Table 2.

Parameters of portal vein contractility from WT and I-1^(−/−) mice

Parameters	WT	I-1(−/−)
Amplitude of force (mN mm−2)	20.24±1.53	15.27±1.36*
Tension–time integral (mN s mm−2)	245.1±21.1	195.5±20.0
+dF/dt(mN s−1 mm−2)	62.21±4.41	67.37±9.09
−dF/dt(mN s−1 mm−2)	−42.99±2.04	−45.89±4.44
Frequency (min−1)	2.46±0.15	2.17±0.12
Isoproterenol EC50(nm	3.5±0.2	10.4±1.4*

Baseline measurements were obtained from 10 WT and 10 I-1^(−/−) isometrically mounted portal veins, in parallel. ±dF/dt values were obtained from 4 WT and 4 I-1^(−/−) portal veins. Parameters are listed on the left with units of measure listed in parentheses. Baseline values are expressed as means ± s.e.m. Statistical significance (Student's unpaired test) is indicated by an asterisk.

^*P < 0.05.