Bladder inhibition by intermittent pudendal nerve stimulation in cat using transdermal amplitude-modulated signal (TAMS).

ABSTRACT

AIMS: To determine if intermittent stimulation of the pudendal nerve using a transcutaneous stimulation method can inhibit reflex bladder activity. Intermittent stimulation consumes less electrical power than continuous stimulation, requiring a smaller battery and reducing the size of the stimulator for neuromodulation therapy. METHODS: A non-invasive stimulation method employing a transdermal amplitude-modulated signal (TAMS) was used in 18 α-chloralose anesthetized cats to stimulate the pudendal nerve via electrodes attached to the skin surface. Intermittent stimulation of different duty cycles was applied during repeated cystometrograms (CMGs) to inhibit reflex bladder activity. The bladder capacity measured during each CMG was used to indicate the inhibitory effect induced by the stimulation. RESULTS: Continuous stimulation maximally increased bladder capacity to 172.6 ± 15% of the control capacity, while intermittent stimulation at the duty cycles of 30/30, 5/5, and 1/1 ("on/off" in seconds) significantly (P < 0.05) increased bladder capacity to 132 ± 7.5%, 154.2 ± 20%, and 165.5 ± 28%, respectively. The inhibitory effect was gradually reduced as the "on/off" ratio was decreased. CONCLUSIONS: This pre-clinical study indicated that intermittent stimulation of the pudendal nerve could be as effective as continuous stimulation to inhibit reflex bladder activity. These results are useful for the design and development of new stimulator technology to treat overactive bladder, and are also important for understanding pudendal neuromodulation therapy.