[A comparison of the effects of dopamine agonists on self-stimulation of the hypothalamus with destruction of the mesolimbic brain structures in rats raised under conditions of social isolation].

In rats bred in groups or under conditions of social isolation, amphetamine administration did not change significantly the basic rate of hypothalamic self-stimulation. The unilateral lesions of ventral tegmental area and medial prefrontal cortex in the early ontogeny (on the 17th day after birth) increased the sensitivity to amphetamine only in isolated rats. Apomorphine, the dopamine receptor agonist, in the dose which mainly affected the presynaptic receptors (0.05 mg/kg) inhibited self-stimulation by 21-23% both in grouped and socially isolated rats. Destruction of the ventral tegmental area did not change, but that of the medial prefrontal cortex doubled the sensitivity of isolated rats to apomorphine. It is suggested that the hypersensitivity of presynaptic dopamine receptors in the mesocorticolimbic system develops as a result of partial sensory and full intraspecies isolation in rats.