Locus coeruleus noradrenergic lesions attenuate intraoral intake

I.p. injections of DSP-4 in male rats decreased norepinephrine (NE) levels to varying degrees throughout the brain with 66.7% reductions in the hypoth alamic paraventricular nucleus. Intake of intraorally infused sucrose was r educed for 14 days but daily pellet intake recovered within 5 days post-inj ection. Intraventricular NE restored intraoral sucrose intake in DSP-4-lesi oned rats without affecting controls. Intraventricular infusion of neuropep tide Y (NPY) reduced intraoral intake in controls but had no effect in DSP- 4-lesioned rats. NPY markedly inhibited intraoral intake in DSP-4-treated r ats that also received NE. These data confirm studies showing that NPY decr eases consummatory ingestive behavior and suggest that this inhibition invo lves ascending noradrenergic projections from locus coeruleus. NeuroReport 12:3095-3099 (C) 2001 Lippincott Williams & Wilkins.