Effects of hypoxia on acid-base balance, blood gases, catecholamines, and cutaneous ion exchange in the larval tiger salamander (Ambystoma tigrinum)
✍ Scribed by Talbot, Colleen R. ;Stiffler, Daniel F.
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 759 KB
- Volume
- 257
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
The effects of hypoxia on acid‐base balance and blood gases were examined in larval Ambystoma tigrinum. Environmental hypoxia (P = 24 mm Hg) resulted in a severe metabolic acidosis. During approximately 4 hr of hypoxia, arterial P fell from 23 to 8 mm Hg while P did not change; plasma lactate concentrations rose from 1.7 to 11 mM; pH fell from 7.9 to 7.3 and [HCO~3~^−^] decreased by 8.2 mM. After restoration of normoxia, P rose to 40 mm Hg within 1 hr. All variables returned to control levels between 4 and 24 hr. Circulating levels of norepinephrine were significantly increased and highly correlated with pH after 4 hr of hypoxia. Net and unidirectional Na^+^ and Cl^−^ flux rates were measured before, during, and after hypoxia to determine if cutaneous ion exchange is associated with the acid‐base disturbance. Neither Na^+^ nor Cl^−^ flux rates changed significantly during hypoxic exposure or recovery.