The effect of kainic acid (KA), a potent neurotoxic agent, on the renal function of rats was investigated. Intrahippocampal and intraperitoneal KA injections (2.5 micrograms and 8 mg/kg, respectively) led to a decrease in glomerular filtration rate and U/P inulin ratio with a concomitant increase in the amount of excreted Na+. However, acid excretion was maintained. These findings support the idea of a straight connection between neurohormonal secretion and renal function and may provide an interesting model to study renal hemodynamic changes induced by neurological disturbances.