Behavioral Monitoring and Neuromodulation of Feline Voiding Function

Neuromodulation is a standard treatment for bladder dysfunction. Although preclinical studies continue to develop new approaches, these experiments are often performed under anesthesia that can affect normal bladder system activity. The goal of this study was to evaluate the use of typical neuromodulation parameters in an awake, behaving large-animal model. During an aseptic surgery, catheters were inserted into the bladder of two male felines and a cuff electrode was placed around the left pudendal nerve. Catheters and electrode leads were housed in an enclosure mounted on the lower back. After recovery, test sessions in an open enclosure were performed approximately weekly. In each session, body-temperature saline was infused while the bladder pressure was monitored until the animal voided one or more times. During some bladder fills, electrical stimulation of the pudendal nerve was applied (5 or 33 Hz; 1.5 or 2 × motor threshold - MT) to determine whether stimulation parameters affected the interval between voiding events or the voiding efficiency. Animals tolerated supra-threshold stimulation as long as the current was slowly increased to a target level. Five-Hz stimulation increased the voiding interval over 33 Hz and no stimulation trials while 33 Hz stimulation at 2 MT led to a greater voiding efficiency. These results follow trends observed in non-behavioral studies, and support the use of this animal model in further translational bladder neuromodulation research.