Figure 1.

Analysis of bladder variables recorded from an urethane-anaesthetized female rat: traces showing the effects evoked by infusing (0.5 ml min⁻¹) saline (stippled horizontal bar) into the bladder on bladder and urethra pressure (mmHg) and on raw and integrated external urethral sphincter (EUS-EMG) activity and how these changes were measured. Once three similar bladder contractions (phasic increases in bladder pressure) were observed, the saline infusion was switched off and measurements were made on the height and duration of each of these contractions (^*), that is, those falling between the two dashed lines as well as the associated urethral relaxations and integrated EUS-EMG. These values were then averaged to give the control reflex-evoked changes (see Table 1). In addition, the thresholds, pressure and volume to evoke this reflex were also calculated. The measurements were made from the beginning of the saline infusion to the beginning of a bladder contraction associated with urethral relaxation.