Chronic DOCA‐salt treatment alters hypothalamic, but not cortical or brainstem, Na+/K+/Ca2+ content

Abstract

The present study was conducted to establish whether chronic salt loading alone, or in combination with the mineralocorticoid deoxycorticosterone acetate (DOCA), alters the content of sodium (Na+), potassium (K+) and calcium (Ca2+) in the brain. Male Sprague Dawley rats were implanted with a silicone pellet containing 0 (n=6) or 100 (n=6) mg DOCA and given 0.9% saline to drink ad libitum. The control group received 0mg DOCA and water ad libitum (n=6). After 21 days of treatment rats were anesthetized and brains were excised. The brainstem was removed and the remainder of the brain was bisected midsagitally. The right half of the brain was weighed intact and the left half was dissected into hypothalamus and cortex. Samples were analyzed for Na+/K+/Ca2+ content (ppm/gram) by inductively coupled argon plasma optical emission spectrometry. Compared to the control group, saline loading alone had no effect on Na+/K+/Ca2+ in any brain region. However, DOCA‐salt treatment increased Na+ (p < 0.05), and tended to decrease K+ content (p >; 0.05), in the hypothalamus but had no effect in the cortex or brainstem. DOCA‐salt treatment also increased hypothalamic (p < 0.05), but not cortical or brainstem, Ca2+ content. We conclude that regulation of hypothalamic Na+/K+/Ca2+ content is unique compared to the cortex and brainstem. HL64176–05