Food intake and body weight: effects of specific and non-specific lesions in the midbrain path of the ascending noradrenergic neurons of the rat.
Bilateral injections of 4.8 or 12 microgram of 6-hydroxydopamine hydrobromide were made in the midbrain path of the ascending norepinephrine (NE) fibers. Maximum NE depletion was obtained with the 4 microgram dose. Increasing the dose did not increase NE depletion in either the hypothalamus or the telencephalon. Increases in food intake were observed following the 12 microgram dose only. Electrolytic, copper sulfate, or 5,6-dihydroxytryptamine lesions at the same site caused increases in both food intake and body weight with only moderate (-32 to -58%) decreases in NE levels. Behavioral changes were seen in only those groups in which a large amount of non-specific tissue damage was also observed. Therefore, the behavioral effects were attributed to general tissue damage in the area and not the NE fibers specifically.