Electrophysiology




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Electrophysiology

Selected electrophysiological measurements

Synaptically evoked EPSP recorded from hypoglossal motoneuron in a brainstem slice preparation from the neonatal rat brain. Essin_K_EurJNeurosci_2002.pdf, Fig.5.

Effect of IEM-1925, a selective channel blocker of calcium-permeable AMPA receptors, on hypoglossal motoneuron EPSP.
(A) Synaptically evoked currents in control solution and in the presence of 50 mM IEM-1925.
(B) Time course of changes in amplitude of EPSCs following application of IEM-1925 (50 mM) and drug washout.

Proton-evoked currents through acid-sensing ion channels (ASICs) in freshly isolated hippocampal interneuron and hypoglossal motoneuron evoked by fast application of acidic extracellular solutions. Bolshakov_KV_Neuroscience_2002.pdf, Fig.2.

Sensitivity of hypoglossal motoneuron and hippocampal interneuron to pH drops.

(A) Representative responses of hypoglossal motoneuron (left) and hippocampal interneuron (right).

(B) Concentration dependence of peak amplitude for the same hypoglossal motoneuron (filled squares) and hippocampal interneuron (open squares).

Spontaneous transient outward currents (STOCs) and calcium sparks in mouse cerebral artery myocytes in BK channel knockout mice. Sausbier_M_Circulation_2005.pdf, Fig.4.

Lack of STOCs but presence of normal Ca2+ sparks in BK-/- cerebral artery smooth muscle cells.

a, STOC activity in WT and BK-/- cerebral arterial cells recorded at increasing membrane potentials
and STOC frequency at -20 mV.

b, Confocal line scans of fluo 3–loaded WT and BK-/- cells and time course of corresponding Ca2+ sparks. Spark amplitudes were measured as local fractional fluorescence increases (F/F0; F0 is baseline). Spark duration was measured at half-maximal amplitude.

Proton currents in human blood and mouse bone-marrow neutrophils. Essin_K_AJP_2007.pdf, Fig.5.

Proton-like currents in human and mouse neutrophils were not sensitive to iberiotoxin but were blocked by Zn2+. Currents in human and BK-/- and BK+/+ mouse neutrophils were recorded in the absence and presence of 1 µg/ml PMA (5–7 min after stimulation), in the presence of 1 µg/ml PMA + 100 nM iberiotoxin (10–15 min after application), and in the presence of 1 µg/ml PMA and 3 mM ZnCl2 (1–3 min after application). Amphotericin-perforated cells were voltage clamped at a holding potential of -60 mV and pulsed for 8 s from -60 to +60 mV in 20-mV increments every 20 s. Recordings were performed in symmetrical high-K+ aspartate solutions supplemented with NH4.

Single channel activity of TRPC6 heterologically expressed in HEK293. Leuner_K_FASEB_2007.pdf, Fig 6.

Hyperforin-induced TRPC6 single channel activity is blocked by gadolinium ions. A) Top panels: currents recorded
in outside-out patches from TRPC6-expressing cell at the holding potential of –60 mV before (left trace) and after application
of 10 µM hyperforin (middle trace) and 100 µMGd3+ (right trace) to the bath solution. Bottom panels: amplitude distributions
of detected channel openings shown on the top and calculated from current traces of 50 s length. B) Left: single channel
amplitudes in control (white), after application of 10 µM hyperforin (black) and after 100 µM Gd3+ in the presence of 10 µM
hyperforin (gray; n=5). Right: NPo in control (white), after application of 10 µM hyperforin (black), and after 100 µM Gd3+
(gray) (n=5).

Electrophysiological recordings and calcium measurements in C.elegans pharynx. Optogenetic control (ChR2) of the pharynx pumping rate.

A. Extrapharyngeal recording (EPG). An example of extracellular recording of action potential from a wild-type (N2) pharynx. The peaks detected reflect: e – corpus contraction, E – terminal bulb contraction; P – M3 „Inhibitory potentials"; R – corpus relaxation, r – terminal bulb relaxation.
B. Intracellular recording of action potential from the terminal bulb of a wild-type (N2) pharynx. High resistance (50 MOm, alumosilicate) sharp microelectrode was used.
C. Simultenious measurement of calcium waves (genetically encoded calcium indicator GCaMP3) and action potentials (extracellular recording) in C.elegans pharynx. The calcium increases detected in pharyngeal muscles (the graph above) are associated with the trains of action potentials (the bottom graph).
D. Optogenetic control of the pharynx pumping rate in a C.elegans worm which expressed ChR2 under myo-2 (a pharynx specific promotor). In an initially silent pharynx (control), millisecond 470 nm light pulses of different frequenses (0.25, 0.5, 1, 2 and 4 Hz) evoked pharyngeal contractions and action potentials. Action potentials were detected by extracellular recordings (EPG).

Voltage dependent calcium channel (VDCC) currents in mouse oocyte.

Voltage dependent calcium channel (VDCC) currents in mouse oocyte in control and in the presence of 10 mM strontium, a parthenogenetic activator of eggs. Currents were elicited by 100 ms test potentials from -100 to +100 mV. Holding potential was set at -80 mV.

Kirill Esin, essine_kv@yahoo.com