Final answer:
Hydralazine treats hypertension by directly causing vasodilation of arterioles, reducing systemic vascular resistance and lowering blood pressure. It does not have a selective action on cerebral, coronary, or renal vessels, nor does it act as an alpha agonist or affect cAMP levels.
Step-by-step explanation:
Mechanism of Action of Hydralazine
The drug in question is hydralazine, which is primarily used to treat hypertension. Its mechanism of action involves direct vasodilation of arterioles, leading to a reduction in systemic vascular resistance and ultimately decreasing blood pressure. This vasodilation effect of hydralazine increases the glomerular filtration rate and decreases sodium reabsorption in the kidneys, which contributes to its antihypertensive effects. Moreover, hydralazine is not known to have a selective action on cerebral, coronary, or renal vessels specifically, nor does it act as an alpha agonist or increase cAMP levels. Hydralazine's action is unrelated to central nervous system activity, and the descriptive elements provided appear to confuse the effects of catecholamines and other vasoactive agents with those of hydralazine.
To answer the student's question, the correct option would be 'C. None of the above' as the other choices do not accurately describe the mechanism of action of hydralazine.