title: Effects of noradrenaline on the isolated human bronchus. Comparison with the isolated guinea pig trachea.
abstract: The pharmacodynamic activity of noradrenaline was evaluated comparatively in vitro on isolated human bronchi and on guinea pig tracheal spirals. Noradrenaline exerted a contractile effect on both preparations under resting tone and in the presence of propranolol 10(-6) M; maximal noradrenaline-induced contraction was 15-20% of maximal acetylcholine (ACh)-induced contraction. Without propranolol, the contractile effect of noradrenaline was negligible when the preparations were under resting tone and absent when they were precontracted with ACh. In contrast, noradrenaline exerted a strongly relaxant effect on both human bronchi (-log ED50 5.24 +/- 0.17; N = 5) and guinea pig tracheae (-log ED50 6.15 +/- 0.29; N = 8). With maximal contraction induced by ACh 3.10(-3) M the -log ED50 of both preparations were shifted to the right by functional antagonism and became 4.72 +/- 0.17 and 5.31 +/- 0.11, respectively. The pKD values of noradrenaline, calculated according to Furchgott and Bursztyn (1967), were 4.79 +/- 0.04 in human bronchi (N = 5) and 4.77 +/- 0.16 in guinea-pig tracheae (N = 8). In the presence of cocaine plus phenoxybenzamine these values were not significantly modified in human bronchi and only slightly modified in guinea pig tracheae. It is concluded that noradrenaline induces a strong beta-adrenergic response and a negligible alpha-adrenergic response from both human bronchi and guinea pig tracheae in vitro.
authors.affiliation: Faculté de Médecine Paris-Ouest, Laboratoire de Pharmacologie, France.
authors.forename: E
authors.initials: E
authors.lastname: Naline
authors.forename: C
authors.initials: C
authors.lastname: Advenier
authors.forename: R
authors.initials: R
authors.lastname: Matran
authors.forename: H
authors.initials: H
authors.lastname: Bakdach
authors.forename: L
authors.initials: L
authors.lastname: Toty
mesh_terms: D000818:Animals; D001980:Bronchi / Q000032:analysis / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010643:Phenoxybenzamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000032:analysis; D014132:Trachea / Q000032:analysis / Q000187:drug effects*
chemical_list: D011943:Receptors, Adrenergic, beta; D010643:Phenoxybenzamine; D011433:Propranolol; D003042:Cocaine; D009638:Norepinephrine