The Possible Facilitatory Role of the Rostral Periventricular Preoptic Area in Secretion of Prolactin During Pseudopregnancy in the Rat

Abstract

A lesion made in the rostral periventricular region of the basal preoptic area (POA) effectively interrupted reserpin-induced pseudopregnancy in rats. However, lesions in the dorsal POA, lateral POA, nucleus and diagonal band of Broca or nucleus accumbens failed to interrupt pseudopregnancy. This suggests that the rostral periventricular POA may play a facilitatory role in regulating prolactin release during pseudopregnancy. In the rats with the lesions in the rostral periventricular POA, the interruptive effect of the lesions was reversed by daily injections of a-methyl-p-tyrosine, an inhibitor of catecholamine synthesis. Treatment with 5-hydroxy-tryptophan was also effective in maintaining pseudopregnancy in the animals bearing the rostral periventricular POA lesions. These results suggest the possible involvement of serotonergic neurons in suppressing prolactin inhibiting activity, which is mediated by dopamine neurons in the medial basal hypothalamus.