Biomaterial Database

Acetylcholine-induced chloride current oscillations in swine tracheal smooth muscle cells. 1996

X Liu, and J M Farley

Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, USA.

The activation of muscarinic receptors by acetylcholine (ACh) in tracheal smooth muscle cells induced Ca++ oscillations, measured as the activation of Ca(++)-dependent Cl- currents (Clca) at the K+ equilibrium potential. The currents were not abolished by replacement of external and internal K+ with Cs+ but decreased after reduction in internal Cl- concentration or extracellular application of niflumic acid, a Cl- channel blocker. The Clca oscillations were dependent on external Ca++ concentration ([Ca++]e). The mean current and frequency increased with increasing [Ca++]e, were enhanced by Bay K 8644 and were inhibited by verapamil, suggesting a role for voltage-operated Ca++ channels (VOC). Steady-state increases in Clca induced by 10(-6) M ACh could be converted to oscillations by reducing [Ca++]e or by buffering intracellular Ca++ with ethyleneglycolbis-N,N,N'-N'-tetraacetic acid (EGTA). Oscillations in Clca induced by 3 x 10(-8) and 10(-7) M ACh were more sensitive to EGTA than those induced by 10(-6) M ACh. Caffeine induced nonoscillatory, transient increases in Clca and reduced subsequent ACh-induced increases in Clca. The oscillatory patterns of Clca induced by ACh and the effects of modification of Ca++ influx were similar for oscillations in intracellular Ca++ concentration [Ca++]i as measured with confocal microfluorimetry. Thus, ACh-induced Clca oscillations reflect fluctuations in [Ca++]i that are consistent with initiation of Ca++ release from inositol-1,4,5-trisphosphate-(IP3)sensitive Ca++ stores. Maintenance of the oscillations requires Ca++ influx, in part through voltage-operated Ca++ channels.

UI	MeSH Term	Description	Entries
D007424	Intracellular Fluid	The fluid inside CELLS.	Fluid, Intracellular,Fluids, Intracellular,Intracellular Fluids
D008297	Male		Males
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D002110	Caffeine	A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.	1,3,7-Trimethylxanthine,Caffedrine,Coffeinum N,Coffeinum Purrum,Dexitac,Durvitan,No Doz,Percoffedrinol N,Percutaféine,Quick-Pep,Vivarin,Quick Pep,QuickPep
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D003592	Cytophotometry	A method for the study of certain organic compounds within cells, in situ, by measuring the light intensities of the selectively stained areas of cytoplasm. The compounds studied and their locations in the cells are made to fluoresce and are observed under a microscope.	Microfluorometry,Cytophotometries,Microfluorometries
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols