Adrenaline-induced anorexia acts on tail-pinch feeding in the rat

Non-injurious tail-pinching of rats induced much more milk intake than water intake, whether the fluids were offered singly or in a choice. In both the single item and choice situations i.p. injection of adrenaline in doses of 2.5 to 15 micrograms/100 g elicited a marked, dose-related inhibition of tail-pinch-induced (TPI) milk intake, but had no consistent effect on the small amount of TPI water intake. The same doses of adrenaline injected i.m. has no inhibitory effect on TPI milk intake; on the contrary, they elicited increases (although these were not statistically significant). Thus, the effects of adrenaline (probably of hepatic origin because they are produced only by i.p. injections) which inhibit feeding caused by food deprivation are also capable of inhibiting non-homeostatic feeding induced by tail-pinch in a satiated rat.