Cardiovascular status of 5°C- and 21°C-acclimated normoxic turtles before and after intra-arterial injection of the α-adrenergic antagonist phentolamine
| Acclimation temperature . | Drug injected . | Heart rate fH (beats min−1) . | Systemic stroke volume Vssys (ml kg−1) . | Systemic cardiac output Q̇sys(ml min−1 kg−1) . | Systemic blood pressure Psys (kPa) . | Systemic power output POsys (mW g−1) . | Systemic resistance Rsys (kPa ml−1 min kg) . |
|---|---|---|---|---|---|---|---|
| 5°C | Routine normoxic | 4.1±0.4* | 2.31±0.37 | 9.2±1.3* | 1.52±0.11* | 0.126±0.025* | 0.18±0.03* |
| Phentolamine (3 mg kg−1) | 4.3±0.5 | 3.21±0.57† | 12.8±1.8† | 0.98±0.06† | 0.108±0.015 | 0.08±0.01† | |
| 21°C | Routine normoxic | 21.3±2.0 | 1.95±0.29 (5) | 42.9±8.0 (5) | 2.83±0.53 | 1.508±0.323 (5) | 0.09±0.02 (5) |
| Phentolamine (3 mg kg−1) | 22.6±3.4 | 2.84±0.90 (4) | 63.5±18.6 (4) | 2.08±0.33 | 1.777±0.591 (4) | 0.06±0.02 (4) |
| Acclimation temperature . | Drug injected . | Heart rate fH (beats min−1) . | Systemic stroke volume Vssys (ml kg−1) . | Systemic cardiac output Q̇sys(ml min−1 kg−1) . | Systemic blood pressure Psys (kPa) . | Systemic power output POsys (mW g−1) . | Systemic resistance Rsys (kPa ml−1 min kg) . |
|---|---|---|---|---|---|---|---|
| 5°C | Routine normoxic | 4.1±0.4* | 2.31±0.37 | 9.2±1.3* | 1.52±0.11* | 0.126±0.025* | 0.18±0.03* |
| Phentolamine (3 mg kg−1) | 4.3±0.5 | 3.21±0.57† | 12.8±1.8† | 0.98±0.06† | 0.108±0.015 | 0.08±0.01† | |
| 21°C | Routine normoxic | 21.3±2.0 | 1.95±0.29 (5) | 42.9±8.0 (5) | 2.83±0.53 | 1.508±0.323 (5) | 0.09±0.02 (5) |
| Phentolamine (3 mg kg−1) | 22.6±3.4 | 2.84±0.90 (4) | 63.5±18.6 (4) | 2.08±0.33 | 1.777±0.591 (4) | 0.06±0.02 (4) |
Values are means ± s.e.m. (N=6, unless otherwise indicated in parentheses).
Significant differences (P<0.05) between acclimation temperature for routine normoxic cardiovascular status.
Significant differences (P<0.05) between routine normoxic and phentolamine for each variable at each acclimation temperature.