Dynamic clamp, a hybrid-computational-experimental technique that has been used to elucidate ionic mechanisms underlying cardiac electrophysiology, is emerging as a promising tool in the discovery of potential anti-arrhythmic targets and in pharmacological safety testing. Through the injection of computationally simulated conductances into isolated cardiomyocytes in a real-time continuous loop,...

The traditional method of recording ionic currents in neurons has been with voltage-clamp steps. Other waveforms such as action potentials (APs) can be used. The AP clamp method reveals contributions of ionic currents that underlie excitability during an AP (Bean BP. Nat Rev Neurosci 8: 451-465, 2007). A novel usage of the method is described in this report. An experimental recording of an AP f...

Patients carrying the heterozygous A414G mutation in HCN4 gene, which encodes protein, demonstrate moderate to severe bradycardia of heart. Tetramers subunits compose ion channels sinus node that carry hyperpolarization-activated ‘funny’ current (If), also named ‘pacemaker current’. If plays an essential modulating role pacemaker activity. To assess mechanism by results bradycardia, we first pe...

Taste sensory responses from the chorda tympani nerve of the rat were recorded with the lingual receptive field under current or voltage clamp. Consistent with previous results (Ye, Q., G. L. Heck, and J. A. DeSimone. 1993. Journal of Neurophysiology. 70:167-178), responses to NaCl were highly sensitive to lingual voltage clamp condition. This can be attributed to changes in the electrochemical...

Neuronal activity is dominated by synaptic inputs from excitatory or inhibitory neural circuits. With the development of in vivo patch-clamp recording, especially in vivo voltage-clamp recording, researchers can not only directly measure neuronal activity, such as spiking responses or membrane potential dynamics, but also quantify synaptic inputs from excitatory and inhibitory circuits in livin...

The R20 neurons of Aplysia exhibit frequency-dependent spike broadening. Previously, we had used two-electrode voltage clamp to examine the mechanisms of this spike broadening (Ma and Koester, 1995). We identified three K+ currents that mediate action-potential repolarization: a transient A-type K+ current (I(Adepol)), a delayed rectifier current (IK-V), and a Ca(2+)-sensitive K+ current(IK-CA)...

Sympathetic stimulation induces weak salivation compared with parasympathetic stimulation. To clarify this phenomenon in salivary glands, we investigated cAMP-induced modulation of Ca(2+)-activated Cl(-) secretion from rat parotid and submandibular acinar cells because fluid secretion from salivary glands depends on the Cl(-) secretion. Carbachol (Cch), a Ca(2+)-increasing agent, induced hyperp...

BACKGROUND Kilohertz-frequency electric field stimulation (kEFS) applied to the spinal cord can reduce chronic pain without causing the buzzing sensation (paresthesia) associated with activation of dorsal column fibers. This suggests that high-rate spinal cord stimulation (SCS) has a mode of action distinct from conventional, parasthesia-based SCS. A recent study reported that kEFS hyperpolariz...

Effects of two general anesthetics, halothane and thiamylal, on the fast sodium inward current (INa) of enzymatically isolated single rat ventricular cells were studied under current clamp and voltage clamp conditions. A suction pipette technique was used for potential measurement, current injection and internal perfusion of isolated cells. In current clamp experiments, sodium action potential ...

royan b 1 stem cell can be differentiated to specialized cell types including cardiomyocytes. this developmental change is accompanied with expression of various k + channel types. the aim of this study was to detect functional expression of k + currents from stem cell stage and one week and two weeks after differentiation into cardiomyocyte. mouse stem cell derived cardiomyocytes (es-cardiomyo...