[Des-1-tyrosine-gamma-endorphin: an assessment of its neuroleptic properties and effect on dopamine synthesis].

The neuropeptide des-1-tyrosine-gamma-endorphine (DTGE) has been shown to facilitate, similarly to neuroleptics, the extinction of pole-jumping avoidance behavior, to enhance the grasping reflex, and to produce catalepsy. In in vitro experiments, DTGE (10(-4) M) did not change the activity of solubilized rat brain striatal tyrosine hydroxylase. However at the concentration of 10(-4) M and 10(-6) M DTGE has been found to accelerate tyrosine hydroxylation in the striatal synaptosomes. It is suggested that the effect of DTGE on the brain dopamine biosynthesis might be involved in the development of the neuropeptide neuroleptic effect.