Neurotransmitters play an important role on function of lower urinary tract. In the present study, we have attempted to measure neurotransmitters (acetylcholine, norepinephrine, adenosine 5'-triphosphate, nitric oxide) releases induced by electrical field stimulation (EFS) in rabbit lower urinary tract smooth muscles using high performance liquid chromatography (HPLC) coupled with microdialysis procedure. The rabbit lower urinary tract smooth muscle strips were mounted in thermostatically controlled organ bath for isometric tension recordings. Microdialysis probe, which was perfused with Ringer solution, was inserted into the smooth muscle strip.The dialysate during EFS was collected, and the amount of neurotransmitter released in the dialysate was measured by HPLC. The effects of stimulation frequency on neurotransmitter release were evaluated. All neurotransmitter releases induced by EFS were increased in a frequency dependent manner. After pretreatment with tetrodotoxin, the neurotransmitter releases induced by EFS were significantly suppressed to the control levels. These results suggested that this new method was useful to investigate the neurotransmitter releases from lower urinary tract smooth muscles.
