In this study, we examined whether the adrenergic volume response of teleost erythrocytes is related to cell maturity. Rainbow trout (Oncorhynchus mykiss) were made anaemic by reducing their haematocrit to approximately 50 % of the original value. After 3–4 weeks, small, young erythrocytes were seen in the circulation. By measuring the volume distribution of blood samples from anaemic fish before and after noradrenaline stimulation (10 min, 10(−5)mol l(−1) final concentration), we were able to show that the volume response of young, immature erythrocytes to catecholamine stimulation was greater than that of mature erythrocytes. In addition, the membrane fluidity, measured using the steady-state fluorescence polarisation method, was greater in anaemic fish after 24 days of recovery from bleeding than in control fish. Since blood from anaemic fish contained a large fraction of immature erythrocytes, this result indicates that the fluidity of the membrane of immature erythrocytes is greater than that of mature erythrocytes.

Cossins
A. R.
,
Kilbey
R. V.
(
1989
).
The seasonal modulation of Na+/H+exchanger activity in trout erythrocytes
.
J. Exp. Biol
144
,
463
–.
Ferguson
R. A.
,
Tufts
B. L.
,
Boutilier
R. G.
(
1989
).
Energy metabolism in trout red cells: consequences of adrenergic stimulation in vivo and in vitro
.
J. Exp. Biol
143
,
133
–.
Gabbianelli
R.
,
Santroni
A. M.
,
Falcioni
G.
,
Bertoli
E.
,
Curatola
G.
,
Zolese
G.
(
1996
).
Physicochemical characterization of plasma membranes from density-separated trout erythrocytes
.
Arch. Biochem. Biophys
336
,
157
–.
Garcia-Romeu
F.
,
Motais
R.
,
Borgese
F.
(
1988
).
Desensitization by external Na of the cyclic AMP-dependent Na+/H+antiporter in trout red blood cells
.
J. Gen. Physiol
91
,
529
–.
Gilmour
K. M.
,
Didyk
N. E.
,
Reid
S. G.
,
Perry
S. F.
(
1994
).
Down-regulation of red blood cell-adrenoceptors in response to chronic elevation of plasma catecholamine levels in the rainbow trout
.
J. Exp. Biol
186
,
309
–.
Grinstein
S.
,
Goetz
J. D.
,
Furuya
W.
,
Rothstein
A.
,
Gelfand
E. W.
(
1984
).
Amiloride sensitive Na+—H+exchange in platelets and leukocytes: detection by electronic cell sizing
.
Am. J. Physiol
247
,
293
–.
Guizouarn
H.
,
Borgese
F.
,
Pellissier
B.
,
Garcia-Romeu
F.
,
Motais
R.
(
1995
).
Regulation of Na+/H+exchange activity by recruitment of new Na+/H+antiporters: Effect of calyculin A
.
Am. J. Physiol
268
,
434
–.
Guizouarn
H.
,
Motais
R.
(
1999
).
Swelling activation of transport pathways in erythrocytes: effects of Cl, ionic strength and volume changes
.
Am. J. Physiol
276
,
210
–.
Houston
A. H.
,
Murad
A.
(
1995
).
Erythrodynamics in fish: Recovery of the goldfish Carassius auratus from acute anemia
.
Can. J. Zool
73
,
411
–.
Keen
J. E.
,
Viazon
D.-M.
,
Farrell
A. P.
,
Tibbits
G. F.
(
1993
).
Thermal acclimation alters both adrenergic sensitivity and adrenoceptor density in cardiac tissue of rainbow trout
.
J. Exp. Biol
181
,
27
–.
Lecklin
T.
,
Nikinmaa
M.
(
1999
).
Seasonal and temperature effects on the adrenergic responses of Arctic charr (Salvelinus alpinus) erythrocytes
.
J. Exp. Biol
202
,
2233
–.
Lee
P.
,
Miles
P. R.
(
1972
).
Density distribution and cation composition of red blood cells in newborn puppies
.
J. Cell. Physiol
79
,
377
–.
Motais
R.
,
Fievet
B.
,
Garcia-Romeu
F.
,
Thomas
S.
(
1989
).
Na+—H+exchange and pH regulation in red blood cells: role of uncatalyzed H2CO3dehydration
.
Am. J. Physiol
256
,
728
–.
Motais
R.
,
Guizouarn
H.
,
Garcia-Romeu
F.
(
1991
).
Red cell volume regulation: the pivotal role of ionic strength in controlling swelling-dependent transport systems
.
Biochim. Biophys. Acta
1075
,
169
–.
Nikinmaa
M.
,
Jensen
F. B.
(
1986
).
Blood oxygen transport and acid—base status of stressed trout (Salmo gairdnerii): Pre-and postbranchial values in winter fish
.
Comp. Biochem. Physiol
84
,
391
–.
Nikinmaa
M.
,
Soivio
A.
,
Railo
E.
(
1981
).
Blood volume of Salmo gairdneri: Influence of ambient temperature
.
Comp. Biochem. Physiol
69
,
767
–.
Perry
S. F.
,
Reid
S. G.
,
Salama
A.
(
1996
).
The effects of repeated physical stress on the-adrenergic response of the rainbow trout red blood cell
.
J. Exp. Biol
199
,
549
–.
Phillips
M. C. L.
,
Moyes
C. D.
,
Tufts
B. L.
(
2000
).
The effects of cell ageing on metabolism in rainbow trout (Oncorhynchus mykiss) red blood cells
.
J. Exp. Biol
203
,
1039
–.
Raynard
R. S.
,
Cossins
A. R.
(
1991
).
Homeoviscous adaptation and thermal compensation of sodium pump of trout erythrocytes
.
Am. J. Physiol
260
,
916
–.
Reid
S. D.
,
Lebras
Y.
,
Perry
S. F.
(
1993
).
The in vitro effect of hypoxia on the trout erythrocyte-adrenergic signal transduction system
.
J. Exp. Biol
176
,
103
–.
Reid
S. D.
,
Moon
T. W.
,
Perry
S. F.
(
1992
).
Rainbow trout hepatocytes-adrenoceptors, catecholamine responsiveness and effects of cortisol
.
Am. J. Physiol
262
,
794
–.
Reid
S. D.
,
Perry
S. F.
(
1991
).
The effects and physiological consequences of raised levels of cortisol on rainbow trout (Onchorhynchus mykiss) erythrocyte-adrenoceptors
.
J. Exp. Biol
158
,
217
–.
Soivio
A.
,
Nyholm
K.
,
Westman
K.
(
1975
).
A technique for repeated sampling of the blood of individual resting fish
.
J. Exp. Biol
63
,
207
–.
Tolkovsky
A. M.
,
Levitzki
A.
(
1978
).
Mode of coupling between the-adrenergic receptor and adenylate cyclase in turkey erythrocytes
.
Biochemistry
17
,
3795
–.
This content is only available via PDF.