hesitancy, constipation, diarrhea, abdominal discomfort, anorexia, and syncope. More serious but less frequent disturbances include marked hypotension, constipation, paralytic ileus, urinary retention, and anginal pain. 

Ganglionic blocking agents are rarely used because of the numerous side effects they may produce. One such side effect is... 

C. Trimethaphan is a ganglionic blocking agent that will lower blood pressure very rapidly. Hydralazine is a vasodilator hydrochlorothiazide and spironolactone are diuretics and methyldopa is a sympatholytic acting in the central nervous system. All of these drugs are used clinically as antihypertensive agents. None work as rapidly as trimethaphan. Clinically, however, either nitroprusside or clonidine is used much more commonly than trimethaphan in this situation. 

A more complete description of trimethaphan and other ganglionic blocking agents can be found in Chapter 14. 

The answer is d. (Hardman, pp 192-193.) Nicotine is a depolarizing ganglionic blocking agent that initially stimulates and then blocks nicotinic muscular (NM) (skeletal muscle) and nicotinic neural (NN) (parasympathetic ganglia) cholinergic receptors. Blockade of the sympathetic division of the autonomic nervous system (ANS) results in arteriolar vasodilation, bradycardia, and hypotension. Blockade at the neuromuscu-... 

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