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Calcium currents in interstitial cells from the guinea-pig bladder.
1Centre for Biophotonics, University of Strathclyde, Glasgow, Scotland, UK. k.mccloskey@qub.ac.uk
BJU International
|May 12, 2006
Summary
Interstitial cells in guinea-pig bladders exhibit inward currents, primarily L-type calcium currents, with a nifedipine-resistant component sensitive to nickel ions. Further research is needed to fully characterize these unique currents.
Area of Science:
- Physiology
- Pharmacology
- Cell Biology
Background:
- Interstitial cells (IC) play a crucial role in bladder function.
- Understanding ion channel activity in IC is vital for elucidating detrusor muscle physiology.
Purpose of the Study:
- To identify and characterize inward currents in isolated guinea-pig detrusor interstitial cells.
- To investigate the pharmacological properties of these currents using patch-clamp techniques.
Main Methods:
- Whole-cell patch-clamp technique applied to enzymatically isolated guinea-pig detrusor IC.
- Inward currents were evoked by voltage steps from a holding potential of -80 mV.
- Pharmacological agents including Cs+, Ba2+, Bay K 8644, nifedipine, and Ni2+ were used to probe current characteristics.
Main Results:
- Inward currents activated above -50 mV, peaked at 0 mV, and reversed near +50 mV, exhibiting voltage-dependent inactivation.
- A window current was observed between -40 mV and +20 mV.
- The current was augmented by Ba2+ and Bay K 8644, and significantly reduced by nifedipine and Ni2+, suggesting L-type calcium channel involvement with a nifedipine-resistant component.
Conclusions:
- Guinea-pig detrusor IC possess inward currents consistent with L-type calcium currents.
- A distinct nifedipine-resistant, Ni2+-sensitive inward calcium current component was identified.
- Further investigation is required to fully elucidate the properties and role of this novel conductance.