Enhanced adrenergic excitation of serotonergic dorsal raphe neurons in genetically obese rats

Neurosci Lett. 2002 Oct 31;332(2):107-10. doi: 10.1016/s0304-3940(02)00931-x.


Serotonergic neurons in the dorsal raphe nucleus (DRN) project to the ventromedial hypothalamus (VMH), where serotonin (5-HT) release modulates feeding. 5-HT release in the VMH is altered in genetically obese vs. lean Zucker rats. Serotonergic DRN neurons are subject to adrenergic and serotonergic neuromodulation. To determine if the difference in 5-HT release between lean and obese rats might be due to differences in these neuromodulatory pathways, we examined the effects of phenylephrine (PE) and 5-HT on serotonergic DRN neurons using current-clamp recording. Cells from lean and obese animals responded similarly to 5-HT, but cells from obese rats exhibited both a larger depolarization and increased firing rate in response to PE than did cells from lean rats. This indicates that DRN neurons of obese rats have an enhanced adrenergic drive.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic alpha-Agonists / pharmacology
  • Animals
  • Axons / physiology
  • Genotype
  • In Vitro Techniques
  • Male
  • Membrane Potentials / physiology
  • Neurons / physiology*
  • Obesity / genetics*
  • Obesity / physiopathology*
  • Phenylephrine / pharmacology
  • Raphe Nuclei / cytology
  • Raphe Nuclei / physiology*
  • Rats
  • Rats, Zucker
  • Serotonin / physiology*
  • Sympathetic Nervous System / physiology*
  • Ventromedial Hypothalamic Nucleus / cytology
  • Ventromedial Hypothalamic Nucleus / physiology


  • Adrenergic alpha-Agonists
  • Phenylephrine
  • Serotonin