Galanin stimulates the release of vasoactive intestinal polypeptide from perifused hypothalamic fragments in vitro and from periventricular structures into the cerebrospinal fluid in vivo in the rat.
Intracerebroventricular injection of galanin (2 micrograms/rat) raised plasma prolactin (PRL) levels in the rat, which was accompanied by an increase in immunoreactive vasoactive intestinal polypeptide (VIP) in the cerebrospinal fluid (CSF). Immunoreactive VIP release from superfused rat hypothalamic fragments in vitro was dose-relatedly stimulated by galanin (10(-7) and 10(-8) M). PRL release from superfused rat anterior pituitary cells was stimulated by TRH (10(-8) M) but not affected by galanin (10(-7) to 10(-5) M). These findings indicate that central galanin has a stimulating role in the release of hypothalamic VIP, which results in pituitary PRL secretion in the rat.
D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000378:metabolism*; D019004:Galanin; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D007276:Injections, Intraventricular; D008297:Male; D010455:Peptides / Q000008:administration & dosage / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000134:cerebrospinal fluid / Q000378:metabolism*
D010455:Peptides; D014660:Vasoactive Intestinal Peptide; D013973:Thyrotropin-Releasing Hormone; D019004:Galanin; D011388:Prolactin