title: Endorphins and the central inhibition of urinary bladder motility.
abstract: The involvement of endogenous opioid mechanisms in the central neurogenic control of urinary bladder function has been examined in anesthetized rats. Intracerebroventricular (ICV) microinjections of beta-endorphin (0.5-2.0 micrograms) produced powerful inhibition of rhythmic bladder contractions initiated by central reflex activity. The peptide fragments gamma-endorphin and alpha-endorphin (4-16 micrograms), formed by the processing of beta-endorphin by membrane homogenates of brain, were less active than the parent compound. The inhibitory effects of beta-endorphin was reversed by ICV naloxone (1-2 micrograms) but higher doses were required to reverse gamma- or alpha-endorphin effects. ICV naloxone administered alone increased intravesicular pressure and bladder contraction frequency. These observations support the hypothesis that the endorphins have a physiological role in the central regulation of urinary bladder activity.
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000494:pharmacology*; D005260:Female; D009119:Muscle Contraction / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000187:drug effects; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology*; D018822:alpha-Endorphin; D001615:beta-Endorphin; D018823:gamma-Endorphin
chemical_list: D004723:Endorphins; D001615:beta-Endorphin; D018822:alpha-Endorphin; D018823:gamma-Endorphin