INTRODUCTION Recent studies reported that energetically deficient murine Pgc-1β-/- hearts replicate age-dependent atrial arrhythmic phenotypes associated with their corresponding clinical conditions, implicating action potential (AP) conduction slowing consequent upon reduced AP upstroke rates. MATERIALS AND METHODS We tested a hypothesis implicating Na+ current alterations as a mechanism und...

Sodium currents were studied in granule cells dissociated from rat cerebellum. Macroscopic currents were recorded using the patch-clamp technique. Sodium currents, which are TTX sensitive, reached a maximum peak value of 0.42 +/- 0.08 pA/microns2 at 18.4 +/- 2.2 mV (n = 6). Activation and inactivation kinetics and steady-state properties were described in terms of Hodgkin and Huxley parameters....

Neuroligins (Nlgns) are postsynaptic cell adhesion molecules that form transynaptic complexes with presynaptic neurexins and regulate synapse maturation and plasticity. We studied the impact of the loss of Nlgn4 on the excitatory and inhibitory circuits in somatosensory cortical slices of juvenile mice by electrically stimulating these circuits using a multi-electrode array and recording the sy...

The goal of this study was to analyze the effects of mibefradil on a human cardiac K(+) channel (hKv1.5) stably expressed in Chinese hamster ovary cells using the whole-cell configuration of the patch-clamp technique. Mibefradil inhibited in a concentration-dependent manner the hKv1.5 current with a K(D) value of 0.78 +/- 0.05 microM and a Hill coefficient of 0.97 +/- 0.06. Block induced by mib...

The CIC family is the superfamily of voltage-gated Cl- channels. Although the CIC channels expressed in Xenopus oocytes have been characterized, their channel properties are still poorly understood. We recently cloned a unique member of the CIC family, CIC-3, that is expressed abundantly in neurons. Its channel activity was regulated by phorbol esters. Now, we have established a stably transfec...

The effect of acidosis on Ca2+ uptake and release by the sarcoplasmic reticulum (SR) of rat ventricular myocytes has been investigated. Intracellular Ca2+concentration ([Ca2+]i) was monitored using fura 2; the L-type Ca2+ current ( I Ca) was monitored using the perforated patch-clamp technique. Acidosis was produced either by superfusing the cells with an acid solution (intracellular and extrac...

We previously reported that lysoplasmenylcholine (LPlasC) altered the action potential (AP) and induced afterdepolarizations in rabbit ventricular myocytes. In this study, we investigated how LPlasC alters excitation-contraction coupling using edge-motion detection, fura-PE3 fluorescent indicator, and perforated and whole cell patch-clamp techniques. LPlasC increased contraction, myofilament Ca...

Matrix synthesis by articular chondrocytes is sensitive to changes in intracellular pH (pH(i)), so characterising the membrane transport pathways that determine pH(i) is important for understanding how chondrocytes regulate the turnover of cartilage matrix. In the present study, the whole-cell patch-clamp technique has been employed to demonstrate the operation of voltage-activated H(+) channel...

Myocytes overlying a zone of infarction form the primary substrate for serious reentrant ventricular arrhythmias. In vitro and in vivo studies suggest that antiarrhythmic agents affect Na+ channels of cells from the epicardial border zone (EBZ) of the 5-day infarcted heart differently than they affect those of normal muscle. However, the mechanisms responsible for this difference remain unclear...

1. The electrophysiological properties of voltage-dependent sodium currents were studied in the human neuroblastoma cell line SH-SY5Y before and after in vitro differentiation with retinoic acid, with the use of the whole cell variant of the patch-clamp technique. 2. Voltage steps from a holding level of -90 mV to depolarizing potentials elicited, in both undifferentiated and differentiated cel...