In this study, we examined the effect of sepsis on the electrical properties of isolated ventricular myocytes. Sepsis was induced by cecal ligation and puncture (CLP). The control rats were sham-operated. Membrane potentials and ionic currents in isolated cardiac myocytes were measured by the tight-seal, whole-cell patch-clamp technique. The results show that the resting membrane potentials of heart cells were significantly lower in the septic group (18 hr post-CLP) than those in the control group. However, there was no significant difference in action potential duration of 50% and 90% repolarization between the two groups of cells. In voltage-clamp experiments, isoproterenol (10 nM), a β-adrenergic agonist, caused an increase in L-type calcium current (I(Ca,L)) in a similar magnitude in myocytes isolated from the control and septic rats. Furthermore, isoproterenol failed to modify the time constants for I(Ca,L) inactivation and the overall shape of current- voltage relationship for both groups of cells. These results indicate that formation of a GΩ seal and subsequent tight-seal whole-cell recording with patch-clamp technique can be performed in heart cells derived from CLP- induced septic rats, and that septic rat heart is capable of responding effectively to β-adrenergic stimulation.
|Number of pages||9|
|Publication status||Published - 1993|
All Science Journal Classification (ASJC) codes
- Cardiology and Cardiovascular Medicine