The effects of exposure to hypercarbia (nominal Pwco2=6 Torr) and acetazolamide treatment (30 mg kg−1) on arterial blood pH, CO2 tension and HCO3− concentration
| . | Control . | . | . | Hypercarbia-exposed . | . | . | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| . | Pre-exposure . | Pre-Az . | Post-Az . | Pre-exposure . | Pre-Az . | Post-Az . | ||||
| pHa | 7.78±0.02a | 7.75±0.02a | 7.57±0.01b | 7.76±0.02a | 7.58±0.01b,* | 7.40±0.01c,* | ||||
| Paco2 (Torr) | 2.97±0.24a | 3.36±0.30a | 4.96±0.22b | 3.35±0.29a | 7.73±0.15b,* | 12.15±0.17c,* | ||||
| [HCO3−] (mmol 1−1) | 7.68±0.20a | 7.94±0.28a | 7.89±0.26a | 8.07±0.27a | 12.3±0.07b,* | 12.6±0.43b,* | ||||
| . | Control . | . | . | Hypercarbia-exposed . | . | . | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| . | Pre-exposure . | Pre-Az . | Post-Az . | Pre-exposure . | Pre-Az . | Post-Az . | ||||
| pHa | 7.78±0.02a | 7.75±0.02a | 7.57±0.01b | 7.76±0.02a | 7.58±0.01b,* | 7.40±0.01c,* | ||||
| Paco2 (Torr) | 2.97±0.24a | 3.36±0.30a | 4.96±0.22b | 3.35±0.29a | 7.73±0.15b,* | 12.15±0.17c,* | ||||
| [HCO3−] (mmol 1−1) | 7.68±0.20a | 7.94±0.28a | 7.89±0.26a | 8.07±0.27a | 12.3±0.07b,* | 12.6±0.43b,* | ||||
Mean values ± 1 s.e.m., N=8 for both control and hypercarbia-exposed fish.
1 Torr=133.3 Pa. pHa, arterial pH; Paco2,arterial blood partial pressure of CO2;[HCO3−], arterial blood HCO3− concentration; Az, acetazolamide.
Data were analyzed by two-way RM ANOVA with treatment group (control vs hypercarbia-exposed) and sampling time (pre-exposure, pre-Az or post-Az) as factors. For all three variables (pHa, Paco2 and [HCO3−]), P<0.001 for both factors and interactions between these factors. Within a treatment group, values that do not share a letter are significantly different from one another, while an asterisk (*) indicates a significant difference from the corresponding value for the control group at a given sampling time.