EFFECT OF LESIONS IN SEPTAL AREA AND OLFACTORY BULBS ON SODIUM CHLORIDE INTAKE

Spontaneous sodium chloride intake in rats with lesions in the septal area or olfactory bulbs and normal rats were studied. Normal rats prefer 1% NaCl solutions when allowed to choose concentrations from 0.5%-3% NaCl and tap water. Animals with septal area or olfactory bulb lesions increase the 1% NaCl intake as compared with prelesion values. This effect was still evident 4 months later. The high NaCl intake is not related to an altered renal sodium excretion. The sodium depletion leads to a significant increase of Na intake in all animals, but the highest values are observed in lesioned animals. In Na-depleted rats, sodium overload reduced the sodium ingestion to normal values. It is postulated that, in the regulation of Na intake, a dual mechanism exists, inhibitory and stimulatory, and that the limbic system may be related to the inhibitory influences. © 1969.