Abstract
Humoral (H) endorphin, a novel endogenous opioid ligand detected in brain, blood and cerebrospinal fluid was tested in a series of opiate sensitive assays. H-endorphin displaced radiolabeled enkephalin from its specific bindings sites and inhibited the electrically evoked contraction of the guinea pig ileum and mouse vas deferens. When injected to unanesthesized animals, humoral endorphin induced analgesia in rats and mydriasis in mice. The activity of H-endorphin both in vitro and in vivo attests to its opioid nature. However, while its antinociceptive effect was blocked by naloxone, mydriasis induced by H-endorphin was resistant to the effect of the opiate antagonist. Similarly, intermediate concentrations of naloxone inhibited the effect of H-endorphin on the guinea pig ileum while its effect on the mouse vas deferens was completely refractory to naloxone. The physiological function of humoral endorphin in various naturally occuring states that show similar paradoxical interactions with naloxone is discussed.
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.
