Can intraurethral stimulation inhibit micturition reflex in normal female rats?

OBJECTIVE The study was designed to determine the effect of low frequency (2.5Hz) intraurethral electrical stimulation on bladder capacity and maximum voiding pressures. MATERIALS AND METHODS The experiments were conducted in 15 virgin female Sprague-Dawley rats (220-250g). The animals were anesthetized by intraperitoneal injection of urethane (1.5g/kg). Animal care and experimental procedures were reviewed and approved by the Institutional Animal Care and Use Committee of Antwerp University (code: 2013-50). Unipolar square pulses of 0.06mA were used to stimulate urethra at frequency of 2.5Hz (0.2ms pulse width) in order to evaluate the ability of intraurethral stimulation to inhibit bladder contractions. Continuous stimulation and intermitente stimulation with 5sec ''on'' and 5sec ''off'' duty cycle were applied during repeated saline cystometrograms (CMGs). Maximum voiding pressures (MVP) and bladder capacity were investigated to determine the inhibitory effect on bladder contraction induced by intraurethral stimulation. RESULTS The continuous stimulation and intermittent stimulation significantly (p<0.05) decreased MVP and increased bladder capacity. There was no significant difference in MVP and bladder capacity between continuous and intermittent stimulation group. CONCLUSIONS The present results suggest that 2.5Hz continuous and intermittent intraurethral stimulation can inhibit micturition reflex, decrease MVP and increase bladder capacity. There was no significant difference in MVP and bladder capacity between continuous and intermittent stimulation group.