RAINBOW TROUT (SALMO GAIRDXERI) AND STARRY FLOUNDER (PLATICHTHYS STELLATUS)

In vitiv, exogenous adrenaline reduced the Bohr and Root shifts caused by elevated PaCO) and depressed plasma pH in rainbow trout blood, but not in starry flounder blood. In vivo immediately after exercise, plasma adrenaline (Ad) and noradrenaline (NAd) increased about 12-fold in rainbow trout. Associated with this catecholamine mobilization was a significant haemoconcentration, red blood cell (RBC) swelling and a reduction in RBC [NTP]; the latter was larger than that explained by cell swelling alone, indicating metabolic degradation of nucleoside triphosphate (NTP). RBC intracellular pH (pH,) fell only slightly after exercise (0-07 units) at Oh, but was restored by 0'5h in the face of a large plasma acidosis (0'4 units). [C>2]/[Hb] fell significantly, but this decline may have been due in part to the significant reduction in Pa(). The reduction in [O2]/[Hb] was less than predicted from in vitm 02-dissociation curves at low (O'Snmoll"') catecholamine levels, but similar to that predicted at high (90nmoll~') catecholamine levels. In flounder, resting Ad and NAd levels were about 10 times those in trout and did not change significantly after exercise. As a consequence, there was no reduction in RB