α-Melanocyte-stimulating hormone (α-MSH) appears to play a tonic inhibitory role in feeding and energy storage. MTII, a specific synthetic MC3-R/MC4-R agonist, has similar effects on feeding in rats. The current studies demonstrate that PVN administration of α-MSH or MTII decreases nocturnal and NPY-stimulated food intake without causing aversive effects. Co-administration with NPY of 600 pmol α-MSH or 1 pmol MTII into the PVN caused a significant decrease in NPY-induced feeding. PVN administration of MTII or α-MSH at doses effective to suppress feeding did not cause conditioned taste aversion (CTA). ICV administration of α-MSH, however, did cause weak CTA. These results indicate that the potent effects on feeding of MC3-R and MC4-R agonists when injected into the PVN are not due to aversive effects.
Bibliographical noteFunding Information:
This research was supported by the General Research Funds of the Veterans Administration Medical Center and by the Minnesota Obesity Center (NIDDK-DK 50456).
- Conditioned taste aversion
- Food intake
- Melanocortin-4 receptor (MC4-R)
- Neuropeptide Y (NPY)
- Paraventricular nucleus of the hypothalamus (PVN)
- α-melanocyte-stimulating hormone (α-MSH)