Chronic serotonergic blockade with ketanserin in the spontaneously hypertensive rat

Spontaneously hypertensive rats were fed ketanserin-enriched (17 mg/100 g) or control chow for 6 weeks. After 6 weeks the blood pressure was reduced (16%). Pressor responses to phenylephrine were not different from control responses, which indicates that at this time the antihypertensive effect was not directly related to an alpha-adrenoceptor blockade. Cardiovascular responses to stress (jet air), baroreceptor sensitivity (bradycardia to phenylephrine), and central catecholamine turnover were unchanged, which supported the view that central mechanisms probably do not contribute to the antihypertensive effects of ketanserin.