Gilson N, Crozatier B, Laplace M
INSERM U2, Hôpital Léon Bernard, Limeil-Brévannes, France.
Cardiovasc Res. 1989 Jan;23(1):7-15. doi: 10.1093/cvr/23.1.7.
A model for the study of left ventricular (LV) contractility in a small species was developed using conscious rabbits previously instrumented with a LV catheter and ultrasonic crystals measuring LV internal diameter. Afterload increase produced by methoxamine infusion was associated with a reduction in heart rate from 272(SEM18) to 214(20) beats.min-1, p less than 0.01; and an increase in LV end systolic pressure from 76.3(4.1) to 101(6.5) mm Hg, p less than 0.001, and in end systolic diameter from 8.7(0.7) to 9.9(0.7) mm, p less than 0.01. For matched end systolic pressure and heart rate, the increase in inotropic state produced by noradrenaline infusion significantly shifted the pressure-diameter relation to the left. Similarly, end systolic pressure and diameter were significantly lowered by sodium nitroprusside infusion, with a reflex increase of heart rate; and a decrease in inotropic state produced by verapamil infusion was demonstrated by a significantly larger end systolic diameter for matched end systolic pressure and heart rate. The pressure-diameter relation was not modified by volume loading, which increased end diastolic diameter by 9.6(1.1)% with no evidence of a Bainbridge reflex. The mild depressant effect of diltiazem was not detected by peak dP/dt changes but was demonstrated by the analysis of end systolic pressure-diameter relations. The instrumented rabbit thus appears to be a sensitive model for studying LV function and the cardiovascular effects of drugs.
利用事先植入左心室导管和超声晶体以测量左心室内径的清醒家兔，建立了一个用于研究小型动物左心室（LV）收缩性的模型。静脉输注甲氧明导致后负荷增加，同时心率从272（标准误18）降至214（20）次/分钟，p<0.01；左心室收缩末期压力从76.3（4.1）升至101（6.5）mmHg，p<0.001，收缩末期直径从8.7（0.7）增至9.9（0.7）mm，p<0.01。对于匹配的收缩末期压力和心率，静脉输注去甲肾上腺素所产生的心肌收缩力增加使压力-直径关系显著左移。同样，静脉输注硝普钠可使收缩末期压力和直径显著降低，同时心率反射性增加；对于匹配的收缩末期压力和心率，静脉输注维拉帕米所产生的心肌收缩力降低表现为收缩末期直径显著增大。容量负荷未改变压力-直径关系，容量负荷使舒张末期直径增加9.6（1.1）%，未发现有贝恩布里奇反射的证据。地尔硫䓬的轻度抑制作用未通过峰值dP/dt变化检测到，但通过收缩末期压力-直径关系分析得以证实。因此，植入仪器的家兔似乎是研究左心室功能和药物心血管效应的敏感模型。
