Distribution of Convergent Afferents Innervating Bladder and Prostate at Dorsal Root Ganglia in Rats

Objectives

To investigate the distribution of dichotomizing afferents supplying both the prostate and urinary bladder, and to discern the effects of noxious stimulation of the prostate on urinary bladder function in rats.

Methods

Dual retrograde fluorescence labeling was used to investigate the neurogenic aspect of urinary bladder function. The dual distribution of dorsal root ganglia (DRG) cells was determined by propidium iodide (PI) and propidium bisbenzimide (Bb) staining into the prostate and bladder. To examine mechanical sensitivity of the bladder, conscious filling cystometry was performed before and after completion of Freund adjuvant injection into the prostate.

Results

Double-labeled positive cells were found in the lumbosacral DRG, predominantly in L1-L2 and L6-S1, with distribution varyinig from 7.5% to 14%. Most of the double-labeled cells were classified as small and medium in size. Prostatic irritation had no effect on the number of labeled cells. With the use of cystometry, prostatic irritation was found to shorten mean micturition interval (P <.05), decrease mean volume threshold inducing micturition, and increase baseline pressure and threshold pressure (P <.05), but to lower peak micturition pressure compared with that in controls (P <.01).

Conclusions

These findings suggest that bladder–prostate convergent DRG neurons may play a role in bladder–prostate cross-sensitization after prostatitis. This study also provided neuronal anatomical evidence for voiding dysfunction associated with chronic prostatitis/chronic pelvic pain syndrome.