The patch clamp technique, developed in late 1970s, started a new period of experimental cardiac electrophysiology enabling measurement of ionic currents on isolated cardiomyocytes down to the level of single channels. Since that time, the technique has been substantially improved by development of several upgraded modifications providing so far unavailable data (e.g. action potential clamp, dynamic clamp, high-resolution scanning patch clamp), or facilitating the patch clamp technique by increasing its efficiency (planar patch clamp, automated patch clamp). The current review summarizes the leading new patch clamp based techniques used in cardiac cellular electrophysiology, their principles and prominent related papers.
- MeSH
- Action Potentials physiology MeSH
- Equipment Design trends MeSH
- Ion Channel Gating physiology MeSH
- Ion Channels metabolism MeSH
- Humans MeSH
- Membrane Potentials physiology MeSH
- Patch-Clamp Techniques instrumentation trends MeSH
- Microelectrodes trends MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Patch clamp method developed more than 30 years ago is widely used for investigation of cellular excitability manifested as transmembrane ionic current and/or generation of action potentials. This technique could be applied to measurement of ionic currents flowing through individual (single) ion channels or through the whole assembly of ion channels expressed in the whole cell. Whole cell configuration is more common for measurement of ion currents and the only one enabling measurement of action potentials. This method allows detailed analysis of mechanisms and structural determinants of voltagedependent gating of ion channels as well as regulation of channel activity by intracellular signaling pathways and pharmacological agents.
- MeSH
- Action Potentials MeSH
- Models, Biological MeSH
- Cell Membrane metabolism MeSH
- Financing, Organized MeSH
- Ion Channel Gating MeSH
- Ion Channels metabolism MeSH
- Humans MeSH
- Membrane Potentials MeSH
- Patch-Clamp Techniques MeSH
- Calcium Signaling MeSH
- Calcium Channels, T-Type metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Review MeSH
We have developed an improved technique for fast cooling and heating of solutions superfusing isolated cells under patch-clamp or calcium imaging conditions. The system meets the requirements for studying temperature dependency of all kinds of ion channels, in particular temperature-gated ion channels. It allows the application of temperature changes within a range of 5-60 degrees C at maximum rates of -40 degrees C/s to 60 degrees C/s. Barrels filled with different solutions are connected to a manifold consisting of seven silica capillaries (320 microm inner diameter, i.d.). A common outlet consists of a glass capillary through which the solutions are applied onto the cell surface. The upper part of this capillary is embedded in a temperature exchanger driven by a miniature Peltier device which preconditions the temperature of the passing solution. The lower part of the capillary carries an insulated copper wire, densely coiled over a length of 7 mm, and connected to a dc current source for resistive heating. The Peltier device and the heating element are electrically connected to the headstage probe which is fixed on to a micromanipulator for positioning of the manifold. The temperature of the flowing solution is measured by a miniature thermocouple inserted into the common outlet capillary near to its orifice which is placed at a distance of less than 100 microm from the surface of the examined cell. The temperature is either manually controlled by voltage commands or adjusted via the digital-to-analog converter of a conventional data acquisition interface. Examples are given of using the device in patch-clamp studies on heterologously expressed TRPV1, TRPM8, and on cultured rat sensory neurons.
- MeSH
- Action Potentials physiology MeSH
- Equipment Failure Analysis MeSH
- Cell Culture Techniques methods instrumentation MeSH
- Equipment Design MeSH
- Financing, Organized MeSH
- Cells, Cultured MeSH
- Humans MeSH
- Membrane Potentials physiology MeSH
- Patch-Clamp Techniques methods instrumentation MeSH
- Neurons, Afferent physiology MeSH
- Cold Temperature MeSH
- Perfusion instrumentation MeSH
- Environment, Controlled MeSH
- Hot Temperature MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Evaluation Study MeSH
Highlights Simultaneous epileptiform LFPs and single-cell activity can be recorded in the membrane chamber.Interneuron firing can be linked to epileptiform high frequency activity.Fast ripples, unique to chronic epilepsy, can be modeled in ex vivo tissue from TeNT-treated rats. Traditionally, visually-guided patch clamp in brain slices using submerged recording conditions has been required to characterize the activity of individual neurons. However, due to limited oxygen availability, submerged conditions truncate fast network oscillations including epileptiform activity. Thus, it is technically challenging to study the contribution of individual identified neurons to fast network activity. The membrane chamber is a submerged-style recording chamber, modified to enhance oxygen supply to the slice, which we use to demonstrate the ability to record single-cell activity during in vitro epilepsy. We elicited epileptiform activity using 9 mM potassium and simultaneously recorded from fluorescently labeled interneurons. Epileptiform discharges were more reliable than in standard submerged conditions. During these synchronous discharges interneuron firing frequency increased and action potential amplitude progressively decreased. The firing of 15 interneurons was significantly correlated with epileptiform high frequency activity (HFA; ~100-500 Hz) cycles. We also recorded epileptiform activity in tissue prepared from chronically epileptic rats, treated with intrahippocampal tetanus neurotoxin. Four of these slices generated fast ripple activity, unique to chronic epilepsy. We showed the membrane chamber is a promising new in vitro environment facilitating patch clamp recordings in acute epilepsy models. Further, we showed that chronic epilepsy can be better modeled using ex vivo brain slices. These findings demonstrate that the membrane chamber facilitates previously challenging investigations into the neuronal correlates of epileptiform activity in vitro.
- MeSH
- Electrocorticography MeSH
- Epilepsy * diagnostic imaging MeSH
- Interneurons MeSH
- Rats MeSH
- Patch-Clamp Techniques * methods MeSH
- Disease Models, Animal MeSH
- Cerebral Cortex diagnostic imaging MeSH
- In Vitro Techniques methods MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
