Role of ryanodine receptor channels in Ca2+ oscillations of porcine tracheal smooth muscle

MS Kannan, YS Prakash, T Brenner… - … of Physiology-Lung …, 1997 - journals.physiology.org
MS Kannan, YS Prakash, T Brenner, JR Mickelson, GC Sieck
American Journal of Physiology-Lung Cellular and Molecular …, 1997journals.physiology.org
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 …
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.
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