BOMBESIN AFFECTS THE CENTRAL-NERVOUS-SYSTEM TO PRODUCE SODIUM-INTAKE INHIBITION IN RATS

Bombesin (BN) elicits in the rat important behavioural modifications, including inhibition of food and of water intake. Recently, it has bee n observed that the peptide also inhibits the intake of sodium chlorid e. To stare whether BN possesses a selective antinatriorexic effect or it elicits only an aspecific depression of ingestive behaviour, we st udied the effects of this peptide on the intake of sodium, water or su crose of Wistar rats after injections into the fourth brain ventricle or into selected brain areas involved in the control of sodium intake, containing BN-like peptides and/or their precursors or specific recep tors. We observed that: a) BN (100-200 ng/rat) injected into the fourt h brain ventricle inhibits not only the intake of 2% NaCl of sodium de pleted rats but also that of water and of 5% sucrose; b) BN (5-50 ng/r at) administered into the nucleus of the solitary tract and the medial amygdala does not influence the intake of these fluids and c) BN (5-5 0 ng/rat) injected into the paraventricular nucleus does not influence the intake of water and 5% sucrose but potently inhibits that of 2% N aCl. We concluded that the inhibitory effect elicited on salt intake b y intracranial administration of BN is selective for this behaviour an d is not the expression of an aspecific depression of ingestive behavi our. (C) 1998 Elsevier Science Inc.