To clarify the effect of acetylcholinesterase (AChE) on the pathogenesis of airway hyperresponsiveness, AChE activities in tracheal smooth muscle and lung tissue from congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs were compared. For this purpose, AChE activities were determined by measuring the rate of absorbance of tissue homogenate. Relative amounts ...

Trichloroethylene (TCE) and perchloroethylene (PERC) have been reported to induce respiratory complications such as airway hyperactivity and asthma. The present study was designed to investigate their influence on smooth muscle contraction and epithelial release of prostanoids in swine trachea. Results showed that TCE and PERC exposure did not alter the basal tone of tracheal smooth muscle. How...

It is well known that histamine produces constriction via H1 receptors and decreases tracheal smooth muscle tone via H2 and H3 receptors. In addition, it has already been reported that 3-methylhistamine and phenylethylamine are competitive antagonists of histamine N-methyl-transferase (HMT), the enzyme responsible for rapid inactivation of histamine. Our results suggest the possibility that 3me...

The intracellular scaffold protein IQGAP1 supports protein complexes in conjunction with numerous binding partners involved in multiple cellular processes. Here, we determined that IQGAP1 modulates airway smooth muscle contractility. Compared with WT controls, at baseline as well as after immune sensitization and challenge, Iqgap1-/- mice had higher airway responsiveness. Tracheal rings from Iq...

Purified smooth muscle myosin light chain can be phosphorylated at multiple sites by myosin light chain kinase and protein kinase C. We have determined the sites phosphorylated on myosin light chain in intact bovine tracheal smooth muscle. Stimulation with 10 microM carbachol resulted in 66 +/- 5% monophosphorylated and 11 +/- 2% diphosphorylated myosin light chain after 1 min, and 47 +/- 4% mo...

Cooling intrathoracic airways by filling the pulmonary circulation with cold blood alters pulmonary mechanoreceptor discharge. To determine whether this initiates reflex changes that could contribute to airway obstruction, we measured changes in tracheal smooth muscle tension and bronchial arterial flow evoked by cooling. In nine chloralose-anesthetized open-chest dogs, the right pulmonary arte...

To investigate whether efferent parasympathetic fibers to the tracheal smooth muscle course through the pararecurrent nerve rather than the recurrent or the superior laryngeal nerve, we stimulated all three nerves in anesthetized dogs. We also recorded the pararecurrent nerve activity response to bronchoconstrictor stimuli and compared it with pressure changes inside a saline-filled cuff of an ...

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...

The contractile activation of airway smooth muscle tissues stimulates actin polymerization, and the inhibition of actin polymerization inhibits tension development. Actin-depolymerizing factor (ADF) and cofilin are members of a family of actin-binding proteins that mediate the severing of F-actin when activated by dephosphorylation at serine 3. The role of ADF/cofilin activation in the regulati...

The ethnomedicinal uses of the aqueous leaf extract of Andrographis paniculata Nees (AP) include treatment of pain and inflammation, malaria, asthma and common cold. We designed this study to characterize some effects of AP and those of its andrographolide constituent. Guinea pig tracheal rings suspended in organ baths containing PSS were precontracted with histamine or carbachol and then expos...