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A neuromuscular junction (or myoneural junction) is a chemical synapse between a motor neuron and a muscle fiber. [1] It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. [2] Muscles require innervation to function—and even just to maintain muscle tone, avoiding atrophy.
The possibility of transient fusion and rapid retrieval of vesicle membrane was proposed by Bruno Ceccarelli in 1973, after examining in the electron microscope strongly stimulated frog neuromuscular junctions, and indirectly supported by the work of his group in the following years, using electrophysiology, electron microscopy and quick ...
By studying denervation in frog skeletal muscle, it was discovered that glial cells, particularly Schwann cells, behave as neurotrophic factors by taking on neuronal activity and releasing Acetylcholine themselves in order to preserve the neuromuscular junction. [6]
Whittaker's work demonstrating acetylcholine in vesicle fractions from guinea-pig brain was first published in abstract form in 1960 and then in more detail in 1963 and 1964, [36] [37] and the paper of the de Robertis group demonstrating an enrichment of bound acetylcholine in synaptic vesicle fractions from rat brain appeared in 1963. [38]
Neuromuscular junction (NMJ), a cholinergic synapse in vertebrates, glutamatergic in insects; Ciliary calyx in the ciliary ganglion of chicks [40] Calyx of Held in the brainstem; Ribbon synapse in the retina; Schaffer collateral synapses in the hippocampus. These synapses are small, but their pre- and postsynaptic neurons are well separated ...
During the 1950s, Bernard Katz and Paul Fatt observed spontaneous miniature synaptic currents at the frog neuromuscular junction. [33] Based on these observations, they developed the 'quantal hypothesis' that is the basis for our current understanding of neurotransmitter release as exocytosis and for which Katz received the Nobel Prize in ...
The interface between a motor neuron and muscle fiber is a specialized synapse called the neuromuscular junction. Upon adequate stimulation, the motor neuron releases a flood of acetylcholine (Ach) neurotransmitters from synaptic vesicles bound to the plasma membrane of the axon terminals.
Glutamate released from the upper motor neurons triggers depolarization in the lower motor neurons in the anterior grey column, which in turn causes an action potential to propagate the length of the axon to the neuromuscular junction where acetylcholine is released to carry the signal across the synaptic cleft to the postsynaptic receptors of the muscle cell membrane, signaling the muscle to ...