In vivo cystometrogram studies in urethane-anesthetized and conscious guinea pigs

Area of Science:

• Pharmacology
• Urology
• Physiology

Background:

• Urinary bladder function assessment often relies on cystometry.
• Anesthesia can potentially influence physiological measurements during cystometry.
• Understanding anesthesia's impact is crucial for reliable in vivo studies.

Purpose of the Study:

• To compare in vivo cystometry in urethane-anesthetized vs. awake guinea pigs.
• To evaluate the effect of anesthesia on cystometrogram (CMG) parameters.
• To assess the impact of anesthesia on anticholinergic drug effects during CMG.

Main Methods:

• In vivo cystometry was performed in urethane-anesthetized and awake guinea pigs.
• Surgically implanted catheters were used in awake animals.
• Anticholinergic drugs, including dexetimide and oxybutynin, were administered.

Main Results:

• Anticholinergic drugs dose-dependently inhibited peak intravesical pressure (PvesP) by ~80%.
• No significant effects on threshold pressure or bladder capacity were observed.
• Oxybutynin showed similar potency and duration of action in both preparations; stereoselectivity was noted with dexetimide.

Conclusions:

• Urethane anesthesia does not significantly alter CMG parameters or oxybutynin's effects.
• The urethane-anesthetized guinea pig is a valid model for studying bladder filling and voiding.
• This preparation facilitates in vivo evaluation of cystometry and drug efficacy.