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Sodium-replete pigeons drink excess 3% NaCl following concurrent treatment with both i.m. deoxycorticosterone acetate and pulse i.c.v. (p.i.c.v.) angiotensin II. This is not just a consequence of the water intake induced by p.i.c.v. angiotensin II, since the tachykinin eledoisin, given at equidipsogenic dose, does not evoke intake of salt. On the other hand, salt intake is not aroused in the sodium replete pigeon by continuous i.c.v. (c.i.c.v.) infusion of hyperosmotic mannitol (0.7 m ) and c.i.c.v. infusions of hyperosmotic NaCl (0.3 m ) or mannitol have no effect on the salt intake of the sodium deplete pigeon, or have effects that are unrelated to brain sodium. The salt appetite of the pigeon, like that of the rat, is evoked by an angiotensin and aldosterone synergy, and the angiotensin/aldosterone mechanism may be the general vertebrate theme of this behavior.

Neuropeptide S (NPS) is a recently identified 20 aminoacid peptide widely distributed in the brain. NPS receptors are highly expressed in the amygdala, thalamus, hypothalamus and in cortical areas. Recently, NPS has been shown to reduce voluntary food intake in food-deprived rats. The present study evaluated the effect of NPS on palatable food consumption. Male Wistar rats were trained to consume sweetened mesh palatable food 60 min a day twice a week. Drug testing begun after stable baseline of palatable food consumption was established (4–6 presentation). NPS (0.0, 0.1, 0.3, 1.0 and 3.0 nmol/rat) was administered into the lateral cerebroventricle (ICV) 10 min before access to palatable food, and food intake was monitored 15, 30 and 60 min later. Results showed a significant inhibition of food consumption for the entire period of observation (p p

The tachykinins, eledoisin and physalaemin, given by intracerebroventricular (i.c.v.) injection have been shown to be potent antidipsogenic agents in rats. To evaluate their selectivity of action on rat ingestive behaviors, we compared their effects following i.c.v. injection on the intake of water, of milk containing 3·5 or 15% fat, and of solid food. The two tachykinins inhibited water intake induced by i.c.v. angiotensin II or by cellular dehydration, but did not reduce the intake of 15% fat milk or of solid food. The intake of 3·5% fat milk was inhibited only by the highest dose (1000 ng/rat) of eledoisin which also increased grooming and locomotion. The present findings suggest that in adult rats central eledoisin and physalaemin exert a selective suppressive effect on drinking behavior without affecting feeding.