Alpha2-Adrenoceptors in Brain and Kidney during Development of Hypertension in Dahl-Iwai Salt-Sensitive Rats

Background: Both renal and extrarenal factors have been considered to contribute to the development of hypertension in Dahl salt-sensitive rats, but contents of both factors have not been established precisely.Aim: To clarify the role of those factors in the sympathetic nervous system, we examined the regulation of alpha2-adrenoceptors in the lower brainstem and the renal tubular basolateral membranes simultaneously during the development of salt-induced hypertension in Dahl-lwai salt-sensitive rats.Methods: Dahl-lwai salt-sensitive or resistant rats were fed a high (8.0 % NaCI)- or low (0.3 %)- salt diet from 4 to 6 or 10 weeks of age. At 4, 6 and 10 weeks of age, the plasma membranes of the lower brainstem and the renal tubular basolateral membranes were obtained simultaneously and alpha2-adrenoceptors were quantified by a radioligand binding assay using 3H-rauwolscine.Results: In the salt-sensitive rats, systolic blood pressure was significantly higher in those fed a high-salt diet than in those fed a ...