鸭盐腺中的离子与能量代谢：呋塞米敏感的钠氯协同转运的可能作用。

Ions and energy metabolism in duck salt-gland: possible role of furosemide-sensitive co-transport of sodium and chloride.

作者信息

Ernst S A, van Rossum G D

出版信息

J Physiol. 1982 Apr;325:333-52. doi: 10.1113/jphysiol.1982.sp014153.

DOI:10.1113/jphysiol.1982.sp014153

PMID:7108780

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1251397/

Abstract

The effects of methacholine on net ionic movements and energy metabolism of the avian salt-gland have been studied, using slices of glands taken from salt-adapted Pekin ducks. The slices were equilibrated with media and drugs for 120 min at 1 degrees C before the experimental incubation at 38 degrees C.2. During incubation at 38 degrees C the slices accumulated K(+) and lost Na(+) and Cl(-). In the presence of methacholine, they retained more Na(+) and Cl(-) and accumulated less K(+), the maximal effects being given by 0.5-1.0 mM-methacholine. Similar results were obtained whether the medium contained 10 mM-Tris (used in most experiments) or 25 mM-HCO(3) (-) as the major buffer.3. The higher final levels of cell Na(+) and Cl(-) induced by methacholine were not seen when furosemide (1 mM) was also present. Methacholine did not induce a higher level of cell Na(+) when medium Cl(-) was replaced by I(-), NO(3) (-) or SO(4) (2-), and did not induce a higher Cl(-) content when medium Na(+) was replaced by choline or Li(+). The fall of K(+) accumulation caused by methacholine was also prevented by furosemide or by replacing Cl(-) in the medium with other anions. The anion-transport inhibitors, SCN(-) (up to 10 mM) and 4,4'-diisothiocyano-2,2'-disulphonic acid stilbene (DIDS) (up to 2 mM) did not prevent the effects of methacholine.4. Methacholine stimulated respiration and lowered the slice ATP contents, and these effects were both prevented by ouabain or furosemide. Ouabain, but not furosemide, also reduced the basal (i.e. in the absence of methacholine) rate of respiration and raised the ATP level. SCN(-) and DIDS had no effect on basal or stimulated respiration or on ATP contents.5. The respiratory stimulation and fall of ATP induced by methacholine were totally prevented if medium Na(+) was replaced by choline. Replacement of Na(+) by Li(+) caused some stimulation of basal respiration; it also permitted some loss of ATP in the presence of methacholine, but the loss was smaller than that seen in the normal Na(+) medium.6. The respiratory stimulation and fall of ATP induced by methacholine were prevented if medium Cl(-) was replaced by SO(4) (2-). The effects of methacholine were partially blocked when NO(3) (-) replaced Cl(-).7. The results are consistent with the stimulation by methacholine of a furosemide-sensitive, coupled entry of Na(+) and Cl(-) into the cells, associated with a loss of K(+). This would result in a stimulation of Na(+) extrusion by the ouabain-sensitive transport system for Na(+) and K(+) with increased consumption of ATP.

摘要

利用取自经盐分适应的北京鸭的盐腺切片，研究了乙酰甲胆碱对禽类盐腺净离子转运和能量代谢的影响。在38℃进行实验孵育前，将切片在1℃下用培养基和药物平衡120分钟。
在38℃孵育期间，切片积累K⁺，并丢失Na⁺和Cl⁻。在乙酰甲胆碱存在的情况下，它们保留了更多的Na⁺和Cl⁻，积累的K⁺更少，0.5 - 1.0 mM的乙酰甲胆碱产生最大效应。无论培养基中含有10 mM - Tris（大多数实验中使用）还是25 mM - HCO₃⁻作为主要缓冲剂，都得到了类似的结果。
当同时存在呋塞米（1 mM）时，未观察到乙酰甲胆碱诱导的细胞Na⁺和Cl⁻的较高终末水平。当培养基中的Cl⁻被I⁻、NO₃⁻或SO₄²⁻取代时，乙酰甲胆碱未诱导细胞Na⁺水平升高，当培养基中的Na⁺被胆碱或Li⁺取代时，也未诱导Cl⁻含量升高。呋塞米或用其他阴离子取代培养基中的Cl⁻也可防止乙酰甲胆碱引起的K⁺积累下降。阴离子转运抑制剂SCN⁻（高达10 mM）和4,4'-二异硫氰酸 - 2,2'-二磺酸芪（DIDS）（高达2 mM）不能阻止乙酰甲胆碱的作用。
乙酰甲胆碱刺激呼吸并降低切片ATP含量，哇巴因或呋塞米均可阻止这些作用。哇巴因而非呋塞米还降低了基础（即无乙酰甲胆碱时）呼吸速率并提高了ATP水平。SCN⁻和DIDS对基础或刺激的呼吸或ATP含量无影响。
如果用胆碱取代培养基中的Na⁺，则可完全阻止乙酰甲胆碱诱导的呼吸刺激和ATP下降。用Li⁺取代Na⁺会引起基础呼吸的一些刺激；在乙酰甲胆碱存在的情况下，它也允许一些ATP的损失，但损失小于在正常Na⁺培养基中所见。
如果用SO₄²⁻取代培养基中的Cl⁻，则可阻止乙酰甲胆碱诱导的呼吸刺激和ATP下降。当NO₃⁻取代Cl⁻时，乙酰甲胆碱的作用被部分阻断。
结果与乙酰甲胆碱刺激呋塞米敏感的、Na⁺和Cl⁻耦联进入细胞的过程一致，这与K⁺的丢失相关。这将导致通过对哇巴因敏感的Na⁺和K⁺转运系统刺激Na⁺的排出，同时ATP消耗增加。