Effect of capsaicin neonatal treatment on the salt intake of the adult rat.

The present study investigated the involvement of capsaicin-sensitive sensory neurons on salt intake control in the rat, following capsaicin neonatal treatment. Capsaicin did not affect salt appetite induced by intramuscular injection of deoxycorticosterone enantate, or by intracranial injection of renin. Moreover, it did not alter salt preference of rats given access to a variety of NaCl concentrations, or the need-free salt intake of multidepleted male rats. On the other hand, in response to furosemide-induced sodium depletion, the salt intake of capsaicin-treated rats was lower than that of controls. However, furosemide-induced Na+ excretion of capsaicin-treated rats proved to be lower than that of controls, thus suggesting that difference in salt intake might be secondary to lower sensitivity of capsaicin-treated rats to the natriuretic action of furosemide. Salt intake is known to be influenced by sensory information from the oral cavity, from the liver and from the intravascular compartment. The absence of effect of capsaicin neonatal treatment suggests that sensory fibers relevant to salt intake control may not be capsaicin sensitive. On the other hand, our findings indicate that capsaicin treatment alter