Correlation between pharmacologically-induced changes in cystometric parameters and spinal c-Fos expression in rats

Area of Science:

• Pharmacology
• Neuroscience
• Urology

Background:

• Inhibiting bladder sensory transmission is key for treating urine storage symptoms.
• Bladder hyperactivity often involves increased afferent activity.
• Understanding drug effects on bladder afferent pathways is crucial for pharmacotherapy.

Purpose of the Study:

• To investigate the relationship between drug-induced cystometric changes and spinal c-Fos expression.
• To assess the efficacy of oxybutynin, tamsulosin, CL316243, and morphine in a rat model of bladder hyperactivity.
• To correlate bladder afferent activity markers with functional bladder parameters.

Main Methods:

• Rats with acetic acid-induced bladder hyperactivity received intravenous infusions of oxybutynin, tamsulosin, CL316243, or saline.
• Cystometric parameters (intermicturition interval, micturition pressure, pressure threshold) were measured.
• Spinal c-Fos expression in the L6 dorsal spinal cord was quantified via immunostaining.

Main Results:

• CL316243 and morphine increased intermicturition intervals; oxybutynin and tamsulosin did not.
• Oxybutynin and CL316243 decreased micturition pressure; tamsulosin and morphine did not.
• CL316243 decreased pressure threshold, while morphine increased it.
• All tested drugs significantly reduced spinal c-Fos expression (MOR>CL>OXY>TAM).
• Reduced c-Fos expression correlated negatively with intermicturition interval and pressure threshold.

Conclusions:

• Clinically relevant drugs effectively suppress bladder afferent activity, evidenced by decreased spinal c-Fos expression.
• The degree of afferent pathway suppression varies among different pharmacological mechanisms.
• Spinal c-Fos expression serves as a reliable marker for bladder afferent activity, correlating with key functional parameters.