Patch clamp

About: Patch clamp is a research topic. Over the lifetime, 11186 publications have been published within this topic receiving 518317 citations. The topic is also known as: patch clamp technique.

Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.

Abstract: 1. The extracellular patch clamp method, which first allowed the detection of single channel currents in biological membranes, has been further refined to enable higher current resolution, direct membrane patch potential control, and physical isolation of membrane patches. 2. A description of a convenient method for the fabrication of patch recording pipettes is given together with procedures followed to achieve giga-seals i.e. pipette-membrane seals with resistances of 10(9) - 10(11) omega. 3. The basic patch clamp recording circuit, and designs for improved frequency response are described along with the present limitations in recording the currents from single channels. 4. Procedures for preparation and recording from three representative cell types are given. Some properties of single acetylcholine-activated channels in muscle membrane are described to illustrate the improved current and time resolution achieved with giga-seals. 5. A description is given of the various ways that patches of membrane can be physically isolated from cells. This isolation enables the recording of single channel currents with well-defined solutions on both sides of the membrane. Two types of isolated cell-free patch configurations can be formed: an inside-out patch with its cytoplasmic membrane face exposed to the bath solution, and an outside-out patch with its extracellular membrane face exposed to the bath solution. 6. The application of the method for the recording of ionic currents and internal dialysis of small cells is considered. Single channel resolution can be achieved when recording from whole cells, if the cell diameter is small (less than 20 micrometer). 7. The wide range of cell types amenable to giga-seal formation is discussed.

Single-channel recording

Abstract: A Practical Guide to Patch Clamping R. Penner. Tightseal Wholecell Recording A. Marty, E. Neher. Guide to Data Acquisition and Analysis S.H. Heinemann. Electronic Design of the Patch Clamp F.J. Sigworth. Low Noise Recording K. Benndorf. Voltage Offsets in Patch Clamp Experiments E. Neher. Techniques for Membrane Capacitance Measurements K.D. Gillis. Patch Pipette Recordings from the Soma, Dendrites and Axon of Neurons in Brain Slices B. Sakmann, G. Stuart. Patchclamp and Calcium Imaging in Brain Slices J. Eilers, et al. Fast Application of Agonists to Isolated Membrane Patches P. Jonas. Electrochemical Detection of Secretion from Single Cells R.H. Chow, L. von Ruden. Technical Approaches to Studying Specific Properties of Ion Channels in Plants R. Hedrich. The Giant Membrane Patch D.W. Hilgemann. A Fast Pressureclamp Technique for Studying Mechanogated Channels D.W. McBride, O.P. Hamill. Electrophysiological Recordings from Xenopus oocytes W. Stuhmer, A.B. Parekh. PCR Analysis of Ion Channel Expression in Single Neurons of Brain Slices H. Monyer, P. Jonas. 3 additional articles. Index.

Calcium channels activated by hydrogen peroxide mediate abscisic acid signalling in guard cells

Abstract: Drought is a major threat to agricultural production. Plants synthesize the hormone abscisic acid (ABA) in response to drought, triggering a signalling cascade in guard cells that results in stomatal closure, thus reducing water loss. ABA triggers an increase in cytosolic calcium in guard cells ([Ca2+]cyt) that has been proposed to include Ca2+ influx across the plasma membrane. However, direct recordings of Ca2+ currents have been limited and the upstream activation mechanisms of plasma membrane Ca2+ channels remain unknown. Here we report activation of Ca2+-permeable channels in the plasma membrane of Arabidopsis guard cells by hydrogen peroxide. The H2O2-activated Ca2+ channels mediate both influx of Ca2+ in protoplasts and increases in [Ca2+]cyt in intact guard cells. ABA induces the production of H2O2 in guard cells. If H2O2 production is blocked, ABA-induced closure of stomata is inhibited. Moreover, activation of Ca2+ channels by H2O2 and ABA- and H2O2-induced stomatal closing are disrupted in the recessive ABA-insensitive mutant gca2. These data indicate that ABA-induced H2O2 production and the H2O2-activated Ca2+ channels are important mechanisms for ABA-induced stomatal closing.

Muscarinic activation of ionic currents measured by a new whole-cell recording method

Abstract: A new method is described as an alternative to whole-cell recording in order to prevent "wash-out" of the muscarinic response to acetylcholine (ACh) in rat lacrimal gland cells. The membrane of a cell-attached patch is permeabilized by nystatin in the patch pipette, thus providing electrical continuity between the pipette and the cytoplasm of the cell without the loss or alteration of cytoplasmic compounds necessary for the maintenance of the response to ACh. With normal whole-cell recording in these cells, the response to ACh, seen as the activation of Ca-activated K and Cl currents, lasts for approximately 5 min. With the nystatin method, the response is not diminished after 1 h. Nystatin, applied extracellularly, is shown to cause a rapid and reversible increase of membrane conductance to cations. In the absence of wash-out, we were able to obtain dose-response curves for the effect of ACh on Ca-activated K currents. An increase of [ACh] caused an increase in the K current, with apparent saturation at concentrations above approximately 1 microM ACh. The delay between ACh application and the activation of K current was inversely related to [ACh] and reached a minimum value of 0.7-1.0 s at high [ACh].

GABAergic cell subtypes and their synaptic connections in rat frontal cortex.

Abstract: Physiological, morphological and immunohistochemical characteristics of non-pyramidal cells in frontal cortex of young rats were studied in vitro by whole-cell recording and biocytin injection. Several groups of GABAergic non-pyramidal cells were identified: (i) parvalbumin fast-spiking (FS) cells with low input resistances and spikes of short duration, including extended plexus (basket) cells and chandelier cells. These cells showed abrupt episodes of non-adapting repetitive discharges; (ii) late-spiking (LS) cells exhibiting slowly developing ramp depolarizations, including neurogliaform cells; (iii) the remaining groups contained both burst-spiking (BS) or regular-spiking (RS) non-pyramidal (NP) cells. BSNP cells exhibited bursting activity (two or more spikes on slow depolarizing humps) from hyperpolarized potentials. Both these physiological types corresponded to a range of morphologies: (i) somatostatin-containing Martinotti cells with ascending axonal arbors to layer I (some were also positive for calbindin D28k); (ii) VIP-containing double bouquet cells with descending axonal arbors as well as arcade cells (these included small cells immunoreactive for CCK or calretinin). Each subtype of cells made GABAergic synapses onto relatively specific portions of cortical cells, but similar domains were innervated by multiple classes of GABA cells.