Lateralized hunger: ipsilateral attenuation of cortical spreading depression-induced feeding after unilateral 6-OHDA injection into the substantia nigra.

Unilateral injections of 6-hydroxydopamine into the substantia nigra in the rat significantly attenuated cortical spreading depression (CSD)-induced eating from the hemisphere ipsilateral but not contralateral to the lesion. The lateralized decrease in elicited feeding was correlated with postlesion body weight loss, striatal catecholamine depletion (dopamine, 94%; norepinephrine, 52%) and amphetamine-induced ipsilateral turning, and can be characterized as an inability of the lesioned nigrostriatal system to maintain the CSD-elicited response rather than a failure to induce it. The interhemispheric control procedure allows us to exclude various general sensory and motor deficits to account for the decrement of feeding, and to attribute the feeding deficit to a reduced nigrostriatal transmission. It is suggested that CSD-induced feeding is due to an activation of integrative sensorimotor systems (especially the nigrostriatal dopamine system), rather than to homeostatic imbalances.