Advances in our understanding of the mechanisms underlying the develop
ment of obesity have occurred over the past few years, prompted by the
discovery of leptin and its role in modulating energy balance. The di
scovery that leptin modulates neurotransmitter pathways in the CNS and
the growing body of evidence suggesting that obesity in humans and ro
dent models is associated with leptin resistance have focused attentio
n on downstream CNS pathways. From these neurotransmitter systems, a s
eries of novel potential targets for the development of antiobesity ag
ents is emerging.