Salt appetite of adrenalectomized rats after a lesion of the SFO

Circumventricular organs such as the subfornical organ (SFO) may mediate the effects of circulating angiotensin (ANG) II on salt appetite under conditions of sodium depletion in the rat. We studied the effects of an electrolytic lesion of SFO on salt appetite after adrenalectomy (ADX) in Long-Evans rats. The SFO lesion had no effect on saline intake, but it did abolish water intake after acute peripheral treatments with 2 mg/kg of captopril or a 10 mg/kg of furosemide. These findings contrast with other recent data from this laboratory demonstrating large reductions in salt appetite in adrenal-intact rats with lesions of either SFO or the organum vasculosum laminae terminalis during acute iv infusions of ANG II. Thus, the SFO may contribute to the salt appetite response to circulating ANG II, but it is not essential for the response to adrenalectomy.