Cholecystokinin octapeptide (CCK) injected into the medial hypothalamus of the rat has been reported to suppress feeding. In this species, the superior lateral parabrachial subnucleus, which predominantly innervates the ventromedial nucleus of the hypothalamus, is composed primarily of CCK-immunoreactive neurons. Combined retrograde tracing using fluorescent dyes and immunofluorescence for CCK confirms that 80-90% of the neurons in the superior lateral parabrachial nucleus which innervate the ventromedial nucleus of the hypothalamus are CCK-positive. This pathway may underlie autonomic regulation of feeding behavior.