title: Electrophysiologic properties of isolated adult cardiomyocytes from septic rats.
abstract: 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 beta-adrenergic agonist, caused an increase in L-type calcium current (ICa,L) in a similar magnitude in myocytes isolated from the control and septic rats. Furthermore, isoproterenol failed to modify the time constants for ICa,L inactivation and the overall shape of current-voltage relationship for both groups of cells. These results indicate that formation of a G omega 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 beta-adrenergic stimulation.
authors.affiliation: Department of Physiology, Kaohsiung Medical College, Taiwan, R.O.C.
authors.forename: S N
authors.initials: SN
authors.lastname: Wu
authors.forename: S I
authors.initials: SI
authors.lastname: Lue
authors.forename: S L
authors.initials: SL
authors.lastname: Yang
authors.forename: H K
authors.initials: HK
authors.lastname: Hsu
authors.forename: M S
authors.initials: MS
authors.lastname: Liu
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000503:physiopathology*; D015220:Calcium Channels / Q000502:physiology; D002469:Cell Separation; D006321:Heart / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D015220:Calcium Channels