[Effects of tetramethylpyrazine on cytosolic free calcium concentration in penis corpus cavernsum smooth muscle cells in rabbits].

ABSTRACT

OBJECTIVE: To study the effects of Chinese medicine tetramethylpyrazine (TMP) on intracellular free calcium ([Ca2+]i) in cultured penis corpus cavernosum smooth muscle cell (PCSMC) in rabbits. METHODS: By using laser scanning confocal microscope (LSCM), the [Ca2+]i fluorescence signal changes was investigated in cultured PCSMC loaded with Ca2+ indicator Fluo-3/AM and divided into potassium chloride(KCl) group and norepinephrine (NE) group. Compared with verapamil (Ver), the effects of TMP was observed in different concentrations on [Ca2+]i increase induced by high potassium and NE. RESULTS: TMP had no obvious effect on resting PCSMC [Ca2+]i. It was found that 1, 10, 100 mumol/L TMP significantly inhibited [Ca2+]i increase induced by high potassium-depolarization. The peak inhibition rates were (38.6 +/- 3.0)%, (44.1 +/- 2.4)% and (53.7 +/- 4.1)% respectively. TMP could also inhibit cytosolic calcium pool release induced by 1 mumol/L NE. The peak inhibition rates were (13.9 +/- 2.7)%, (21.2 +/- 1.9)% and (29.5 +/- 3.6)% respectively. CONCLUSIONS: TMP can inhibit rabbit PCSMC [Ca2+]i significantly by suppressing voltage-dependent calcium channel and cytosolic calcium pool release. The effect, similar to Ver, signifies the important mechanism of erectile dysfunction (ED) therapy.