ABSTRACT
The effects of dynamic and static load on the intracellular concentrations of sodium [Formula: see text] and potassium (K+i) in m. soleus and m. biceps, respectively, were studied in mice. Both dynamic (swimming for 60 min) and static (hanging on the grid for 40 min) load led to a 2-fold increase in [Formula: see text] level, a decrease in K+i concentration by 25-35%, and 3-4-fold increase in the [Formula: see text] ratio. These effects of dynamic and static loads on the studied parameters remained unchanged in mice subjected to regular physical exercise (swimming or hanging on the grid for 1 h a day over 4 weeks). Our results suggest that dissipation of sodium and potassium transmembrane gradients during physical exercise can be considered as a factor of regulation of functional activity of skeletal muscles, which includes changes in transcription and translation of myokines observed previously.
Subject(s)
Muscle, Skeletal/metabolism , Physical Conditioning, Animal/physiology , Potassium/metabolism , Sodium/metabolism , Animals , Ions/analysis , Ions/metabolism , Male , Mice , Mice, Inbred C57BL , Muscle Stretching Exercises/physiology , Muscle, Skeletal/chemistry , Potassium/analysis , Sodium/analysis , Swimming/physiology , Weight-Bearing/physiologyABSTRACT
The effect of nanopowder CoFe(2)O(4)on contractile responses of smooth-muscle segments of guinea pigs airways was studied by mechanography. Both in vivo inhalation of nanopowder aerosol or in vitro application of nanopowder to isolated airway segments increased the amplitude of contractile responses to histamine and potentiated the dilatory reaction to adrenergic salbutamol.
Subject(s)
Metal Nanoparticles/toxicity , Muscle Contraction/drug effects , Muscle, Smooth/drug effects , Respiratory Physiological Phenomena/drug effects , Administration, Inhalation , Albuterol/pharmacology , Animals , Cobalt , Guinea Pigs , Histamine/pharmacology , Metal Nanoparticles/administration & dosage , Muscle Contraction/physiology , Muscle, Smooth/physiologyABSTRACT
In guinea pigs sensitized with ovalbumin the respiratory epithelium lost its ability to modulate the responses of airway smooth muscles to histaminergic stimuli. Incubation of bronchial segments with IL-5 potentiated the contractile responses of bronchial smooth muscles to histamine in both intact and sensitized animals. Incubation of bronchial segments with IL-5 receptors moderated contractile activity of segments from sensitized pigs, but not in the segments from intact controls.
Subject(s)
Bronchi/physiology , Bronchial Hyperreactivity/physiopathology , Muscle, Smooth/physiology , Respiratory Mucosa/physiology , Animals , Bronchial Hyperreactivity/immunology , Drug Synergism , Guinea Pigs , Histamine/pharmacology , In Vitro Techniques , Interleukin-5/pharmacology , Male , Muscle Contraction/drug effects , Ovalbumin/immunologyABSTRACT
The involvement of cAMP- and cGMP-dependent signal systems into the regulation of the contractile reaction of smooth muscles of the rabbit pulmonary arteries was studied using a mechanographic method. For modulation of intracellular level of cyclic nucleotides we used adenylate cyclase activators beta-adrenoceptor agonist isadrin, guanylate cyclase inhibitor methylene blue, penetrating analog dibutyryl-cAMP, and phosphodiesterase inhibitors. The mechanisms of cAMP- and cGMP-dependent regulation of smooth muscle contractile activity were realized in close interrelationship, and the key component of this was cyclic nucleotide phosphodiesterases. The ratio of activities of phosphodiesterase subtypes in smooth-muscle cells can essentially modulate the adrenergic effects in the pulmonary artery wall and even invert them.
Subject(s)
Cyclic AMP/metabolism , Cyclic GMP/metabolism , Muscle Contraction/physiology , Muscle Tonus , Muscle, Smooth, Vascular/metabolism , Pulmonary Artery/metabolism , 1-Methyl-3-isobutylxanthine/pharmacology , Animals , Dipyridamole/pharmacology , In Vitro Techniques , Isoproterenol/pharmacology , Muscle, Smooth, Vascular/drug effects , Phosphodiesterase Inhibitors/pharmacology , Pulmonary Artery/anatomy & histology , Rabbits , Signal Transduction/physiology , Sympathomimetics/pharmacology , Theophylline/pharmacology , Vasodilator Agents/pharmacologyABSTRACT
Muscle tension recording was used to study adrenergic contractile reactions of pulmonary artery smooth muscles in rabbits. Stimulation of alpha-adrenoceptors induced contraction of pulmonary artery smooth muscle cells. Endothelium partially inhibited the contractile effect of alpha-adrenoceptor agonists. Activation of smooth muscle beta-adrenoceptors in pulmonary arteries produced a dual dose-dependent effect (relaxation at agonist concentrations of 10 nM-1 muM and contraction at concentrations above 10 muM). The contractile effect of beta-adrenoceptor activation in smooth muscle cells is a specific feature of pulmonary arteries probably related to peculiarities of cAMP-signaling in these cells.
