THE EFFECTS OF BLOOD CO2 REACTION-RATES ON CO2 REMOVAL FROM MUSCLE INEXERCISED TROUT

The purpose of this study was to examine the relative importance of so me of the factors potentially limiting carbon dioxide (CO2) removal fr om the white muscle in the rainbow trout following exhaustive exercise . Inhibition of red blood cell carbonic anhydrase (CA) activity by ace tazolamide (At) infusion following exercise caused a large increase in both. arterial and muscle P-CO2 indicating retention of CO2 in the an imal. Despite the increase in muscle P-CO2, there was no significant d ecrease in muscle pH in At-treated fish, probably due to the relativel y high buffer capacity of white muscle. The presence of CA in the plas ma had a transient, significant effect on blood P-CO2 and pH, but no s ignificant effect on muscle P-CO2 or pH. Thus, CA treatment transientl y enhances CO2 removal from the animal following exercise, but the ext racellular catalysis of the CO2 reactions in the plasma does not appea r to have a large impact on CO2 removal from the tissues.