Adrenergic receptors, Na+/H+ exchange and volume regulation in lungfish erythrocytes

被引：0

作者：

Koldkjær P. ^{[1
]}

Taylor E.W. ^{[2
]}

Glass M.L. ^{[3
]}

Wang T. ^{[4
]}

Brahm J. ^{[5
]}

McKenzie D.J. ^{[2
]}

Jensen F.B. ^{[6
]}

机构：

[1] School of Biological Science, University of Liverpool, Derby Building, Liverpool L69 3GS, Brownlow Street

[2] School of Biosciences, University of Birmingham

[3] Department of Physiology, Medical Faculty, University of Sao Paulo, Riberao Preto

[4] Institute of Biology, Aarhus University

[5] Department of Medical Physiology, Panum Institute, Copenhagen University

[6] Institute of Biology, University of Southern Denmark

来源：

Journal of Comparative Physiology B | 2002年 / 172卷 / 1期

关键词：

Adrenergic receptors; Erythrocytes; Lungfish; Volume regulation Na[!sup]+[!/sup]/H[!sup]+[!/sup] excnage;

D O I：

10.1007/s00360-001-0232-1

中图分类号：

学科分类号：

摘要：

Aestivation in African and South American lungfish (Protopterus and Lepidosiren, respectively) is associated with elevations of extracellular osmolarity. Osmotic shrinkage of Protopterus red blood cells (RBCs) caused a small but significant stimulation of the Na influx that was amiloride-sensitive, suggesting involvement of the Na+/H+ exchanger (NHE). The associated in vitro regulatory volume increase was insignificant within a time frame of 120 rain, but the shrinkage-activated Na+ influx may be sufficient for slow regulatory volume increase during aestivation in vivo. Osmotic swelling of the RBCs induced an incomplete regulatory volume decrease that was statistically significant after 180 rain. The RBCs of Protopterus were very large (mean cellular volume of 6939 ± 294 μm3) and possessed 23066 ± 7326 β-adrenoceptors cell-1 with a Kd value of 6.1 ± 3.2 nM. The number of receptors per unit surface area of lungfish RBCs was calculated to be twice that of trout RBCs and 70% that of cod RBCs. There was, however, no adrenergic stimulation of the NHE in either Protopterus or Lepidosiren. Acidification of the extracellular medium also failed to activate the NHE.

引用

页码：87 / 93

页数：6

共 38 条

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