Single-channel currents recorded from membrane of denervated frog muscle fibres

  title={Single-channel currents recorded from membrane of denervated frog muscle fibres},
  author={Erwin Neher and Bert J. Sakmann},
THE ionic channel associated with the acetylcholine (ACh) receptor at the neuromuscular junction of skeletal muscle fibres is probably the best described channel in biological membranes. Nevertheless, the properties of individual channels are still unknown, as previous studies were concerned with average population properties. Macroscopic conductance fluctuations occurring in the presence of ACh were analysed to provide estimates for single channel conductance and mean open times1–3. The values… Expand
Acetylcholine activates single sodium channels in smooth muscle cells
From features of the macroscopic and single channel currents, it is concluded that these muscarinic ACh(CCh)-activated channels mainly pass Na ion and play a major part in the membrane depolarization produced by ACh or CCh in mammalian intestinal smooth muscles. Expand
Single postsynaptic channel currents in tissue cultured muscle
Measurements of single-channel currents induced by the agonist carbamylcholine in tissue-cultured mammalian muscle confirm the earlier noise studies on tissue culture preparations. Expand
Developmental changes in acetylcholine receptor channel properties of vertebrate skeletal muscle.
In 1972 Katz and Miledi reported by analyzing the acetylcholine (ACh)-induced voltage noise in frog skeletal muscle that the elementary voltage changes were greater in denervated muscle than in innervated Muscle, the first indication that two types of channels exist in adult frog muscle following denervation. Expand
Single channel properties of newly synthesized acetylcholine receptors following denervation of mammalian skeletal muscle
These data argue against the proposal that, in denervated muscle, the low- conductance channels undergo continued conversion to the high-conductance type focally at the site of former synaptic contact and provide additional support for the idea that the functional properties of ACh receptors are governed uniformly by the state of innervation of the fiber. Expand
Fluctuations in the microsecond time range of the current through single acetylcholine receptor ion channels
Results obtained with the acetylcholine-like agonist, suberyldicholine, suggest that the brief gaps do not result from ion channel block by the agonist itself, but which are consistent with a mechanism in which the channel opens and closes several times during a single agonist receptor occupancy. Expand
Discrete Current Fluctuations Produced by Single K+-Channels in the Squid Axon Membrane
Ionic currents in the electrically excitable membrane of nerves are composed of contributions from many independent ion-channels. Fluctuation analysis has shown that each channel contributesExpand
Properties of single potassium channels in vesicles formed from the sarcolemma of frog skeletal muscle.
The patch‐clamp method was used to study unitary delayed rectifier K+ channels in large vesicles formed from the membrane of frog skeletal muscle, and results imply a scheme with at least three closed states, an open and an inactivated state. Expand
Single-channel currents in isolated patches of plasma membrane from basal surface of pancreatic acini
Measurements of single-channel currents from isolated patches of plasma membrane (inside-out) from the baso-lateral surface of collagenase-isolated rat and mouse pancreatic acini identify a cation channel having a conductance of ∼30 pS and a mean open time in the range 0.3–1 s which is dependent on internal calcium. Expand
Multiple conductance states of single acetylcholine receptor channels in embryonic muscle cells
It is concluded that AChR channels in embryonic muscle adopt, in addition to a ‘main’ conductance state, a ’substate’ of lower conductance. Expand
The units of calcium conduction in Helix neurones
The suction pipette technique is used, which combines methods of internal perfusion and voltage clamp, to study ICa in isolated nerve cell bodies of the snail, Helix aspersa, and finds γCa to be less than 1 pS however, and it is suggested that the low value results from the effect of a Ca2+ binding site in the conductance. Expand


Relaxation spectra of potassium channel noise from squid axon membranes.
  • H. M. Fishman
  • Chemistry, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1973
By comparison of the values of f(c) from relaxation spectra of membrane channel noise with those from calculated (Hodgkin-Huxley equations) power spectra, it is possible to relate and compare channel models that previously could only be applied to macroscopic potassium conductance data. Expand
Conductance of channels opened by acetylcholine-like drugs in muscle end-plate
This work has estimated average single channel conductances for four cholinomimetic agonists, and finds this prediction that a channel, once it is open, will have the same conductance whichever drug caused it to open is not confirmed. Expand
Discreteness of Conductance Change in Bimolecular Lipid Membranes in the Presence of Certain Antibiotics
NET ion movements across biological or synthetic lipid membranes may take place by various mechanisms, underlying all of which there is a rather ill-defined and small ion leakage or backgroundExpand
Impedance of a Small Electrically Isolated Area of the Muscle Cell Surface
  • A. Strickholm
  • Materials Science, Medicine
  • The Journal of general physiology
  • 1961
The frequency dependence of the muscle cell membrane capacity found earlier by other methods has been confirmed and the internal phase angle of the complex impedance plot of whole muscle probably does not result from a distribution of fiber diameters and membrane capacities. Expand
Active phase of frog's end-plate potential.
The purpose of the present experiment was to determine directly the time course of the active phase of the e. Expand
Voltage clamp analysis of acetylcholine produced end‐plate current fluctuations at frog neuromuscular junction
1. Acetylcholine produced end‐plate current (e.p.c.) noise is shown to be the results of statistical fluctuations in the ionic conductance of voltage clamped end‐plates of Rana pipiens.
The characteristics of ‘end‐plate noise’ produced by different depolarizing drugs
1. End‐plate depolarization and associated ‘membrane noise’ due to decamethonium, acetylthiocholine and suberyldicholine have been examined and compared with the effects of acetylcholine andExpand
The statistical nature of the acetylcholine potential and its molecular components
1. When a steady dose of acetylcholine is applied to an end‐plate, the resulting depolarization is accompanied by a significant increase in voltage noise, and this noise can be significant in both the positive and the negative directions. Expand
Effects of proteolytic enzymes on function and structure of frog neuromuscular junctions
1. Frog cutaneous pectoris nerve‐muscle preparations were incubated with collagenase and protease and examined with electrophysiological and electron microscopic techniques.