Changes of salt intake and of (Na+K)-ATPase activity in brain after high dose treatment with deoxycorticosterone.
Mineralocorticoids (MC) have a dual effect on salt intake: in adrenalectomized rats, they reduce previously elevated salt intake; and in intact rats a high MC dose increases salt intake. We have studied the activity of (Na+K)-ATPase and [3H]ouabain binding in rats treated with deoxycorticosterone (DOC) in doses that elicited a salt appetite. Brains were removed from control and treated animals, and 20 different areas were punched out from brain slices cut every 300 microns. DOC treatment significantly reduced (Na+K)-ATPase activity in the lateral hypothalamic area, anterior amygdaloid and lateral amygdaloid nuclei, while increasing it in the periventricular gray matter; changes in other regions were not significant. Binding of [3H]ouabain was not modified by DOC treatment. In parallel experiments, we determined MC receptors in adrenalectomized rats. Binding of [3H]aldosterone was preferentially found in hippocampus, followed by lateral septum, anterior, posterior and lateral amygdaloid areas, with lower levels in other regions. However, there was no correlation between [3H]aldosterone binding and (Na+K)-ATPase activity in brain punches from either control or DOC-treated rats. Further experiments are needed to ascertain if (Na+K)-ATPase changes in discrete areas of the brain containing moderate levels of mineralocorticoid receptors, are related to the behavioral effects of DOC.
Grillo
C
C
Laboratorio de Bioquímica Neuroendócrina, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina.
Coirini
H
H
McEwen
B S
BS
De Nicola
A F
AF
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D003900:Desoxycorticosterone / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012982:Sodium, Dietary / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D012982:Sodium, Dietary; D003900:Desoxycorticosterone; D000254:Sodium-Potassium-Exchanging ATPase