Recruitment of unmyelinated C fibers mediates the bladder-inhibitory effects of tibial nerve stimulation in a continuous-fill anesthetized rat model.

Recruitment of unmyelinated C fibers mediates the bladder-inhibitory effects of tibial nerve stimulation in a continuous-fill anesthetized rat model. Am J Physiol Renal Physiol. 2019 May 29;: Authors: Paquette JP, Yoo PB Abstract Although percutaneous tibial nerve stimulation (PTNS) is considered a clinically-effective therapy for treating overactive bladder (OAB), the mechanism by which OAB symptoms are suppressed remains unclear. The goal of this study was to better understand the role of specific neural inputs (i.e., fiber types) on the bladder-inhibitory effects of tibial nerve stimulation (TNS). In 24 urethane-anesthetized rats, a continuous suprapubic saline infusion model was used to achieve repeated filling and emptying of the bladder. A total of 4 TNS trials (pulse frequency = 5 Hz) were applied in randomized order, where each trial used different amplitude settings: (1) no stimulation (control), (2) Aβ fiber activation, (3) Aδ fiber activation, and (4) C fiber activation. Each stimulation trial was 30 minutes in duration, with an inter-trial washout period of 60 to 90 minutes. Our findings showed that TNS evoked statistically significant changes in bladder function - e.g., bladder capacity, residual volume, voiding efficiency, and basal pressure - only at stimulation amplitudes that electrically recruited unmyelinated C fibers. In a subset of experiments, TNS also resulted in transient episodes of overflow incontinence. I...
Source: American Journal of Physiology. Renal Physiology - Category: Physiology Authors: Tags: Am J Physiol Renal Physiol Source Type: research