Tail-pinch elicited eating in rats (Rattus norvegicus) and hamsters (Mesocricetus auratus)

Noninjurious tail-pinch (TP) elicited a normal hyperphagic reaction to a milk solution in sated rats but did not increase the amount of milk solution consumed by sated hamsters. In both rats and hamsters, TP did increase the rate of eating, but did not change the amount of time spent contacting the drinking spout in rats and actually decreased the amount of time spent contacting the spout in hamsters. These results suggest that (1) the failure of hamsters to increase meal size in response to food deprivation is also generalizable to TP-induced eating, and (2) TP-induced hyperphagia may be caused by the generalized energizing effect that TP has on ongoing behavior rather than by TP stimulation enhancing the releasing properties of environmental stimuli such as the drinking spout.