Leptin, the hypothalamus and the regulation of adiposity

The hypothalamus contains a wealth of peptide and non-peptide neurotransmitters, many of which have been shown experimentally to influence feeding behaviour and energy metabolism. Regulatory activities as complex as these are likely to be controlled by numerous neurotransmitters interacting at a variety of levels. The hierarchy of command of these neuronal circuits is not known, but it is possible that some converge on to a final common pathway, governed by the actions of a single neurotransmitter, through which all other influences ultimately operate. This review will discuss several of the more recently identified neurotransmitters and consider their validity as candidates in the regulation of energy homeostasis.