Serotonin-Induced Region-Specific Responses of the Arcuate and Ventromedial Hypothalamic Nuclei

Abstract

The arcuate nucleus (ARC) modulates both satiety and hunger signals at the lateral and medial sites, respectively, though these competing responses may be both mediated by serotonin (5-HT). We sought to determine region-specific effects of 5-HT on ARC neurons. Electrical activities in rat hypothalamic slices were simultaneously recorded with an extracellular multielectrode array. 5-HT effects on the ARC were region-specific: primary inhibition of medial ARC and stimulation of lateral ARC neurons. 5-HT primarily inhibited ventromedial nucleus neurons. These results suggest ARC region-specific responses to 5-HT consistent with the anatomical location of lateral ARC anorexigenic proopiomelanocortin neurons and medial ARC orexigenic neuropeptide Y neurons.