Whole-cell current-recording

FIG. 5. SK currents in UBSM cells. (A) Original records of whole-cell currents recorded from a guinea-pig UBSM cell during a 100 ms depolarization from — 60 mV to +10 mV. Current is shown under baseline conditions (control), and after addition of the SK channel blocker apamin (100 nM). (B) The apamin-sensitive portion of the current in A is shown (SK current). Dotted lines indicated zero current. (From G.M. Herrera M.T. Nelson, unpublished observations.)... 

A small overlap in the voltage dependence of activation and inactivation leads to a persistent sodium current, also referred to as a window current. This current is very small compared to the peak current and may go unnoticed in typical whole cell current recordings. However, this current may play an important role in amplifying subthreshold depolarizations and thus in controlling excitability [7]. 

Hoyer J, Gogelein H (1991) Sodium-alanine cotransport in renal proximal tubule cells investigated by whole-cell current recording. J Gen Physiol 97 1073-1094 Merot J, Bidet M, Gachot B et al. (1988) Patch clamp study on primary culture of isolated proximal convoluted tubules. Pfliigers Arch. 413 51-61... 

Scott RH, Sweeney MI, Kobrinsky EM, Pearson HA, Timms GH, PuUar LA, Wedley S, Dolphin AC. Actions of arginine polyamine on voltage and hgand-activated whole cell currents recorded from cultured neurones. Br J Pharmacol 1992 106(l) 199-207. 

Figure 4. Whole-cell currents recorded from an axolotl vomeronasal receptor neuron in an epithelial slice. Currents were elicited by applying a series of voltage pulses, fiom -80 mV to +60 mV, in 10 mV increments. Vhoid = -80 mV. (A) Currents recorded in standard amphibian physiological saline, before any channel blockers were washed onto the slice. (B) Currents recorded 3 min after 10 pM tetrodotoxin (TTX) was washed onto the cell. TTX blocks voltage-gated sodium currents, revealing a second inward current. (C) Currents recorded 9 min after a solution containing both 10 pM TTX and 1 mM CoCk was washed onto the slice. Cobalt blocks calcium currents, demonstrating that the rapidly-inactivating inward current shown in panel B was carried by calcium.

Whole-cell and single-channel currents. Modern techniques permit the recording of neuronal currents in response to the application of transmitters and modulators of transmission. A Averaged and summed whole-cell currents evoked by the application of glutamate... 

In order to confirm the possible interaction of ethanol and crocin on NMDA receptors, we also performed whole-cell patch recording with primary cultured hippocampal neurons and measured membrane currents induced by the application of NMDA in a voltage-clamped condition. Application of 100 pM NMDA induced an inward current of 100.2 9.8 pA (n=10) at a holding potential of -60 mV. The NMDA-induced inward current was not affected by 10 pM CNQX (data not shown), but was completely abolished by 30 pM APV, supporting the fact that the response was mediated by NMDA receptors. Ethanol inhibited NMDA-induced currents in a concentration-dependent manner. Crocin (10 pM) had no effect on NMDA-induced currents by itself (data not shown), but attenuated the inhibitory effect of ethanol on NMDA-induced currents. The concentration-effect curve for ethanol was shifted to the right by the presence of crocin [22]. 

Fig. 10.1 Evidence for coupling between the A3 adenosine receptor and opening of the KATp channel in isolated mouse ventricular cardiomyocytes. (Panel a) Whole-cell current traces recorded...

The patch electrode voltage-clamp is the method of choice to study V, alterations (Hamill et al., 1981). However, the high resistance seals required for these studies are not readily formed on mammalian sperm due both to geometric factors as well as the low compliance of the plasma membrane (Arnoult et al., 1996b). To date, recordings of whole cell currents, as is essential for monitoring of V, have not been reported in sperm, despite the heroic efforts exerted to obtain excised patches from these cells (Espinosa et al., 1998). As an alternative, has been ex-... 

Whole-cell currents are usually obtained less than 3 minutes after seal formation. Series resistance is increased in most instances to range from 20 to 40 M 2. Occasionally, cells developed an increased leakage current during prolonged recording (>15 minutes Broadie and Bate 1993a), indicating that Nystatin had penetrated the cell, but this was usually not a problem. 

Figure 13.3 Whole-cell patch-clamp recordings of excitatory postsynaptic currents (EPSCs) from dorsal horn neurons of rat (prenatal P2-13) spinal cord slices. The normal evoked EPSC of about 160pA obtained by focal stimulation of nearby tissue was dramatically reduced by addition of a cocktail (CABS) of CNQX 10 pM, D-APV 50 pM, bicuculline 10 pM and strychnine 5 pM to block glutamate, GABAa and glycine receptors. The small residual EPSC shown was blocked by the ATP P2 receptor antagonist suramin and is therefore probably mediated by released ATP. (Prom Bardoni et al. 1997 and reproduced by permission of the Journal of Neuroscience)...

Whole-cell Voltage-Clamp Recordings of Na/K Pump Current Effects of Cellular Glutathione Manipulation... 

Hoffman, N. W., Wuarin, J. P. Dudek, F. E. (1994). Whole-cell recordings of spontaneous synaptic currents in medial preoptic neurons from rat hypothalamic shces mediation by amino acid neurotransmitters. Brain Res. 660, 349-52. 

The electrophysiological technique used to measure changes in membrane capacitance is the patch clamp [5,6] in the whole-cell recording mode, where the plasma membrane patch in the pipet is ruptured. In another configuration of the patch clamp, the plasma membrane patch is maintained intact. In this case, small currents due to the opening of individual channels can be measured in the membrane patch. The whole-cell patch clamp... 

Membrane currents were measured using conventional, whole-cell, tight seal recording. The composition of the extracellular solution was (mM) Na glutamate 80, NaCl 60, MgCl21.1, CaCl2 3, HEPES 10, and glucose 10 (pH 7.4 with NaOH). 

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