The effects of blood CO 2 reaction rates on CO 2 removal from muscle in exercised trout

Abstract

The purpose of this study was to examine the relative importance of some of the factors potentially limiting carbon dioxide (CO 2) removal from the white muscle in the rainbow trout following exhaustive exercise. Inhibition of red blood cell carbonic anhydrase (CA) activity by acetazolamide (Az) infusion following exercise caused a large increase in both arterial and muscle P CO 2 indicating retention of CO 2 in the animal. Despite the increase in muscle P CO 2 , there was no significant decrease in muscle pH in Az-treated fish, probably due to the relatively high buffer capacity of white muscle. The presence of CA in the plasma had a transient, significant effect on blood P CO 2 and pH, but no significant effect on muscle P CO 2 or pH. Thus, CA treatment transiently enhances CO 2 removal from the animal following exercise, but the extracellular catalysis of the CO 2 reactions in the plasma does not appear to have a large impact on CO 2 removal from the tissues.