兔肾离体灌注皮质集合管中的肾小管周pH值和跨管电位

Peritubular pH and transtubular potentials in isolated perfused cortical collecting ducts of rabbit kidney.

Douglas R J, Isaacson L C

J Physiol. 1972 Mar;221(3):645-55. doi: 10.1113/jphysiol.1972.sp009773.

Abstract

Cortical collecting ducts were dissected from slices of rabbit kidney, then perfused in vitro.2. Transtubular electrical potentials were measured before and after abrupt changes in peritubular fluid pH.3. Variation in peritubular fluid pH, induced either by alteration in HCO(3) (-) concentration or in H(2)PO(4) (-)/HPO(4) (2-) ratio, produced biphasic responses in potential. Thus, reduction in pH caused an immediate fall, and then a prolonged and marked rise, in transtubular potential. The converse occurred on raising the pH.4. Variation in luminal fluid pH between pH 4.85 and pH 7.35 did not alter this pattern of response.5. In contrast to the above, reduction of peritubular fluid pH by elevation of P(CO2) produced either no effect or a decrease in transtubular potential.6. The transtubular potential of the cortical collecting duct appears to be a function of the pH gradient across some as yet unidentified part of the wall of the duct.

摘要

从兔肾切片中分离出皮质集合管，然后进行体外灌注。
在肾小管周围液体pH值突然变化之前和之后测量跨管电位。
由HCO(3) (-)浓度改变或H(2)PO(4) (-)/HPO(4) (2-)比值改变引起的肾小管周围液体pH值变化，会产生双相电位反应。因此，pH值降低会导致跨管电位立即下降，然后出现持续且显著的上升。pH值升高时则会出现相反的情况。
管腔内液体pH值在4.85至7.35之间变化不会改变这种反应模式。
与上述情况相反，通过升高P(CO2)降低肾小管周围液体pH值，要么没有影响，要么会使跨管电位降低。
皮质集合管的跨管电位似乎是跨导管壁某个尚未明确的部分的pH梯度的函数。