[Lysergic acid diethylamide blockade of the brain serotoninergic receptors prevents the facilitating effect of phenamine on self-stimulation in rats with destruction of the medial prefrontal cortex].

Amphetamine (1 mg/kg) increased the rate of pedal self-stimulation of the lateral hypothalamus of Wistar rats in Skinner box by 37%. Lesion of the medial prefrontal cortex with kainic acid (16 mcg/kg in 8 mcl) 10-14 days prior to the experiment did not prevent facilitating effect of amphetamine on self-stimulation. Lysergic acid diethylamid (10 mcg/kg) did not influence self-stimulation response in rats with damaged medial prefrontal cortex, but after its preliminary administration prevented the stimulating effect of amphetamine on self-stimulation of the lateral hypothalamus. The findings are discussed from two points of view: 1) the phenomenon observed is associated with the existence of hypothalamic autoregulatory dopaminergic system which provides realization of self-stimulation; 2) modulating influence of the medial prefrontal cortex on the lateral hypothalamus is mediated not only by dopaminergic but also by serotoninergic axons. It is suggested that both mechanisms may underlie the phenomenon under study.