Effects of bambuterol and terbutaline on isolated rat’s tracheal smooth muscle

Abstract

Terbutaline (Bricanyl) and its prodrug Bambuterol (Bambec) are highly potent beta(2)-adrenoceptor agonists often used in asthma patients. Terbutaline in the form of inhaled short-acting bronchodilator relieves asthmatic symptoms. However, the effects of bambuterol given intratracheally have rarely been explored. To verify the effect of bambuterol and terbutaline, which act on the tracheal smooth muscle directly in vitro, we used our preparation to test the effects of bambuterol on isolated rat's tracheal smooth muscle compared with terbutaline. The following assessments of bambuterol and terbutaline were performed: (1) effect on tracheal smooth muscle resting tension; (2) effect on contraction caused by 10(-6) M methacholine as a parasympathetic mimetic; (3) effect of the drugs on electrically induced tracheal smooth muscle contractions. The results indicated that adding bambuterol induced a significant further contraction to 10(-6) M methacholine-induced contraction when the preparation was increased to 10(-4) M. But terbutaline elicited a relaxation response at a dose of 10(-6) M or more. Both bambuterol and terbutaline could inhibit electrical field stimulation (EFS) induced spike contraction. Terbutaline had an anti-cholinergic effect that could relieve asthmatic symptoms. But the effect of bambuterol acting on tracheal smooth muscle directly was controversial.

Antioxidants may reduce the smooth muscle-relaxing action of β2-adrenergic receptor agonists

“…As a β 2 -AR agonist, terbutaline was added to last-day-pregnant myometrial and cervical rat tissue, and to tracheal samples from estrous phase female rats in an organ bath. The responses of the tissues were in harmony with the literature data: the myometrium was relaxed, the cervical resistance was increased, and the tracheal tone was reduced (Gaspar et al 2005;Gaspar et al 2007, Chou et al 2010). In the presence of the antioxidant agents the effect of terbutaline was reduced only in the case of the trachea, while the uterine (myometrium and cervix) responses were unchanged.…”

Expression and Regulation of Thymic Stromal Lymphopoietin and Thymic Stromal Lymphopoietin Receptor Heterocomplex in the Innate–Adaptive Immunity of Pediatric Asthma

“…Therefore, the avoidance of allergens can prevent asthma development in children. Clinically, the main treatments for asthma can be divided into five broad categories: (1) steroids: corticosteroids [ 29 ], prednisone [ 30 ] and methylprednisolone (Solumedrol) [ 31 ]; (2) leukotriene modifiers: montelukast (Singulair); (3) theophylline (Xanthium) [ 32 ]; (4) bronchodilators salmeterol (Serevent) [ 33 ], albuterol (Ventolin) [ 34 ], bambuterol (Bambec) [ 35 ], fenoterol (Berotec) and terbutaline (Bricanyl); and (5) Intalinhaler: cromolyn sodium [ 36 ]. Corticosteroids, currently the most efficacious drugs used to treat asthma and respiratory irritation [ 29 ], inhibit proinflammatory protein production [ 37 ]; reduce the number of eosinophils, T lymphocytes, mast cells and DCs during respiratory inflammation [ 38 ]; and decrease the incidence of asthma and exercise-induced asthma [ 39 ].…”

α1 adrenergic receptor agonist, phenylephrine, actively contracts early rat rib fracture callus ex vivo

“…3 Seven day calluses were used for force measurement as such calluses are fibrous in nature and ideal for measurement of active force production. 3 [21][22][23][24] KH solution had the following composition (mM): NaCl 135; KCl 5; MgCl 2 3; NaH 2 PO 4 0.8; HEPES 10; calcium (Ca 2þ ) 1.2; glucose 5. Solution temperature was 228C and its stable pH was stable at 7.4 for a period of at least 6 h.…”