Representative traces of the effects of cumulative intravenous doses of olanzapine on the cystometrograms (CMG) and external urethral sphincter EMG of anesthetized rats (n = 5). Top panel presents bladder pressure during CMG while bottom panel is integrated EMG recorded from the external urethral sphincter. Panels A and B also show the different parameters recorded from the CMG: BC = amount of fluid infused to elicit a contraction; PT = pressure at which contraction begins; PP = maximal pressure during contraction; CT= contraction time; ET = time between peak pressure and end of high frequency oscillations. The EMG activity was examined by dividing the bladder contraction into three phases in a modification of the technique of Chien et al.  a contraction phase (phase 1); an expulsion phase (phase 2) and a closing phase (phase 3). A) CMG following administration of control (saline). (B) Expanded time scale showing the expulsion phase and the high frequency oscillations (HFO) in the bladder record, with accompanying bursting in the EMG. C & D) 0.01 mg/kg of olanzapine does not have an effect on the CMG or the external urethral sphincter EMG. E & F) After 0.1 mg/kg of olanzapine, the amplitude of the HFO is diminished and the expulsion time is shortened. G & H) 1 mg/kg of olanzapine abolished HFO, there is no discernible expulsion time and the EMG record shows no bursting and a much lower level of activity compared to control. Calibration bar: A,C,E,G = 1 min; B,D,F,H = 1 sec.