Tang Zhi-guo, Liang Chao-zhao, Shen Bing, Hao Zong-yao, Zhou Zheng-xing
Department of Urology, First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.
Zhonghua Yi Xue Za Zhi. 2007 Mar 27;87(12):842-6.
To investigate the potassium channel currents and response thereof to the blocker of potassium channel in epithelium of prostate of Sprague Dawley (SD) rats.
The dorsolateral lobes of prostates of 20 3-month-old (adult) male SD rats and 20 12-month-old (elderly) SD rats were removed, cut into small pieces of the size of 1 approximately 2 mm(3) in phosphate-buffered Ca(2+)-free Ringer's solution, and digested by collagenase IV for 25 min. Then the tissue chunks were put into fresh solution and gently agitated. These cells were cultured for one week. Pan-keratin immunocytochemistry was conducted. The potassium channel current of the prostate epithelium was recorded by whole-cell voltage clamp. Tetraethylammonium (TEA), a blocker of calcium-activated potassium channel of the concentration of 1 mmol/L, and 1 mol/L + 1 mmol/L 4-aminopyridine (4-AP), blocker of voltage-dependent potassium channel inhibitor, were sequentially added into the extra-cellular fluid and the current density was recorded.
TEA specifically inhibited the K(Ca) current After the addition of TEA and TEA + 4-AP, the current density at the potential of +80 mv of the 12-month-old rats was (18.48 +/- 1.7) pA/pF, significantly higher than that of the 3-month-old rats [(10.84 +/- 1.54) pA/pF, P < 0.01]. The original peak current of the 3-month-old rats was (9.5 +/- 1.8) pA/pF and became (5.4 +/- 3.1) pA/pF after the addition of TEA, decreased by 44% (P < 0.01); and the peak current of the 12-month-old rats was (19.1 +/- 2.9) pA/pF and became (7.2 +/- 3.2) pA/pF after the addition of TEA, decreased by 63% (P < 0.01).
Elderly rats have stronger potassium channel currents than adult rats, and their K(Ca) current is more sensitively to TEA. Aging is related to decreased prostate gland cell secretion.
研究Sprague Dawley（SD）大鼠前列腺上皮细胞的钾通道电流及其对钾通道阻滞剂的反应。
取20只3月龄（成年）雄性SD大鼠和20只12月龄（老年）SD大鼠的前列腺背外侧叶，在无钙磷酸盐缓冲林格氏液中切成约1至2立方毫米的小块，用IV型胶原酶消化25分钟。然后将组织块放入新鲜溶液中轻轻搅拌。这些细胞培养一周。进行全角蛋白免疫细胞化学检测。采用全细胞膜片钳记录前列腺上皮细胞的钾通道电流。将浓度为1 mmol/L的钙激活钾通道阻滞剂四乙铵（TEA）和电压依赖性钾通道抑制剂1 mol/L + 1 mmol/L 4-氨基吡啶（4-AP）依次加入细胞外液，并记录电流密度。
TEA特异性抑制K（Ca）电流。加入TEA和TEA + 4-AP后，12月龄大鼠在+80 mV电位下的电流密度为（18.48±1.7）pA/pF，显著高于3月龄大鼠[（10.84±1.54）pA/pF，P < 0.01]。3月龄大鼠的原始峰值电流为（9.5±1.8）pA/pF，加入TEA后变为（5.4±3.1）pA/pF，下降了44%（P < 0.01）；12月龄大鼠的峰值电流为（19.1±2.9）pA/pF，加入TEA后变为（7.2±3.2）pA/pF，下降了63%（P < 0.01）。
老年大鼠的钾通道电流比成年大鼠更强，其K（Ca）电流对TEA更敏感。衰老与前列腺细胞分泌减少有关。
