Central administration of prolactin-releasing peptide stimulates oxytocin release in rats

• Published in: Neuroscience letters Vol. 276; no. 3; pp. 193 - 196
• Main Authors: Maruyama, Minoru, Matsumoto, Hirokazu, Fujiwara, Ken, Noguchi, Jiro, Kitada, Chieko, Hinuma, Shuji, Onda, Haruo, Nishimura, Osamu, Fujino, Masahiko, Higuchi, Takashi, Inoue, Kinji
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 10.12.1999; Elsevier
• Subjects: Animals; Biological and medical sciences; Brain; Brain - physiology; Female; Fundamental and applied biological sciences. Psychology; Hormones and neuropeptides. Regulation; Hypothalamic Hormones - administration & dosage; Hypothalamic Hormones - pharmacology; Hypothalamus; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Injections, Intraventricular; Magnocellular neuron; Male; Neuropeptides - administration & dosage; Neuropeptides - pharmacology; Oxytocin; Oxytocin - blood; Oxytocin - metabolism; Prolactin-Releasing Hormone; Prolactin-releasing peptide; Rat; Rats; Rats, Wistar; Sex Characteristics; Vasopressin; Vasopressins - blood; Vertebrates: endocrinology; Brain; Magnocellular neuron; Rat; Oxytocin; Prolactin-releasing peptide; Hypothalamus; Vasopressin; Prolactin releasing hormone; Rodentia; Central nervous system; Neuropeptide; Hypothalamic hormone; Vertebrata; Mammalia; Release; Brain (vertebrata)
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(99)00831-9

The prolactin-releasing peptide (PrRP) is a novel hypothalamic peptide that has been purified as a ligand of an orphan receptor which is expressed in pituitary cells, and is known to stimulate prolactin release both in vitro and in vivo. We previously determined the immunocytochemical localization of PrRP neurons in the rat brain and our results suggest that PrRP takes part in a variety of brain functions. Additionally, in rats we have demonstrated the synaptic contact of PrRP neurons with oxytocin cell bodies in the paraventricular hypothalamic nucleus (PVH) and supraoptic nucleus (SON). This observation indicates that PrRP may regulate oxytocin secretion. In the present study, we performed intra-cerebroventricular administration of PrRP to conscious rats, and examined the effect of PrRP on the plasma levels of oxytocin and vasopressin. Our results show that central administration of PrRP increased the plasma oxytocin and vasopressin levels in female rats, but in male rats only oxytocin was increased. These results suggest that the PrRP acts as a neuro-modulator of the function of magnocellular neurons, especially oxytocin neurons, in the brain.