Figure 1

Experimental setup, electrode design/placement, and data analysis. (A) Experimental setup showing the rat on a raised platform to accommodate the balance for measuring void volume. The infusion pump (set at 0.25 ml/min) infuses saline into the bladder via a catheter in the bladder dome. (B) A modified Medtronic 5–6–5 array is shown alongside a customized Micro-Leads array. The diagram (right side) depicts the custom array (scale is mm). (C) Spinal level of electrode placement is determined after perfusion by markings (suture knots in overlaying muscle) and root level (shown and labeled in left image). Note: spinal levels are operationally defined as rostral (portion about the dorsal root entry zone) and caudal (below dorsal root entry zone). (D) Schematic representation of Medtronic electrode placement in all animals. R rostral, C caudal. Quantification of data was accomplished with a customized program. This program takes the cystometrogram (CMG) bladder pressure traces (bottom trace, E, labelled CMG channel) and places start and end markers for each void contraction (F, indicated by circles). Maximum contractile pressure, area under the curve, contractile time, and inter-contractile interval can then be recorded (F). The electromyography (EMG) channel from the external urethral sphincter (EUS; top trace, E) is analyzed by first comparing the amplitude to an initial baseline period. When the amplitude is twice the baseline amplitude it is considered the beginning of activity, whereas when activity returns back below this threshold it is the end of activity. During this activity period there are three divisions: rising tonic (from onset to bursting period), bursting time (G, bursts of activity with quiescent periods in between), and decaying tonic (from end of bursting to end of activity). Once characterized, the amount of time in each phase, amplitude, bursting frequency, pulse width, and inter-burst interval can be recorded.