title: Nitric oxide inhibits ACh-induced intracellular calcium oscillations in porcine tracheal smooth muscle.
abstract: With real-time confocal microscopy, the effect of three nitric oxide (NO) donors, S-nitroso-N-acetylpenicillamine, S-nitrosoglutathione, and diethylamine NO adduct, on the dynamic intracellular Ca2+ concentration ([Ca2+]i) response of porcine tracheal smooth muscle (TSM) cells to acetylcholine (ACh) was examined. ACh initiated propagating [Ca2+]i oscillations in TSM cells, which were inhibited by NO donors. 8-Bromoguanosine 3',5'-cyclic monophosphate slowed the frequency of [Ca2+]i oscillations but did not completely inhibit oscillations, suggesting that the effects of NO donors are only partially mediated via guanosine 3',5'-cyclic monophosphate-dependent mechanisms. After preexposure to NO donors, ACh induced a small biphasic [Ca2+]i response that was blocked by nifedipine, suggesting a lack of effect on Ca2+ influx through voltage-gated channels. In addition, NO donors did not inhibit Ca2+ influx induced by BAY K 8644. The [Ca2+]i response to caffeine was inhibited by NO donors, indicating inhibition of sarcoplasmic reticulum (SR) Ca2+ release. When Ca2+ influx and SR Ca2+ reuptake were blocked, basal [Ca2+]i increased, and this was inhibited by NO donors, suggesting enhanced Ca2+ efflux. These results indicate that NO donors inhibit [Ca2+]i oscillations by blocking SR Ca2+ release and enhancing Ca2+ extrusion.
authors.affiliation: Department of Anesthesiology, Mayo Foundation, Rochester, Minnesota 55905, USA.
authors.forename: Y S
authors.initials: YS
authors.lastname: Prakash
authors.forename: M S
authors.initials: MS
authors.lastname: Kannan
authors.forename: G C
authors.initials: GC
authors.lastname: Sieck
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013552:Swine; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D006152:Cyclic GMP; D000109:Acetylcholine; D002118:Calcium