Almeida A J, Burg M B
Am J Physiol. 1982 Oct;243(4):F330-4. doi: 10.1152/ajprenal.1982.243.4.F330.
Connecting tubules were dissected from rabbit kidneys and perfused in vitro with a solution identical to that in the bath. Transepithelial sodium fluxes were measured with 22Na. The mean lumen-to-bath flux was 33.7 +/- 3.4 peq . cm-1 . s-1 and the mean bath-to-lumen flux was 13.4 +/- 3.4 peq . cm-1 . s-1. Thus, the net sodium transport was 20.3 peq . cm-1 . s-1, which is approximately 3--4 times higher than the one previously measured in cortical collecting ducts under similar conditions. The sodium permeability calculated from the bath-to-lumen measurements corrected for mean voltage was 1.22 x 10(-5) cm .s-1. The mean transepithelial electrical resistance was 31 omega . cm2. This sodium permeability is much higher and the electrical resistance much lower than those in cortical collecting ducts. Spontaneous transepithelial voltage was oriented negative in the lumen and ranged up to -42 mV at low perfusion pressures. When the perfusion pressure was increased, the voltage decreased to approximately -5 mV without any measurable change in the electrical resistance or the lumen-to-bath sodium flux.
从兔肾中分离出连接小管，并在体外用与浴液相同的溶液进行灌注。用22Na测量跨上皮钠通量。平均管腔到浴液的通量为33.7±3.4皮摩尔·厘米-1·秒-1，平均浴液到管腔的通量为13.4±3.4皮摩尔·厘米-1·秒-1。因此，钠的净转运量为20.3皮摩尔·厘米-1·秒-1，这比之前在类似条件下皮质集合管中测得的值高约3至4倍。根据浴液到管腔的测量值并校正平均电压后计算出的钠通透性为1.22×10(-5)厘米·秒-1。平均跨上皮电阻为31欧姆·厘米2。这种钠通透性比皮质集合管中的高得多，电阻则低得多。自发跨上皮电压在管腔内呈负向，在低灌注压力下可达-42毫伏。当灌注压力增加时，电压降至约-5毫伏，而电阻或管腔到浴液的钠通量没有任何可测量的变化。
