Leptin inhibits norepinephrine and dopamine release from rat hypothalamic neuronal endings.

Noradrenergic and dopaminergic afferents arising from the brain stem to the hypothalamus still play a poorly characterised role in food intake control. We have studied the effect of leptin, an adipocyte-derived hormone which has been implicated in the regulation of feeding behaviour, on [3H]norepinephrine and [3H]dopamine release from perfused hypothalamic neuronal endings (synaptosomes) in vitro. We have found that leptin (0.01-10 nM) does not modify basal, while it inhibits depolarization-induced norepinephrine and dopamine release. We can hypothesize that at least part of the anorectic activity of leptin in the hypothalamus is effected through an inhibition of noradrenergic and dopaminergic firing.