Central lead administration induces natriuretic and kaliuretic effects in rats

Abstract

FREGONEZE, J. B., C. P. LUZ, C. SARMENTO, V. GONZALEZ, P. OLIVEIRA, P. SANTANA, JR., C. A. MARINHO, L. CASTRO, T. NASCIMENTO, S. DE PAULA, A. K. S. LIMA, I. R. DE OLIVEIRA AND E. DE CASTRO-E-SILVA. Central lead administration induces natriuretic and kaliuretic effects in rats. PHYSIOL BEHAV 65(2) 321–326, 1998.—The aim of the present experiments was to discern whether central acute lead injections affect brain control of renal function. Adult Wistar male rats received third-ventricle injections of lead acetate in three different doses (0.03, 0.3, and 3.0 nmol/rat). Lead acetate induced a significant increase in renal excretion of sodium and potassium. Pretreatment with losartan, a selective angiotensin II AT1 receptor antagonist (10.8 nmol/rat into the third ventricle 10 min before central lead injection), inhibits lead-induced natriuretic and kaliuretic effects. In addition, pretreatment with gadolinium, a calcium-channel blocker (0.3 nmol/rat into the third ventricle 20 min before central lead administration), reversed the increase in renal excretion of sodium and potassium provoked by central lead administration. Taken together, the data presented here suggest that lead injected into the third ventricle increases renal excretion of sodium and potassium by a mechanism that depends on the functional integrity of central angiotensin II AT1 receptors and calcium channels.