Antisense mRNA for NPY-Y1 receptor in the medial preoptic area increases prolactin secretion

RESUMO

We investigated the participation of neuropeptide Y-Y1 receptors within the medial preoptic area in luteinizing hormone, follicle-stimulating hormone and prolactin release. Four bilateral microinjections of sense (control) or antisense 18-base oligonucleotides of messenger ribonucleic acid (mRNA) (250 ng) corresponding to the NH2-terminus of the neuropeptide Y1 receptor were performed at 12-h intervals for two days into the medial preoptic area of ovariectomized Wistar rats (N = 16), weighing 180 to 200 g, treated with estrogen (50 µg) and progesterone (25 mg) two days before the experiments between 8.00 and 1000 a.m. Blockade of Y1 receptor synthesis in the medial preoptic area by the antisense mRNA did not change plasma luteinizing hormone or follicle-stimulating hormone but did increase prolactin from 19.6 + or - 5.9 ng/ml in the sense group to 52.9 + or - 9.6 ng/ml in the antisense group. The plasma hormones were measured by radioimmunoassay and the values are reported as mean + or - SEM. These data suggest that endogenous neuropeptide Y in the medial preoptic area has an inhibitory action on prolactin secretion through Y1 receptors