To assess effects of smooth muscle energy state and intracellular pH (pH(i)) on pulmonary arterial tone during hypoxia, we measured ATP, phosphocreatine, P(i), and pH(i) by (31)P-NMR spectroscopy and isometric tension in phenylephrine-contracted rings of porcine proximal intrapulmonary arteries. Hypoxia caused early transient contraction followed by relaxation and late sustained contraction. En...

ketotifen is a benzocycloheptathiophene with a range of pharmacological activities. the present study was carried out to evaluate the action of ketotifen on isolated rat bladder contractions induced by kci and acetylcholine, compared with the effects of other drugs. ketotifen (5 µm) reduced the response to acetylcholine on rat isolated bladder without altering the maximum response and shifted t...

BACKGROUND Because exposure to low temperature can modify the effect of volatile anesthetics on airway smooth muscle contraction, this study was conducted to investigate low-temperature modifications of the inhibitory effects of isoflurane and sevoflurane on canine tracheal smooth muscle tone by simultaneously measuring the muscle tension and intracellular concentration of Ca2+ ([Ca2+]i) and by...

In vascular smooth muscles, neurotransmitters or autacoids produce contraction through activation of Ca2(+)-influx and release of Ca2+ from intracellular store sites. These agonists appear to activate Ca2(+)-influxes in both voltage-dependent and voltage-independent manners. The release of Ca2+ is though to be linked to the action of inositol 1,4,5-trisphosphate. The phosphorylation of myosin l...

BACKGROUND We previously reported that the supratarsal Mueller's muscle is innervated by both sympathetic efferent fibers and trigeminal proprioceptive afferent fibers, which function as mechanoreceptors-inducing reflexive contractions of both the levator and frontalis muscles. Controversy still persists regarding the role of the mechanoreceptors in Mueller's muscle; therefore, we clinically an...

BACKGROUND Opioid induced bowel dysfunction is the most common side effect of preoperatively administrated morphine, fentanyl and its derivative. However, the influence of dezocine on intestinal mobility is rarely reported. This study was designed to investigate the effects of dezocine, morphine and sufentanil on both intestinal smooth muscle contraction and propulsion in rats. METHODS Contra...

Inhalational insulin was withdrawn from the market due to its potential to produce airway hyper-reactivity and bronchoconstriction. So the present study was designed to explore the acute effects of insulin on airway reactivity of guinea pigs and protective effects of salbutamol and ipratropium against insulin induced airway hyper-responsiveness on isolated tracheal smooth muscle of guinea pig. ...