Effect of ventral noradrenergic bundle lesions on concentrations of monoamine neurotransmitters and metabolites in several discrete areas of the rat brain.

1. The effects of radiofrequency lesions of the ventral noradrenergic bundle (VNB) on monoamine and metabolite concentrations in several discrete areas of the rat hypothalamus were examined. Monoamines and metabolites were analyzed utilizing high-performance liquid chromatography coupled with electrochemical detection. 2. VNB lesions decreased the concentrations of norepinephrine (NE) and 3-methoxy-4-hydroxyphenylethylene glycol in all areas examined except in the ventromedial nucleus (VMN). Dopamine and 3,4-dihydroxyphenylacetic acid concentrations were selectively decreased in the dorsomedial nucleus (DMN) and also slightly decreased in the medial forebrain bundle following VNB lesions. Serotonin and 5-hydroxyindole-3-acetic acid concentrations were not altered by VNB lesion in any area examined. 3. The results indicate that the NE innervation to the hypothalamus is extensive and that NE in the VMN may not be derived from the VNB. The source of the DA innervation to the DMN may be located in or pass through the area affected by the VNB lesion.