Related Experiment Videos
Ryanodine receptors in human bladder smooth muscle
P Chambers1, D E Neal, J I Gillespie
1Department of Surgery, Medical School, University of Newcastle upon Tyne, UK.
Experimental Physiology
|March 19, 1999
Summary
Human bladder smooth muscle expresses RyR2, a key protein for calcium release. Despite initial unresponsiveness, functional calcium-induced calcium release is confirmed in detrusor muscle cells.
Area of Science:
- Physiology
- Molecular Biology
- Urology
Background:
- Intracellular calcium (Ca2+) release role in human bladder smooth muscle activation is debated.
- Ryanodine receptors (RyRs) mediate Ca2+ release from the sarcoplasmic reticulum (SR).
Purpose of the Study:
- To investigate the expression of RyR isoforms (RyR1, RyR2, RyR3) in human detrusor smooth muscle.
- To determine the functional presence of Ca2+ release channels in these cells.
Main Methods:
- RT-PCR to detect RyR mRNA expression in isolated human detrusor smooth muscle.
- Caffeine response assays on cultured human bladder smooth muscle cells.
- Saponin-permeabilization to assess 45Ca2+ release from the SR.
Main Results:
- RyR2 mRNA was detected in all human detrusor samples; RyR1 and RyR3 mRNA were absent.
- Cultured bladder smooth muscle cells showed no response to caffeine.
- Functional Ca2+ release, sensitive to Ruthenium Red, was observed in permeabilized cells, confirming Ca(2+)-induced Ca(2+) release (CICR).
Conclusions:
- Human detrusor smooth muscle expresses RyR2, suggesting its involvement in Ca2+ signaling.
- The properties of RyR2 may be altered in cultured cells compared to freshly isolated tissue.
- Functional CICR is present in human bladder smooth muscle, with potential implications for detrusor function.