Failure to Produce Blood Pressure Changes Following Pharmacological or Surgical Depletion of Brain Serotonin in the Spontaneously Hypertensive Rat

Abstract

Spontaneously hypertensive (SH) and normotensive (Wistar-Kyoto, WKY) rats were examined for blood pressure changes following depletion of CNS serotonin (5-HT) by 3 separate techniques: (1) p-chorophenylalanine, (2) 5,7-dihydroxydrytamine, and (3) a lesion of the dorsal and median raphe nuclei. All of these procedures failed to alter blood pressure in either hypertensive or normotensive rats, despite marked reductions (75–85%) in fore-brain 5-HT. Moreover, treatment of 10 day-old hypertensive rat pups with intracisterual injections of 5,7-DHT (10 μg) failed to alter the development of hypertension despite a 75–80% decrease in spinal cord 5-HT. These findings, which show that 5-HT depletion does not alter blood pressure in the SH or the WKY rat, do not lend support to the idea that 5-HT is involved in the regulation of blood pressure or in the development and maintenance of hypertension in the SH rat.