Neural mechanisms of impaired micturition reflex in rats with acute partial bladder outlet obstruction

• Published in: Neuroscience 2000, Vol.96 (1), p.221-230
• Main Authors: Chien, C.T., Yu, H.J., Lin, T.B., Chen, C.F.
• Format: Article
• Language: English
• Subjects: Acute Disease; Adenosine Diphosphate - analogs & derivatives; Adenosine Diphosphate - pharmacology; Animals; Atropine - pharmacology; Biological and medical sciences; bladder outlet obstruction; cholinergic; Drug Combinations; Electromyography; Female; Fundamental and applied biological sciences. Psychology; high-frequency oscillation; micturition; Muscarinic Antagonists - pharmacology; Nervous System - physiopathology; Neurons, Afferent - physiology; Neurons, Efferent - physiology; Nicotinic Antagonists - pharmacology; pelvic nerve; Pelvis - innervation; purinergic; Rats; Rats, Wistar; Reflex; Tubocurarine - pharmacology; Urethra - physiopathology; Urinary Bladder - drug effects; Urinary Bladder - physiopathology; Urinary Bladder Neck Obstruction - physiopathology; Urination; Vertebrates: urinary system
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(99)00508-4

To determine the contribution of neural elements to micturition, we evaluated, in intact rats, the cystometrogram, pelvic afferent nervous activity, pelvic efferent nervous activity and external urethral sphincter-electromyogram activity in the normal and acute partial bladder outlet obstruction states. In the normal state, in response to saline filling, mechanoreceptor-dependent pelvic afferent nervous activity gradually activated and finally triggered a voiding reflex, including four phases of detrusor contractions. Phase 1 was characterized by an initial rising intravesical pressure, Phase 2 was characterized by a series of high-frequency oscillations in intravesical pressure, Phase 3 contraction was characterized by a rebound intravesical pressure and Phase 4 contraction was characterized by a rapid fall in intravesical pressure. In the acute partial bladder outlet obstruction state, Phase 1 contraction rose and high-frequency oscillations fell in Phase 2. This voiding dysfunction is ascribed to the bursting extraurethral sphincter activity being converted to tonic extraurethral sphincter activity. In summary, the suppressed high-frequency oscillations in Phase 2 of the detrusor muscle contraction could be detrimental to efficient voidings in the acute partial bladder outlet obstructed rat.