Objective        To investigate the function of intracellular store operated calcium cha

nnels (SOCCs) in the contraction of bladder smooth muscle of rats.       Methods        Bladder smooth muscle cells (BSMCs) and bladder smooth muscle strips were isolated from female SD rats. RT-PCR was employed to detect the expression of the SOCCs related genes in the bladder tissues. The SOCCs agonist CPA (10 μmol/L) and its inhibitor SKF-96365 (10 μmol/L) was used to treat the isolated BSMCs and muscle stripes. The isolated bladder smooth muscle was used for contraction

in vitro

. The cell current was recorded with whole-cell patch-clamp technique. The changes of intracellular calcium ion were observed by lacer scanning confocal microscopy.       Results       TRPC3

TRPC4 and STIM1 were expressed in BSMCs. CPA treatment resulted in significant increase in the contraction frequency (5.937 5±1.108 0 times/min) and obvious decrease in the amplitude (0.067 1±0.027 0 g) of the isolated muscle strips (

P

<

0.05). Whole-cell patch-clamp technique indicated that CPA treatment induced obvious increase in the cell calcium currents

with the current destiny of -3.127 1±0.908 7 pA/pF at -80 mV and 1.048 1±0.322 5 pA/pF at 20 mV (

P

<

0.05). The relative intensity of fluorescence was significant enhanced (1.150 7±0.212 1) than the cells without treatment (

P

<

0.05). On the contrary

the use of SKF-96365 decreased the contraction frequency to 5.081 3±1.129 5 times/min and increased amplitude  to 0.079 0±0.033 0 g of the bladder smooth muscle strips

both with significant difference with the addition of CPA (

P

<

0.05). The calcium currents became little compared with that induced by CPA treatment

and the current destiny was -2.678 1±0.804 4 pA/pF at -80 mV  and 0.907 7±0.346 2 pA/pF at 20 mV (

P

<

0.05). The relative intensity of fluorescence was also significantly reduced (1.028 9±0.204 7) compared with the treatment of CPA (

P

<

0.05).       Conclusion       The bladder smooth muscle expresses SOCCs

and its contraction is affected by the channels.