ISSN:
1432-136X
Keywords:
Na K-pump
;
Na/H exchange
;
Catecholamines
;
Cell volume
;
Fish erythrocytes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract β-Adrenergic- and volume-dependent regulation of 22Na influx and 86Rb influx and efflux in erythrocytes of brown trout (Salmo trutta m. lacustris) were studied. Norepinephrine (10-6 mol·1-1) increased the rate of 22Na influx 10-to 20-fold via the activation of a Na/H exchanger (ethyl isopropyl amiloride inhibited component of 22Na influx). Unlike carp erythrocytes the activity of the Na, K-pump (ouabain-inhibited 86Rb influx) was only slightly (25–35%) increased by norepinephrine. The norepinephrine-induced increment of Na, K-pump activity was completely abolished by ethyl isopropyl amiloride thus indicating that this effect was mediated by Na/H exchanger-induced increase of intracellular Na+ concentration. Cell shrinkage in hyperosmotic media resulted in a several-fold activation of the Na/H exchanger. Cell swelling in hypotonic media increased both the rate of K, Cl-cotransport [((dihydroindenyl)oxy)alcanaic acidsensitive components of 86Rb influxe and efflux] and passive permeability (leakage) of erythrocyte membranes for Na+ and K+. No volume-dependent regulation of Na, K, 2Cl-cotransport (bumetanide-sensitive components of 86Rb fluxes) was found. It may be concluded that the regulation of monovalent cation transport in erythrocytes of fast-moving (carnivorous) brown trout differs essentially from that in slowly moving (herbivorous) carp.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00301655
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