Endothelium-Dependent vs. Independent Vasodilators

A number of vasodilators, such as acetylcholine, bradykinin, adenine nucleosides, thrombin, histamine, and serotonin, require an intact vascular endothelium to exert their effects. For example, stimulation of endothelial cholinergic receptors causes the release of endothelium-derived relaxing 

FIGURE 35.9 Neurohumoral activation during myocardial failure. 

The vasodilating properties of captopril or hydralazine (antihypertensive agents) are mediated by the formation of EDRF or prostaglandin, or both. On the other hand, the vasodilating properties of nitroprusside (an antihypertensive agent) result directly from the formation of cyclic GMP. 

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