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Pacemaker activity in urethral interstitial cells is not dependent on capacitative calcium entry
Eamonn Bradley1, Mark A Hollywood, Noel G McHale
1Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland.
American Journal of Physiology. Cell Physiology
|August 16, 2005
Summary
Interstitial cells (IC) in rabbit urethra exhibit capacitative calcium entry (CCE). However, this CCE pathway does not contribute to spontaneous activity in these cells.
Area of Science:
- Physiology
- Cell Biology
- Urology
Background:
- Interstitial cells (IC) play crucial roles in various tissues.
- Capacitative calcium entry (CCE) is a significant mechanism for calcium influx.
- Understanding calcium signaling in urethral IC is important for physiological function.
Purpose of the Study:
- To investigate the properties of capacitative calcium entry (CCE) in rabbit urethral interstitial cells (IC).
- To determine the role of CCE in the spontaneous activity of these cells.
Main Methods:
- Isolation of interstitial cells from the rabbit urethra.
- Measurement of calcium (Ca2+) entry using techniques assessing intracellular Ca2+ stores.
- Application of various calcium entry blockers (Gd3+, La3+, Ni2+, SKF-96365, wortmannin, nifedipine).
- Electrophysiological recordings of spontaneous transient inward currents.
Main Results:
- Calcium entry in IC was enhanced when intracellular Ca2+ stores were depleted, indicating CCE.
- Gadolinium (Gd3+), lanthanum (La3+), and nickel (Ni2+) significantly reduced CCE.
- CCE in IC was resistant to SKF-96365, wortmannin, and nifedipine.
- Spontaneous transient inward currents in IC were not significantly affected by Gd3+ or La3+ and only slightly by Ni2+.
Conclusions:
- Freshly dispersed interstitial cells from the rabbit urethra possess a functional capacitative calcium entry (CCE) pathway.
- Despite the presence of CCE, this pathway does not appear to contribute to the spontaneous electrical activity observed in these cells.