Neuromodulation of bladder activity by stimulation of feline pudendal nerve using a transdermal amplitude modulated signal (TAMS)

Abstract

To develop a non-invasive neuromodulation method to regulate bladder activity. Neuromodulation of bladder activity was investigated in felines with an intact spinal cord under α-chloralose anesthesia using a transcutaneous stimulation method with surface electrodes attached to the skin area between the base of the tail and the sciatic notch. The bladder could be either inhibited or excited depending on stimulation frequency and bladder volume. With the bladder distended to induce large amplitude rhythmic isovolumetric bladder contractions, stimulation at a frequency between 5 and 7 Hz significantly suppressed the contractions. Stimulation applied during a cystometrogram (CMG) also increased bladder capacity by 44.3 ± 10.8%. At a frequency between 20 and 40 Hz the inhibitory effect on rhythmic bladder contractions was weak and did not increase bladder capacity during CMG. At low bladder volumes ranging between 60% and 100% of the bladder capacity 20 Hz stimulation-induced small amplitude (21.2 ± 14.6 cmH(2) O) bladder contractions. However, stimulation at 20 Hz induced large amplitude (111.7 ± 22.2 cmH(2) O) bladder contractions at a bladder volume about 100-110% of the bladder capacity after the rhythmic bladder contractions were completely inhibited by the inhibitory 5 Hz stimulation. Both inhibitory and excitatory effects on bladder activity can be obtained in cats using the non-invasive neural stimulation approach. This pre-clinical study warrants a further clinical trial to investigate the possibility of using this non-invasive stimulation method to treat incontinence or urinary retention.