Effects of intrathecal administration of pituitary adenylate cyclase activating polypeptide on lower urinary tract functions in rats with intact or transected spinal cords

Exp Neurol, 2008 · DOI: · Published: June 1, 2008

Simple Explanation

This study investigates how a substance called PACAP-38 affects bladder function in rats with and without spinal cord injuries. PACAP-38 is a brain-gut peptide. The experiments looked at bladder contractions and the activity of the external urethral sphincter (EUS), which controls urine flow. The study also examined the role of sympathetic nerves in these responses. The findings suggest that PACAP-38 can influence the parasympathetic nerves controlling the bladder after spinal cord injury, and that removing sympathetic nerve pathways enhances this effect. PACAP-38 activates spinal circuitry.

Study Duration

Not specified

Participants

43 female Sprague-Dawley rats

Evidence Level

Not specified

Key Findings

1
In spinal cord transected (SCT) rats, PACAP-38 increased bladder contraction amplitude under isovolumetric conditions, and this effect was enhanced by sectioning the hypogastric nerves (HGNs).
2
During continuous cystometrograms (CMGs) in SCT rats, PACAP-38 reduced bladder contraction amplitude and external urethral sphincter (EUS) EMG activity.
3
In spinal cord intact rats, PACAP-38 increased bladder contraction amplitude during CMGs, and this effect was also enhanced by HGN section.

Research Summary

The study investigates the effects of intrathecal PACAP-38 on lower urinary tract function in rats with intact or transected spinal cords (SCT). PACAP-38's effects varied depending on experimental conditions, with increased bladder contraction amplitude under isovolumetric conditions and decreased amplitude during continuous CMGs in SCT rats. The findings suggest that PACAP-38 modulates parasympathetic outflow to the bladder and affects EUS activity, potentially acting as a neurotransmitter in micturition reflex pathways.

Practical Implications

Potential therapeutic target

PACAP-38 and its receptors may be potential therapeutic targets for managing bladder dysfunction, particularly after spinal cord injury.

Understanding micturition

The study enhances understanding of the complex neural control of micturition and the role of PACAP in these pathways.

Spinal cord injury treatments

The research suggests potential strategies for improving bladder function in individuals with spinal cord injuries, such as modulating PACAP signaling.

Study Limitations

1
The study was conducted in decerebrate, unanesthetized rats, which may not fully reflect the effects in conscious animals.
2
The use of a transurethral catheter could potentially affect urodynamic measurements.
3
Variability of bladder activity made it difficult to obtain consistent recordings over a long period of time.

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