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09:34
Applications of Spatio-temporal Mapping and Particle Analysis Techniques to Quantify Intracellular Ca2+ Signaling In Situ
Published on: January 7, 2019
Spontaneous Ca2+ waves in rabbit corpus cavernosum: modulation by nitric oxide and cGMP
Gerard P Sergeant1, Michael Craven2, Mark A Hollywood1
1Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland.
The Journal of Sexual Medicine
|January 14, 2009
Summary
Nitric oxide (NO) inhibits spontaneous calcium oscillations in corpus cavernosum smooth muscle cells, providing a new mechanism for detumescent tone regulation and erectile function. This finding advances understanding of penile physiology.
Area of Science:
- Physiology
- Molecular Biology
- Urology
Background:
- Detumescent tone and relaxation by nitric oxide (NO) are crucial for penile erectile state.
- Mechanisms of penile tone regulation are not fully understood.
- Existing theories suggest sustained high cytosolic Ca(2+) levels, but Ca(2+) oscillations are an alternative possibility.
Purpose of the Study:
- To investigate spontaneous Ca(2+) oscillations in corpus cavernosum smooth muscle cells.
- To determine if NO regulates these Ca(2+) oscillations.
Main Methods:
- Isolated rabbit corpus cavernosum smooth muscle cells and tissue slices were used.
- Intracellular Ca(2+) was measured using fluo-4AM and confocal imaging.
- Patch clamp recordings assessed spontaneous membrane currents.
Main Results:
- Spontaneous Ca(2+) waves were observed in isolated smooth muscle cells, associated with inward currents.
- These waves depended on sarcoplasmic reticulum Ca(2+) stores and were blocked by specific agents.
- NO donors, YC-1, 8-bromo-cGMP, and sildenafil inhibited Ca(2+) waves.
- Regular Ca(2+) oscillations preceding contraction were seen in tissue slices and inhibited by sildenafil, indicating NO regulation.
Conclusions:
- Spontaneous Ca(2+) oscillations in corpus cavernosum smooth muscle cells are a key factor in detumescent tone.
- Nitric oxide (NO) inhibits these Ca(2+) oscillations.
- This study provides a novel understanding of detumescent tone and its NO-mediated regulation.
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