Skip to Main Content
Table 1.

Rate of rise of contraction and of 50% relaxation at 0.2 Hz in untreated ventricle and atrial muscle from each species

Rpeak (mN mm-1 s-1)Rpeak→50% rel (mN mm-1 s-1)
Turtle   
    Ventricle 12.7±1.7 (1.3±0.1) 25.3±4.1 (1.3±0.1) 
    Atria 13.8±2.3 (1.4±0.3) 24.3±3.8 (1.2±0.2) 
Python   
    Ventricle 17.1±2.3 (1.6±0.2) 34.2±4.1 (1.3±0.1) 
    Atria 16.4±2.4 (1.9±0.4) 41.7±7.4 (1.2±0.2) 
Tegu lizard   
    Ventricle 16.9±4.3 (1.3±0.2) 26.1±6.8 (1.3±0.1) 
    Atria 18.3±3.1 (0.7±0.1) 38.3±8.4 (0.5±0.1) 
Varanid lizard   
    Ventricle 26.5±5.1 (1.2±0.1) 32.9±5.8 (1.2±0.1) 
    Atria (0.8 Hz) 31.1±11.1 (1.1±0.1) 43.2±13.5 (1.1±0.1) 
Rpeak (mN mm-1 s-1)Rpeak→50% rel (mN mm-1 s-1)
Turtle   
    Ventricle 12.7±1.7 (1.3±0.1) 25.3±4.1 (1.3±0.1) 
    Atria 13.8±2.3 (1.4±0.3) 24.3±3.8 (1.2±0.2) 
Python   
    Ventricle 17.1±2.3 (1.6±0.2) 34.2±4.1 (1.3±0.1) 
    Atria 16.4±2.4 (1.9±0.4) 41.7±7.4 (1.2±0.2) 
Tegu lizard   
    Ventricle 16.9±4.3 (1.3±0.2) 26.1±6.8 (1.3±0.1) 
    Atria 18.3±3.1 (0.7±0.1) 38.3±8.4 (0.5±0.1) 
Varanid lizard   
    Ventricle 26.5±5.1 (1.2±0.1) 32.9±5.8 (1.2±0.1) 
    Atria (0.8 Hz) 31.1±11.1 (1.1±0.1) 43.2±13.5 (1.1±0.1) 

Rpeak, rate of rise of contraction; Rpeak→50% rel, rate of 50% relaxation.

Turtle, Trachemys scripta (N=7); python, Python regius (N=7); tegu lizard, Tupinanvis merianae(N=6); varanid lizard, Varanus exanthematicus(N=8).

Values are means ± s.e.m. Values in parentheses denote fold change in rate from 0.2 Hz to maximal achievable frequency for each species and tissue type.

No significant differences in contraction kinetics were observed between atrial and ventricular tissue.

Close Modal

or Create an Account

Close Modal
Close Modal