Socially-induced changes in sodium regulation affect the uptake of water-borne copper and silver in the rainbow trout, Oncorhynchus mykiss

2003 ◽  
Vol 135 (4) ◽  
pp. 393-403 ◽  
Author(s):  
K.A Sloman ◽  
T.P Morgan ◽  
D.G McDonald ◽  
C.M Wood
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Sodium Regulation ◽  
Induced Changes ◽  
Water Borne

Effects of temperature, adrenaline and ryanodine on power production in rainbow trout oncorhynchus mykiss ventricular trabeculae

1998 ◽  
Vol 201 (19) ◽  
pp. 2701-2710 ◽  
Author(s):  
HA Shiels ◽  
ED Stevens ◽  
AP Farrell
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Temperature Change ◽  
Power Production ◽  
Isometric Tension ◽  
Adrenergic Stimulation ◽  
Optimum Frequency ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Induced Changes ◽  
Power Curves

This study is the first to examine the contractility of teleost ventricular muscle in an oscillating muscle preparation. The experiments were designed to test the relative importance of Ca2+ released from the sarcoplasmic reticulum (SR) and Ca2+ influx across the sarcolemma (SL) to cardiac performance in rainbow trout Oncorhynchus mykiss. Adrenaline and ryanodine were used to modulate Ca2+ flux through the SL and SR, respectively. Experiments were conducted at two temperatures (12 degreesC and 22 degreesC) (1) to investigate the effect of an acute temperature change (from 12 degreesC to 22 degreesC) on power production, and (2) to test the effects of acute temperature change on the relative contributions of the SR and SL Ca2+ flux to power production. Concordant with isometric studies, the results showed that trans-sarcolemmal influx was the major source of Ca2+ (approximately 90 %) for cardiac power production at all temperatures. This SL Ca2+ influx was increased with adrenergic stimulation. The power curves generated in this study suggest an optimum frequency for power production of approximately 1.0 Hz at 12 degreesC, which corresponds well to typical in vivo heart rates for rainbow trout at that temperature. Further, this study indicated that temperature-induced changes in power output cannot be predicted from temperature-induced changes in isometric tension because the temperature-sensitivity of work and power proved to be greater than that of isometric tension. This finding is important because many previous studies have assessed cardiac contractility using only isometric tension.

The effects of 17β-estradiol injections on thyroid hormone deiodination pathways in liver and other tissues of female and male rainbow trout (Oncorhynchus mykiss) at different stages of sexual maturity

2005 ◽  
Vol 83 (4) ◽  
pp. 596-603 ◽  
Author(s):  
Susanna C Wiens ◽  
J Geoffrey Eales
Keyword(s):  
Rainbow Trout ◽  
Thyroid Hormone ◽  
Oncorhynchus Mykiss ◽  
Sexual Maturity ◽  
Developmental State ◽  
Liver Mass ◽  
Female Adult ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
17Β Estradiol ◽  
Induced Changes

The effects of two intraperitoneal injections of 17β-estradiol (E2) over 7 days were studied on thyroid hormone plasma levels and on activities of thyroxine (T4), 3,5,3'-triiodothyronine (T3), and 3,3',5'-triiodothyronine (rT3) outer-ring deiodination (ORD) and inner-ring deiodination (IRD) pathways in various tissues of female and male rainbow trout (Oncorhynchus mykiss (Walbaum, 1792)). E2 administered to adult females and males at different stages of sexual maturity increased liver mass, depressed plasma T3 levels with no change in plasma T4 levels, and severely decreased liver T4ORD activity. E2 also modestly depressed hepatic rT3ORD activity, but only at low substrate levels, and had no consistent effect on the hepatic IRD pathways. There were no E2-induced changes in brain, gill, or heart deiodination, but E2 increased kidney T3IRD activity. In contrast, an all-female stock of trout with rudimentary ovaries responded to E2 with an increase in liver mass but without change in plasma T4 and T3 levels or liver and brain deiodination activities. In conclusion, the decrease in plasma T3 levels in both male and female adult E2-injected trout may be due to both decreased hepatic T3 production and increased renal T3 degradation. However, thyroidal responses to E2 depend on physiological/developmental state and were absent in a highly immature all-female trout stock.

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