5-Receptor antagonists pharmacological activity

Ko FN, Yu SM, Su MJ, Wu YC, Teng CM. Pharmacological activity of (-)-discreta-mine, a novel vascular alpha-adrenoceptor and 5-hydroxytryptamine receptor antagonist, isolated from Fissistigma glaucescens. BrJ Pharmacol. 1993 110 882-888. 

Angiotensin II causes vasoconstriction by direct stimulation of ATj receptors on the vascular smooth muscle. It also enhances release of the neurotransmitter norepinephrine from the sympathetic nerve fibers present in the blood vessels. The vasopressor effects of Ag II may be inhibited pharmacologically in order to decrease TPR and treat hypertension. An important class of orally active drugs is the ACE inhibitors, including captopril and enalopril, which prevent formation of Ag II. More recently, angiotensin receptor antagonists have been developed that act at the vascular smooth muscle. These drugs, which include losartin and valsartan, are also orally active. 

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