Effect of cyclo(leucyl-glycine) on [3H]spiroperidol binding in the corpus striatum and hypothalamus of spontaneously hypertensive rats.

Spontaneously hypertensive rats were found to have a greater density of specific [3H]spiroperidol binding sites in the corpus striatum and hypothalamus when compared to the normotensive Wistar-Kyoto rats. The apparent dissociation constant (Kd) for [3H]spiroperidol binding in the two groups of rats did not differ. Chronic administration of cyclo(leucyl-glycine), an analog derived from the hypothalamic peptide, melanotropin release inhibiting factor, decreased the enhanced number of [3H]spiroperidol binding sites in the striatum and hypothalamus of the hypertensive rats. These results further suggest that cyclo(leucyl-glycine) interacts with brain dopamine receptors, and that brain dopamine receptors may be involved in the etiology of hypertension.