培养大鼠近端小管上皮细胞β - 2肾上腺素能功能。
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辛格H, Linas S
培养大鼠近端小管上皮细胞β - 2肾上腺素能功能。
中华医学杂志。1996年7月;271(1 Pt 2):F71-7。
- PubMed ID
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8760245 (PubMed视图］
- 摘要
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我们进行了研究，以确定功能性β 2肾上腺素受体是否存在于培养的大鼠近端小管上皮细胞中。为了确定培养的细胞在钠运输方面是否保持极性，细胞被酸负载。酸负载刺激了钠的转运。酸性细胞暴露于碱性细胞外pH进一步增强了钠的转运(在pH 7.50时22Na通量比pH 7.00高68.1 +/- 44%，P < 0.05)。培养的近端小管也表现出基底外侧86Rb吸收，其中65%为瓦巴因敏感。因此培养的细胞保持顶端Na/H反转运和基底外侧Na- k -腺苷三磷酸酶(Na- k - atp酶)。选择性β 2激动剂偏丙肾上腺素(10(-6)M)可使na - k - atp酶活性比对照组提高36 +/- 6% (P < 0.05)。刺激作用被ICI-118551阻断，这是一种选择性β 2拮抗剂。为了确定偏丙肾上腺素依赖性na - k - atp酶的增加是否依赖于根尖钠的进入，用二甲氯胺阻断根尖进入或用莫能菌素使其最大化。二甲酰亚胺和莫能菌素都能阻止偏丙肾上腺素激活na - k - atp酶。 Metaproterenol-mediated increases in Na-K-ATPase activity were associated with increases in sodium transport (27 +/- 10% above control, P < 0.05), which was prevented by dimethylamiloride. In contrast to isoproterenol, metaproterenol did not stimulate cAMP production. In summary, we have shown that functional beta 2-adrenoceptors are present on cultured rat proximal tubules. beta 2-Adrenoceptor activation results in increases in Na-K-ATPase and Na transport as a consequence of increased apical sodium entry.