Abstract
Blood samples were collected via jugular catheters from ovariectomized rats at 10-min intervals for 1 h before and 2 h after microinjection of 0.5 microliter of either saline vehicle or morphine sulfate (10 micrograms) into the dorsal raphe nucleus (DRN) or adjacent periaqueductal gray by means of chronically-implanted guide cannulae. Prolactin was measured by radioimmunoassay, and mean preinjection and mean postinjection values were compared for each rat (t test) as well as for each treatment group (paired t test). Neither saline in DRN nor morphine in the surrounding periaqueductal gray significantly altered circulating prolactin. A significant rise in prolactin was observed following injection of morphine into DRN. This effect of morphine was prevented by pretreatment of the animals with the narcotic antagonist naltrexone (10 mg/kg i.v.), indicating the involvement of opiate receptors. These results indicate that DRN is one site at which systemically-administered morphine might act, and suggest the possibility of participation of this mechanism in modulation of prolactin release by endogenous opioids.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
