title: Role of ryanodine receptor channels in Ca2+ oscillations of porcine tracheal smooth muscle.
abstract: Acetylcholine (ACh) induces repetitive, propagating intracellular Ca2+ concentration ([Ca2+]i) oscillations in porcine tracheal smooth muscle (TSM) cells. Using real-time confocal microscopy, we examined the role of sarcoplasmic reticulum (SR) Ca2+ release through inositol 1,4,5-trisphosphate (IP3) receptor and ryanodine receptor (RyR) channels in ACh-induced [Ca2+]i oscillations. In beta-escin permeabilized TSM cells, exposure to ACh in the presence of GTP also resulted in [Ca2+]i oscillations. [Ca2+]i oscillations could not be initiated by IP3 alone; however, an elevation of [Ca2+]i was observed. During ongoing [Ca2+]i oscillations, exposure to heparin, an IP3 receptor antagonist, caused a slowing of oscillation frequency but not complete inhibition. In contrast, ruthenium red, a RyR antagonist, completely abolished ACh-induced [Ca2+]i oscillations. Reverse transcriptase-polymerase chain reaction of TSM mRNA demonstrated the expression of RyR-2 and RyR-3 isoforms of the RyR. These results indicate that SR Ca2+ release through RyR channels is critical for ACh-induced [Ca2+]i oscillations in porcine TSM cells.
authors.affiliation: Department of Veterinary Pathobiology, University of Minnesota, St. Paul 55108, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Kannan
authors.forename: Y S
authors.initials: YS
authors.lastname: Prakash
authors.forename: T
authors.initials: T
authors.lastname: Brenner
authors.forename: J R
authors.initials: JR
authors.lastname: Mickelson
authors.forename: G C
authors.initials: GC
authors.lastname: Sieck
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D007473:Ion Channels / Q000502:physiology*; D007536:Isomerism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel; D013552:Swine; D014132:Trachea / Q000166:cytology / Q000378:metabolism*
chemical_list: D015220:Calcium Channels; D007473:Ion Channels; D009124:Muscle Proteins; D012333:RNA, Messenger; D019837:Ryanodine Receptor Calcium Release Channel; D015544:Inositol 1,4,5-Trisphosphate; D000109:Acetylcholine; D002118:Calcium