Effect of protamine on ion conductance of ascending thin limb of Henle's loop from hamsters.
Effect of protamine on ion conductance of ascending thin limb of Henle's loop from hamsters.
复制标题
鱼精蛋白对仓鼠亨利氏袢升细肢离子电导的影响。
DOI：
10.1152/ajprenal.1991.261.4.f593
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
M. Imai
中科院分区：
文献类型：
--
作者：
S. Koyama;K. Yoshitomi;M. Imai
为了评价细胞旁分流通路在仓鼠升支细肢（ATL）中的作用，我们研究了细胞旁传导选择性阻断剂鱼精蛋白对体外微灌注过程中盐扩散电压（DVT）和跨壁电阻（RT）的影响。当向管腔中加入300 μ g/ml鱼精蛋白时，管腔NaCl浓度降低时产生的管腔阴性dVT从-7.3 +/-0.5 mV进一步增加至-10.3 +/- 0.7 mV，计算的Na+/Cl-渗透率从0.46 +/- 0.03降低至0.31 +/- 0.03。虽然鱼精蛋白的作用在从管腔中移除试剂后持续存在，但添加30 U/ml肝素使DVT恢复至对照水平。鱼精蛋白的作用在30至300微克/毫升范围内呈剂量依赖性。鱼精蛋白也从浴中发挥其作用，并且该作用被来自管腔或浴中的肝素抑制。当施加NaCl梯度的方向相反时，抑制效果几乎相同。在浴中用0.1 mM 5-硝基-2-（3-苯基丙基氨基）-苯甲酸酯（NPPB）抑制跨细胞Cl-转运引起管腔阳性DVT。鱼精蛋白可显著降低该电压。鱼精蛋白显著降低Na+的表观迁移数，但稍增加Cl-的值。神经电缆分析显示，向管腔中加入300微克/ml鱼精蛋白使RT从0.59 +/- 0.10增加到1.20 +/- 0.20 Ω. cm 2，30 U/ml肝素可逆转该效应。（250字处删节）
To evaluate the contribution of paracellular shunt pathway in ascending thin limb (ATL) of hamsters, we examined the effect of protamine, a selective blocker of paracellular conductance, on salt-diffusion voltage (dVT) and transmural resistance (RT) during in vitro microperfusion. Lumen-negative dVT generated on reduction of lumen NaCl concentration was increased further from -7.3 +/- 0.5 to -10.3 +/- 0.7 mV when 300 micrograms/ml protamine was added to the lumen, and calculated Na+/Cl- permeability ratio was decreased from 0.46 +/- 0.03 to 0.31 +/- 0.03. Although the effect of protamine persisted after removal of the agent from the lumen, addition of 30 U/ml heparin returned the dVT toward the control level. The effect of protamine was dose dependent from 30 to 300 micrograms/ml. Protamine also exerted its effect from the bath, and the effect was inhibited by heparin either from the lumen or from the bath. The inhibitory effect was almost the same when the orientation of imposed NaCl gradient was reversed. Inhibition of transcellular Cl- transport with 0.1 mM 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) in the bath caused lumen-positive dVT. This voltage was decreased significantly by protamine. Protamine markedly decreased the apparent transference number for Na+ but slightly increased the value for Cl-. Transmural cable analysis showed that 300 micrograms/ml protamine added to the lumen increased RT from 0.59 +/- 0.10 to 1.20 +/- 0.20 omega.cm2, with the effect being reversed by 30 U/ml heparin.(ABSTRACT TRUNCATED AT 250 WORDS)