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Anoxia and corporal smooth muscle dysfunction: a model for ischemic priapism
G A Broderick1, D Gordon, J Hypolite
1Division of Urology, Hospital of the University of Pennsylvania, Philadelphia 19104.
The Journal of Urology
|January 1, 1994
Summary
Anoxia significantly impairs corporal smooth muscle function, affecting erection and detumescence. This study reveals oxygen levels are critical for smooth muscle responses to stimulation and drugs.
Area of Science:
- Physiology
- Urology
- Smooth Muscle Biology
Background:
- Penile erection and detumescence depend on corporal smooth muscle function under varying oxygen levels (pO2).
- Understanding the impact of low oxygen (anoxia) on smooth muscle is crucial for erectile function.
Purpose of the Study:
- To investigate the effects of anoxia on rabbit corpus cavernosal smooth muscle.
- To determine how oxygenation state influences responses to electrical field stimulation and various pharmacological agents.
Main Methods:
- Isolated strips of rabbit corpus cavernosal tissue were used.
- Tissue responses were measured under both oxygenated (normoxic) and anoxic conditions.
- Stimulation included electrical field stimulation and pharmacological agents like phenylephrine, bethanechol, ATP, and KCl.
Main Results:
- Anoxia abolished spontaneous contractions and reduced basal tension.
- Neither field stimulation nor agents like ATP or bethanechol could relax tissue below anoxic basal tension.
- Alpha-adrenergic agonists induced only weak, transient contractions under anoxia, eliminating tonic responses.
- Normoxic field stimulation caused graded relaxations, while anoxic stimulation resulted in contractions at all frequencies.
Conclusions:
- Corneal smooth muscle tone, activity, and responses to agonists and stimulation are oxygen-dependent.
- The failure of alpha-adrenergic stimulation to induce tonic contraction in anoxic conditions mirrors the ineffectiveness of such agents in treating ischemic priapism.