SINGLE-CHANNEL CURRENTS FROM ZONA-FREE MOUSE EGGS

Single-channel patch-clamp techniques were used to identify and characterize a Ca2+-activated nonspecific cation channel (CAN channel) on insect olfactory receptor neurones (ORNs) from antennae of male Antheraea polyphemus. The CAN channel was found both in acutely isolated ORNs from developing pupae and in membrane vesicles from mature ORNs that presumably originated from inner dendritic segments. Amplitude histograms of the CAN single-channel currents presented well-defined peaks corresponding to at least four channel substates each having a conductance of about 16 pS. Simultaneous gating of the substates was achieved by intracellular Ca2+ with an EC50 value of about 80 nmoll−1. Activity of the CAN channel could be blocked by application of amiloride (IC50 <100nmoll−1). Moreover, in the presence of 1μmoll−1 Ca2+, opening of the CAN channel was totally suppressed by 10 μmoll−1 cyclic GMP, whereas ATP (1 mmol l−1) was without effect. We suggest that the CAN channel plays a specific role in modulation of cell excitability and in shaping the voltage response of ORNs.

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Ionic Mechanisms and Selectivity of the Gramicidin Transmembrane Channel: Cation Nuclear Magnetic Resonance, Dielectric Relaxation, Carbon-13 Nuclear Magnetic Resonance, and Rate Theory Calculation of Single Channel Currents

Spectroscopy of Biological Molecules ◽

10.1007/978-94-009-6490-7_25 ◽

1984 ◽

pp. 511-538 ◽

Cited By ~ 3

Author(s):

Dan W. Urry

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Single Channel ◽

Rate Theory ◽

Transmembrane Channel ◽

Ionic Mechanisms ◽

Single Channel Currents ◽

Theory Calculation ◽

Channel Currents ◽

Nuclear Magnetic

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Voltage-clamp studies in axons: Macroscopic and single-channel currents

The Axon ◽

10.1093/acprof:oso/9780195082937.003.0013 ◽

1995 ◽

pp. 257-280 ◽

Cited By ~ 31

Author(s):

WERNER VOGEL ◽

JÜRGEN R. SCHWARZ

Keyword(s):

Voltage Clamp ◽

Single Channel ◽

Single Channel Currents ◽

Channel Currents

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SINGLE CHANNEL CURRENTS IN RETINAL CELLS

Noise in Physical Systems and 1/f Noise 1985 ◽

10.1016/b978-0-444-86992-0.50044-8 ◽

1986 ◽

pp. 209-212

Author(s):

Davide LOVISOLO ◽

Renzo LEVI ◽

Dario CANTINO ◽

Elena STROBBIA

Keyword(s):

Single Channel ◽

Retinal Cells ◽

Single Channel Currents ◽

Channel Currents

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Nonselective cation and Cl channels in luminal membrane of the marginal cell

AJP Cell Physiology ◽

10.1152/ajpcell.1993.265.1.c72 ◽

1993 ◽

Vol 265 (1) ◽

pp. C72-C78 ◽

Cited By ~ 34

Author(s):

H. Sunose ◽

K. Ikeda ◽

Y. Saito ◽

A. Nishiyama ◽

T. Takasaka

Keyword(s):

Single Channel ◽

Patch Clamp Technique ◽

Cl Channel ◽

Luminal Membrane ◽

Cl Channels ◽

Cytoplasmic Acidification ◽

Marginal Cells ◽

Single Channel Currents ◽

Channel Currents ◽

Linear Conductance

Single-channel currents of the luminal membrane of marginal cells dissected from the guinea pig cochlea were investigated using the patch-clamp technique. Nonselective cation channels having a linear conductance of 27 pS were activated by depolarization, cytoplasmic Ca2+, and cytoplasmic acidification. Cytoplasmic ATP inactivated the channel. A mixture of 3-isobutyl-1-methylxanthine and forskolin activated a small-conductance Cl channel in the cell-attached mode. On excision in the inside-out mode, the Cl channel was inactivated, but it was reactivated by a cytoplasmic catalytic subunit of protein kinase A with ATP. This Cl channel had a linear conductance of 12 pS, and its activity was little affected by voltage. The sequence of permeation by anions was Br- > Cl > I-. The Cl channel blocker diphenylamine-2-carboxylic acid (3 mM) completely blocked the channel, but 5-nitro-2-(3-phenylpropylamino)-benzoic acid (50 microM) blocked it only partially. The above-mentioned characteristics are similar to those of the well-demonstrated Cl- channel, cystic fibrosis transmembrane regulator.

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