|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Acid-Base and Ionic Regulation in the American Eel (Anguilla Rostrata) During and after Prolonged Aerial Exposure: Branchial and Renal Adjustments
1 Department of Biology, University of Ottawa, 30 Somerset E, Ottawa, Ontario, Canada, KIN 6X5
To whom reprint request should be addressed.
The involvement of the gill and kidney in acid-base regulation was examined in the American eel, Anguilla rostrata, during 36h of continuous air-exposure and subsequent return to water. While in air, eels developed a severe mixed respiratory/- metabolic acidosis. Renal acid excretion increased only slightly during the latter stages of air-exposure. A pronounced reduction in urine flow rate was important to minimize dehydration but essentially eliminated the kidney as a route for excess acid excretion. Upon return to the water, eels had accrued an extracellular metabolic acid load of 9.53 mmol 1-1. The metabolic acid was cleared from the extracellular compartment at an exceptionally low rate (approximately 70µmol kg-1 h-1) and about 50 % of the acid load remained after 18 h of recovery in water. The clearance of metabolic acid was accounted for by enhanced branchial acid excretion which was related primarily to adjustments of unidirectional Na+ fluxes. Unidirectional Cl- fluxes were undetectable using radiotracer methods. We speculate that the inefficiency of acid-base regulation in the eel compared to other teleosts is, in part, related to the absence of significant branchial C1-/HCO3- exchange.
Key words: Anguilla rostrata, blood, gill, kidney, air-breathing, acid-base, ion fluxes
Accepted on June 29, 1987
