title: A double perfusion system with two-channel recording for the simultaneous study of the contractile responses of the circular and longitudinal smooth muscle layers of the rat vas deferens.
abstract: A device for double perfusion of the vas deferens externally and through the lumen is described in detail. The perfusion system allows the simultaneous recording of drug-induced or spontaneous contractions of the circular and longitudinal smooth muscle layers of the organ. Isometric contractions of the longitudinal (external) layer are recorded through a tension transducer. The contractions of the circular (internal) smooth muscle layer are recorded as changes of the pressure of internal perfusion. Therefore, four different effects can be recorded for a given concentration of agonist by combining the variables related to the route of perfusion (external or internal) and type of muscle (longitudinal or circular). In addition, antagonism or synergism can be studied by simultaneously perfusing a second drug. Results can be expressed as single records or as mean concentration-response curves from which drug-receptor parameters can be directly or indirectly obtained. The importance of employing this method for the analysis of some less usual problems related to the mechanism of drug action is discussed.
authors.affiliation: Department of Pharmacology, Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Jurkiewicz
authors.forename: A
authors.initials: A
authors.lastname: Caricati-Neto
authors.forename: A R
authors.initials: AR
authors.lastname: Brito
authors.forename: S S
authors.initials: SS
authors.lastname: Mulford
authors.forename: P A
authors.initials: PA
authors.lastname: Busatto
mesh_terms: D000818:Animals; D001464:Barium / Q000494:pharmacology*; D017609:Barium Compounds; D002712:Chlorides; D004305:Dose-Response Relationship, Drug; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology*; D010477:Perfusion / Q000295:instrumentation / Q000379:methods*; D051381:Rats; D011919:Rats, Inbred Strains; D011955:Receptors, Drug / Q000187:drug effects*; D012964:Sodium / Q000494:pharmacology*; D014649:Vas Deferens
chemical_list: D017609:Barium Compounds; D002712:Chlorides; D011955:Receptors, Drug; C024986:barium chloride; D001464:Barium; D012964:Sodium; D009638:Norepinephrine