Behavioral effects of diltiazem injected into the paraventricular nucleus of the hypothalamus.

The calcium channel inhibitor diltiazem is widely used as a medication for cardiovascular diseases. Some side effects have been reported after its administration, including changes in activity (apathy or hyperactivity) and feeding behavior (anorexia). Previous experiments have found that local administration of various peptides into the paraventricular nucleus of the hypothalamus can have profound effects on these two behaviors. In the present study, effects of local infusions of diltiazem into the paraventricular nucleus on locomotor activity and food intake have been tested. A marked hyperactivity, greater than the hyperactivity caused by intraperitoneal injection of amphetamine was produced. Feeding behavior was not affected one hour after the infusions but intraventricular diltiazem infusions decreased feeding behavior. It is concluded that the paraventricular nucleus of the hypothalamus has an important role in the regulation of locomotor activity and that diltiazem can act at this level to produce behavioral changes.