Role of cyclic ADP-ribose in the regulation of [Ca2+]i in porcine tracheal smooth muscle.
The purpose of the present study was to determine whether cyclic ADP-ribose (cADPR) acts as a second messenger for Ca2+ release through ryanodine receptor (RyR) channels in tracheal smooth muscle (TSM). Freshly dissociated porcine TSM cells were permeabilized with beta-escin, and real-time confocal microscopy was used to examine changes in intracellular Ca2+ concentration ([Ca2+]i). cADPR (10 nM-10 microM) induced a dose-dependent increase in [Ca2+]i, which was blocked by the cADPR receptor antagonist 8-amino-cADPR (20 microM) and by the RyR blockers ruthenium red (10 microM) and ryanodine (10 microM), but not by the inositol 1,4,5-trisphosphate receptor blocker heparin (0.5 mg/ml). During steady-state [Ca2+]i oscillations induced by acetylcholine (ACh), addition of 100 nM and 1 microM cADPR increased oscillation frequency and decreased peak-to-trough amplitude. ACh-induced [Ca2+]i oscillations were blocked by 8-amino-cADPR; however, 8-amino-cADPR did not block the [Ca2+]i response to a subsequent exposure to caffeine. These results indicate that cADPR acts as a second messenger for Ca2+ release through RyR channels in TSM cells and may be necessary for initiating ACh-induced [Ca2+]i oscillations.
Prakash
Y S
YS
Department of Anesthesiology, Mayo Foundation, Rochester, Minnesota 55905, USA.
Kannan
M S
MS
Walseth
T F
TF
Sieck
G C
GC
D000109:Acetylcholine / Q000494:pharmacology; D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002463:Cell Membrane Permeability; D036563:Cyclic ADP-Ribose / Q000031:analogs & derivatives; D004928:Escin / Q000494:pharmacology; D018613:Microscopy, Confocal; D009130:Muscle, Smooth / Q000378:metabolism*; D010507:Periodicity; D012430:Ruthenium Red / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects; D015290:Second Messenger Systems; D013552:Swine; D014132:Trachea / Q000378:metabolism*
D002121:Calcium Channel Blockers; D019837:Ryanodine Receptor Calcium Release Channel; D012430:Ruthenium Red; D036563:Cyclic ADP-Ribose; C082175:8-aminoadenosine cyclic 3',5'-(hydrogen phosphate) 5'-ribofuranosyl ester; D000246:Adenosine Diphosphate Ribose; D002110:Caffeine; D004928:Escin; D000109:Acetylcholine; D002118:Calcium