The role of dopamine in XXXX of the ventral tegmental area.

@entity932 @entity4925 @entity75 @entity3829 @entity35 @entity4926 @entity2955
The role of dopaminergic (DA) neurons in brain stimulation reward produced by electrical stimulation of the ventral tegmental area (VTA) was investigated in the @entity35 . In the first experiment, extensive @entity2955 lesions of the ascending fibers of the mesotelencephalic DA projections resulted in significant changes in @entity932 ( @entity932 ) rate-current intensity functions when the lesion was ipsilateral to the stimulating electrode. Similar @entity75 had no effect on these functions, thus ruling out lesion-induced performance deficits as being responsible for the decreases in @entity932 rates across the wide range of current intensities that occurred after the @entity75 . In the second experiment, @entity932 obtained from electrodes in the VTA resulted in significant increases in the DA metabolites, @entity4925 ( @entity4925 ) and @entity4926 ( @entity3829 ) in the striatum, nucleus accumbens, and olfactory tubercle ipsilateral to the stimulating electrode. The ratios of @entity4925 and @entity3829 to DA, considered to be indices of DA utilization, were also increased in these brain regions ipsilateral to the electrode. No changes were observed in the contralateral striatum, nucleus accumbens, and olfactory tubercle. Similar increases were observed in stimulated "yoked" animals that received brain stimulation at identical rates and currents but did not lever-press for this stimulation. The third experiment examined the effects of lever-pressing for food on an FR8 schedule of reinforcement on DA utilization in the striatum, nucleus accumbens, and olfactory tubercle. Despite high rates of responding, no effects were observed on @entity4925 :DA or @entity3829 :DA ratios in these brain regions.(ABSTRACT TRUNCATED AT 250 WORDS)
