title: Ability of L-histidine to decrease desensitization of the myometrium to epinephrine.
abstract: Experiments were performed with 62 longitudinal strips of the uterine horns from 10 nonpregnant rats. The ability of continuously infused epinephrine in high concentration (10(-6) g/ml, 30 min) to suppress spontaneous contractions due to activation of beta-adrenoceptors progressively decreased, which was associated with receptor desensitization. Histidine in a concentration of 3 x 10(-11) g/ml had no effect, while in concentrations of 3 x 10(-8), 3 x 10(-7), and 3 x 10(-6) g/ml decreased the degree of desensitization. Our results indicate that histidine not only potentiates beta-adrenoceptor activation, but also prevents the development of desensitization. These data should be taken into account during therapy with beta-adrenoceptor agonists.
authors.affiliation: Department of Normal Physiology, Kirov State Medical Academy.
authors.forename: T V
authors.initials: TV
authors.lastname: Tumanova
authors.forename: E N
authors.initials: EN
authors.lastname: Sizova
authors.forename: V I
authors.initials: VI
authors.lastname: Tsirkin
mesh_terms: D000818:Animals; D004347:Drug Interactions; D004351:Drug Resistance; D004837:Epinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006639:Histidine / Q000008:administration & dosage / Q000494:pharmacology*; D066298:In Vitro Techniques; D009215:Myometrium / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism; D014590:Uterine Contraction / Q000187:drug effects
chemical_list: D011943:Receptors, Adrenergic, beta; D006639:Histidine; D004837:Epinephrine