Single channel currents activated by glycine and GABA in spinal cord neurons

1981 ◽  
Vol 7 (4) ◽  
pp. 290-290 ◽  
Author(s):  
J. Bormann
Keyword(s):  
Spinal Cord ◽  
Single Channel ◽  
Spinal Cord Neurons ◽  
Single Channel Currents ◽  
Channel Currents

Spontaneous and GABA-induced single channel currents in cultured murine spinal cord neurons

1985 ◽  
Vol 63 (10) ◽  
pp. 1228-1233 ◽  
Author(s):  
David A. Mathers
Keyword(s):  
Spinal Cord ◽  
Time Constant ◽  
Single Channel ◽  
Resting Potential ◽  
Embryonic Mouse ◽  
Spinal Cord Neurons ◽  
Frequency Distributions ◽  
Exponential Term ◽  
Single Channel Currents ◽  
Channel Currents

Intracellular and patch clamp recordings were made from embryonic mouse spinal cord neurons growing in primary cell culture. Outside-out membrane patches obtained from these cells usually showed spontaneous single channel currents when studied at the resting potential (−56 ± 1.5 mV). In 18 out of 30 patches tested, spontaneous single channel activity was abolished by making Tris+ the major cation on both sides of the membrane. The remaining patches continued to display spontaneous single channel currents under these conditions. These events reversed polarity at a patch potential of 0 mV and displayed a mean single channel conductance of 24 ± 1.2 pS. Application of the putative inhibitory transmitter γ-aminobutyric acid (0.5–10 μM) to outside-out patches of spinal cord cell membrane induced single channel currents in 10 out of 15 patches tested. These channels had a primary conductance of 29 ± 2.8 pS in symmetrical 145 mM Cl solutions. Frequency distributions for the open times of these channels were well fit by the sum of a fast exponential term ("of") with a time constant τof = 4 ± 1.3 ms and a slow exponential term ("os") with a time constant τos = 24 ± 8.1 ms. Frequency distributions for channel closed times were also well fit by a double exponential equation, with time constants τcf = 2 ± 0.2 ms and τcs = 62 ± 20.9 ms.

A Calcium-Activated Nonspecific Cation Channel from Olfactory Receptor Neurones of the Silkmoth Antheraea Polyphemus

1991 ◽  
Vol 161 (1) ◽  
pp. 455-468
Author(s):  
F. ZUFALL ◽  
H. HATT ◽  
T. A. KEIL
Keyword(s):  
Olfactory Receptor ◽  
Single Channel ◽  
Membrane Vesicles ◽  
Cation Channel ◽  
Voltage Response ◽  
Antheraea Polyphemus ◽  
Cell Excitability ◽  
Olfactory Receptor Neurones ◽  
Single Channel Currents ◽  
Channel Currents

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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