Background The soluble guanylyl cyclase (sGC) is expressed in airway smooth muscle, and agents that stimulate sGC activity cause airway smooth muscle relaxation and bronchodilation. BAY 41-2272 is a potent nitric oxide (NO)-independent sGC stimulator, but little is known about its effects in airway smooth muscle. Therefore, this study aimed to investigate the mechanisms underlying the relaxatio...

Exposure to ozone (O3) induces airway hyperresponsiveness mediated partly through the release of substance P (SP) from nerve terminals in the airway wall. Although substantial evidence suggests that SP is released by sensory nerves, SP is also present in neurons of airway ganglia. The purpose of this study was to investigate the role of intrinsic airway neurons in O3-enhanced airway responsiven...

The response of canine tracheal and bronchial smooth muscle to i.a. administered agonists causing smooth muscle contraction was compared in 22 mongrel dogs in vivo. Tracheal and bronchial contractile responses were measured isometrically in situ in the same dogs. In nine dogs, dose-response curves were generated with i.a. acetylcholine and histamine (10(-10) to 10(-6) mol) in a 4-cm tracheal se...

Thestimulatory effect of the extract of Portulaca oleracea (P. olerace) on β-adrenoceptor of tracheal smooth muscle was examined.To examine β-adrenoceptor stimulatory effect, concentration response curve to isoprenaline was obtained in pre-contracted tracheal smooth muscle in the presence of three concentrations of aqueous-ethanolic extract, propranolol, and saline. Values of EC50 (the effectiv...

Different pharmacological effects of Achillea millefolium including its relaxant effect on smooth muscle have been shown previously. In the present study the stimulatory effect of the plant extract on β-adrenoceptor of tracheal muscle was examined in order to investigate one possible mechanism for its observed relaxant effect. Effect of three concentrations of hydroethanol extract, 10 nM propra...

Endothelins (ETs) can modulate the airway smooth muscle tone. Using simultaneous measurements of cytosolic Ca2+ concentration ([Ca2+]i) and tension as well as the reverse transcription polymerase chain reaction (RT-PCR), we examined ET systems in the porcine trachea. In the functional study, the application of ET-1, ET-3 or sarafotoxin S6c (S6c) caused increases in [Ca2+]i and tension, in a con...

Recent studies have implicated a role for tumour necrosis factor-alpha (TNFalpha) in the development of the asthmatic reaction. In this study, we examined the influence of TNFalpha on isotonic contraction of tracheal smooth muscle of the guinea-pig in vitro in response to methacholine. Tracheal rings were incubated with recombinant human (rh)TNFalpha (3x10(-11) M) for 30 min, and concentration-...

Objective(s): Baicalein, a compound extracted from a variety of herbs, showed various pharmacological effects. This study evaluated the relaxant effects of baicalein and its underlying molecular mechanisms of action on rat’s isolated tracheal smooth muscle.Materials and Methods: Tracheal smooth muscle were contracted by 10 μM methacholin...