Phosphodiesterase type 2 distribution in the guinea pig urinary bladder

Area of Science:

• Urology
• Pharmacology
• Cell Biology

Background:

• Nitric oxide-stimulated cyclic guanosine monophosphate (cGMP) synthesis is vital for urinary bladder function.
• Phosphodiesterase 1 (PDE1) and PDE5 inhibitors are used for bladder storage and voiding disorders.
• The distribution of phosphodiesterase type 2 (PDE2) in the bladder remains uncharacterized.

Purpose of the Study:

• To determine the distribution and site of action of PDE2 within the guinea pig urinary bladder wall.

Main Methods:

• Guinea pig bladders were treated with a specific PDE2 inhibitor (Bay 60-7550) and stimulated with diethylamine-NONOate.
• Tissues were cryosectioned and examined for cGMP immune-reactivity.
• Co-staining was performed for vimentin, synaptic vesicle protein 2, calcitonin gene-related protein, and protein gene product 9.5.

Main Results:

• PDE2 inhibition by Bay 60-7550 most effectively reduced cGMP breakdown in the urothelial and suburothelial layers, and on nerve fibers.
• Following PDE2 inhibition, cGMP was primarily found in intermuscle interstitial cells and nerve fibers of the outer muscle layers.
• This indicates significant PDE2 activity in these bladder regions.

Conclusions:

• This study is the first to map PDE2 distribution in the bladder.
• PDE2 is present in the urothelium (primarily umbrella cells), suburothelial interstitial cells, outer muscle layers, and nerve fibers.
• These findings provide a basis for investigating PDE2's role in bladder physiology and pathology.