Table 2.

Contractile parameters of isovolumetrically contracting mouse hearts after administration of 0.1 μmol l ⁻¹of ISO paced at 10 Hz. For each heart, parameters were obtained at LV balloon volume that produced the maximum developed pressure

						ANOVA P-value
Parameters	NTG (n = 16)	WT-Tg (n = 6)	Control (NTG + WT-Tg) (n = 22)	I79N-Tg (n = 10)	R278C-Tg (n = 6)	NTG, WT, I79N, R278C	Control, I79N, R278C
End-diastolic pressure (mmHg)	14.8 ± 1.6	10.1 ± 2.9	13.5 ± 1.5	20.2 ± 3.22*	11.2 ± 1.7	0.0434	0.0428
Developed pressure (mmHg)	108 ± 3.98	106 ± 8.13	107 ± 3.55	90.74 ± 5.3‡*†	110 ± 2.08	0.0435	0.0192
Peak +dP dt−1 (mmHg s−1)	6664 ± 317	6636 ± 583	6656 ± 272	5572 ± 460	6757 ± 478	0.1842	0.0857
Normalized +dP dt−1	61.54 ± 0.91	62.4 ± 1.16	61.8 ± 0.72	60.7 ± 2	61 ± 3.17	0.9272	0.8344
Peak −dP dt−1 (mmHg s−1)	5270 ± 221	5209 ± 426	5254 ± 193	3942 ± 290‡§*†	5236 ± 324	0.0049	0.0015
Normalized −dP dt−1	49 ± 0.85	49 ± 1.69	49 ± 0.75	43 ± 1.56‡§*	47.5 ± 2.11	0.0083	0.0026
Ratio +dP dt−1
to −dP dt−1	1.27 ± 0.03	1.27 ± 0.04	1.27 ± 0.02	1.41 ± 0.06‡*	1.29 ± 0.02	0.0682	0.0165
TTR 90% (ms)	29 ± 0.5	29 ± 1.1	29 ± 0.4	34 ± 1.4‡§*†	32 ± 1.0‡*	0.0010	0.0002
Balloon volume (μl)	28.5 ± 1.17	28.3 ± 1.05	28.45 ± 0.88	23.7 ± 0.72‡§*†	27.7 ± 1.58	0.0209	0.0069

Data are mean ±s.e.m.; control = combined data from NTG and WT-Tg

^‡P < 0.05 versus NTG

^§P < 0.05 versus WT

^*P < 0.05 versus control

^†P < 0.05 I79N-Tg versus R278C-Tg.