Different effects of chronic K+ depletion on forebrain and peripheral angiotensin II receptors in young rats

K+ depletion stimulates the circulating renin-angiotensin system and affects the regulation of peripheral angiotensin II receptors. The effects of K+ depletion on the regulation of central angiotensin II receptors are unknown. We studied the effects of selective K+ depletion (< 0.05% in diet for 16 days) on angiotensin II receptor number in kidneys, adrenal glands, and selected brain areas of young rats. K+ depletion caused a significant increase in plasma renin activity and significantly decreased angiotensin II receptor number in the kidney glomeruli and medulla, and in the adrenal zona glomerulosa and adrenal medulla. In the brain, the angiotensin II receptor number was unchanged in the subfornical organ and the hypothalamic paraventricular nucleus after 16 days of K+ depletion. An additional NaCl supplementation (0.02% in the drinking water) to K+-depleted rats produced a decrease in plasma renin activity but failed to affect subfornical organ or paraventricular angiotensin II receptor number. Our results suggest that in young animals, K+ depletion has a significant impact on the peripheral renin-angiotensin system without affecting the density of forebrain angiotensin II receptors.