Effects of salt and DOCA on hypothalamic and baroreflex control of blood pressure

Cardiovascular and sympathetic nerve responses to electrical stimulation of either the aortic depressor nerve (ADN) or the posterior hypothalamus were recorded from rats treated with salt, DOCA, or DOCA/salt and compared with those from untreated controls. By the 7th day, tail-cuff systolic pressures were significantly elevated in rats treated with salt or DOCA/salt. And by the 21st day, all treated rats (i.e. with salt, DOCA, or DOCA/salt) had elevated pressures together with attenuated ADN responses and augmented hypothalamic responses. After 5 days, DOCA/salt treated rats already had attenuated responses to ADN stimulation and augmented responses to hypothalamic stimulation even though their systolic pressures were still unaltered. These findings suggest that combined treatment with salt and DOCA altered central blood pressure regulation even before hypertension developed.