Characterisation of adjustments to the structure of feeding behaviour following pharmacological treatment: effects of amphetamine and fenfluramine and the antagonism produced by pimozide and methergoline.

An observational procedure for examining the micro-structure of eating has been employed to establish the characteristic behaviour patterns displayed after various pharmacological manipulations. Using a double dissociation design it was shown that amphetamine and fenfluramine gave rise to quite distinctive readjustments to the structure of feeding behaviour. Amphetamine anorexia was characterised by a long initial delay, following which feeding was typified by infrequent short bursts of rapid eating. These effects were antagonised by the dopamine receptor blocking agent, pimozide. Fenfluramine exerted a more restricted pattern of action characterised by a marked slowing of the rate of eating. This effect was countered by the serotonin receptor blocking agent methergoline. These data throw light on the way in which pharmacological agents may impede food consumption and upon the neurochemical systems believed to be involved in the expression of feeding behaviour.