Premium
Calcium oscillations in interstitial cells of the rabbit urethra
Author(s) -
Johnston L.,
Sergeant G. P.,
Hollywood M. A.,
Thornbury K. D.,
McHale N. G.
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2004.078097
Subject(s) - ryanodine receptor , biophysics , chemistry , calcium , inositol , intracellular , endocrinology , medicine , receptor , biochemistry , biology , organic chemistry
Measurements were made (using fast confocal microscopy) of intracellular Ca 2 + levels in fluo‐4 loaded interstitial cells isolated from the rabbit urethra. These cells exhibited regular Ca 2 + oscillations which were associated with spontaneous transient inward currents recorded under voltage clamp. Interference with d ‐ myo ‐inositol 1,4,5‐trisphosphate (IP 3 ) induced Ca 2 + release using 100 μ m 2‐aminoethoxydiphenyl borate, and the phospholipase C (PLC) inhibitors 2‐nitro‐4‐carboxyphenyl N , N ‐diphenylcarbamate and U73122 decreased the amplitude of spontaneous oscillations but did not abolish them. However, oscillations were abolished when ryanodine receptors were blocked with tetracaine or ryanodine. Oscillations ceased in the absence of external Ca 2 + , and frequency was directly proportional to the external Ca 2 + concentration. Frequency of Ca 2 + oscillation was reduced by SKF‐96365, but not by nifedipine. Lanthanum and cadmium completely blocked oscillations. These results suggest that Ca 2 + oscillations in isolated rabbit urethral interstitial cells are initiated by Ca 2 + release from ryanodine‐sensitive intracellular stores, that oscillation frequency is very sensitive to the external Ca 2 + concentration and that conversion of the primary oscillation to a propagated Ca 2 + wave depends upon IP 3 ‐induced Ca 2 + release.