Meal patterning in rodents: psychopharmacological and neuroanatomical studies

Studies of meal patterning have made an important contribution to our understanding of ingestive behaviour. This paper initially reviews studies of normal meal patterning in rodents, with an emphasis on the determination of suitable meal criteria. Studies of serotonergic mechanisms in the control of meal size and feeding rate suggest important roles for the 5HT1B and 5-HT2C receptor. Analysis of dopaminergic mechanisms show that dopamine D2 receptor blockade is associated with enhancement of meal size and decrease of meal frequency; this probably represents a failure to switch from feeding to other behaviour when a meal is expected to terminate. Finally studies are described demonstrating that lesions of several forebrain structures, including hippocampus and nucleus accumbens, lead to a similar syndrome of short, frequent meals with little evidence of a deficit in body weight regulation. These structures may play a role in the organisation of meal patterning.