Abstract
Rats receiving either melanocyte-stimulating hormone (MSH) or control solution were tested in a combined active and passive avoidance task involving different visual cues and two levels of shock. The group tested at 0.8 mA had a higher (
P < 0.05) index of discrimination than the rats tested at the barely perceptible 0.4 mA. In this complex task, no effect of MSH was noted on behavior during acquisition or extinction, nor was there an effect upon adrenal or body weight. The lack of an observable action of MSH on activity as tested in the shuttle box, general activity meter, and open-field maze suggests that the previously reported influence of MSH on behavior cannot be adequately explained as a simple effect upon activity.
