Biomaterial Database

Cholinergic neuromuscular synapses in Aplysia have low endogenous acetylcholinesterase activity and a high-affinity uptake system for acetylcholine. 1994

P E Lloyd, and P J Church

Department of Pharmacological and Physiological Sciences, University of Chicago, Illinois 60637.

In the present study, we have demonstrated that ACh is the predominant fast excitatory transmitter used by identified motor neurons innervating feeding muscles in Aplysia. A detailed study of ACh metabolism was then carried out in a well-characterized neuromuscular preparation, intrinsic muscle 5 (15). This neuromuscular system has a high-affinity uptake system for choline. The rate of uptake of choline was increased by motor neuron stimulation, and this increased uptake appears to be selectively targeted to motor neuron terminals. These properties appear similar to those observed in vertebrate neuromuscular preparations. However, we have made two observations that are surprising in light of our knowledge concerning the vertebrate neuromuscular junction where released ACh is rapidly hydrolyzed by acetylcholinesterase (AChE) to choline, which is then taken up by a high-affinity uptake system. This Aplysia neuromuscular system has limited endogenous AChE activity and contains a separate high-affinity uptake system for ACh itself that actually has a higher velocity than that for choline uptake. It is possible that the uptake system for ACh is involved in terminating the action of released transmitter in a manner similar to that previously described for noncholinergic transmitters. Using this preparation, we have demonstrated release of labeled ACh in response to intracellular stimulation of identified motor neurons. The release per spike appears to be highly plastic,increasing markedly with stimulation frequency. This preparation is amendable to study the regulation of release of peptide and conventional transmitters from the terminals of individual neurons.

UI	MeSH Term	Description	Entries
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009412	Nerve Fibers	Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.	Cerebellar Mossy Fibers,Mossy Fibers, Cerebellar,Cerebellar Mossy Fiber,Mossy Fiber, Cerebellar,Nerve Fiber
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
D010275	Parasympathetic Nervous System	The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.	Nervous System, Parasympathetic,Nervous Systems, Parasympathetic,Parasympathetic Nervous Systems,System, Parasympathetic Nervous,Systems, Parasympathetic Nervous
D002610	Cheek	The part of the face that is below the eye and to the side of the nose and mouth.	Bucca,Buccas,Cheeks
D002794	Choline	A basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism.	Bursine,Fagine,Vidine,2-Hydroxy-N,N,N-trimethylethanaminium,Choline Bitartrate,Choline Chloride,Choline Citrate,Choline Hydroxide,Choline O-Sulfate,Bitartrate, Choline,Chloride, Choline,Choline O Sulfate,Citrate, Choline,Hydroxide, Choline,O-Sulfate, Choline
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D000109	Acetylcholine	A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.	2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine
D000110	Acetylcholinesterase	An enzyme that catalyzes the hydrolysis of ACETYLCHOLINE to CHOLINE and acetate. In the CNS, this enzyme plays a role in the function of peripheral neuromuscular junctions. EC 3.1.1.7.	Acetylcholine Hydrolase,Acetylthiocholinesterase,Hydrolase, Acetylcholine