Biomaterial Database

Influence of presynaptic receptors on neuromuscular transmission in rat. 1982

D F Wilson

The presence and physiological significance of acetylcholine (ACh) receptors on motor nerve terminals was examined at the rat diaphragm neuromuscular junction. Intracellular recording techniques were used to monitor end-plate potentials (EPP), miniature end-plate potentials (MEPP), and resting potentials of the muscle fibers. Muscle action potentials were blocked by the cut-muscle technique. Quantal release was determined by the ratio EPP/MEPP, after correcting for nonlinear summation. Blockade of acetylcholinesterase with eserine and neostigmine was tested to determine the influence of residual ACh on transmitter release. Partial blockade of ACh receptors with curare was examined to further clarify the role of these presynaptic receptors. The experiments demonstrate that residual ACh inhibits transmitter release and that blockade of ACh receptors enhances transmitter release. It is concluded that presynaptic ACh receptors exist and that they serve an important physiological function. It is suggested that the presynaptic ACh receptors normally serve to limit transmitter release in a negative feedback pathway.

UI	MeSH Term	Description	Entries
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009045	Motor Endplate	The specialized postsynaptic region of a muscle cell. The motor endplate is immediately across the synaptic cleft from the presynaptic axon terminal. Among its anatomical specializations are junctional folds which harbor a high density of cholinergic receptors.	Motor End-Plate,End-Plate, Motor,End-Plates, Motor,Endplate, Motor,Endplates, Motor,Motor End Plate,Motor End-Plates,Motor Endplates
D009388	Neostigmine	A cholinesterase inhibitor used in the treatment of myasthenia gravis and to reverse the effects of muscle relaxants such as gallamine and tubocurarine. Neostigmine, unlike PHYSOSTIGMINE, does not cross the blood-brain barrier.	Synstigmin,Neostigmine Bromide,Neostigmine Methylsulfate,Polstigmine,Proserine,Prostigmin,Prostigmine,Prozerin,Syntostigmine,Bromide, Neostigmine,Methylsulfate, Neostigmine
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D009469	Neuromuscular Junction	The synapse between a neuron and a muscle.	Myoneural Junction,Nerve-Muscle Preparation,Junction, Myoneural,Junction, Neuromuscular,Junctions, Myoneural,Junctions, Neuromuscular,Myoneural Junctions,Nerve Muscle Preparation,Nerve-Muscle Preparations,Neuromuscular Junctions,Preparation, Nerve-Muscle,Preparations, Nerve-Muscle
D010830	Physostigmine	A cholinesterase inhibitor that is rapidly absorbed through membranes. It can be applied topically to the conjunctiva. It also can cross the blood-brain barrier and is used when central nervous system effects are desired, as in the treatment of severe anticholinergic toxicity.	Eserine
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014403	Tubocurarine	A neuromuscular blocker and active ingredient in CURARE; plant based alkaloid of Menispermaceae.	Tubocurare,Tubocurarine Chloride,d-Tubocurare,d-Tubocurarine