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Acetylcholine (Ach) is a chemical that serves as a neurotransmitter, communicating nerve impulses between the cells of the nervous system. It is largely associated with the transmission of impulses across the synapse between nerve and muscle cells, causing the muscles to contract. ACh is produced in the synaptic knob and stored in vesicles until a nerve impulse triggers its discharge across the synapse. When the ACh reaches the membrane of the receiving cell it binds with a specific site and brings about depolarisation - a reversal of the electric charge on either side of the membrane causing a fresh impulse in nerve cells or a contraction in muscle cells. Its action is short-lived because it is quickly destroyed by the enzyme cholinesterase. Anticholinergic drugs have a number of uses in medicine to block the action of ACh, thereby disrupting the passage of nerve impulses and relaxing certain muscles, for example in premedication before surgery.
 Research Acetylcholine
A monoamine is a biogenic amine neurotransmitter with a single amino group.
Research Monoamine
The nerve-muscle junction features a connection, or synapse, between an axon terminal and a group of muscle fibres. A space between the neural and muscular tissue is called the synaptic space. When a nerve impulse is transmitted to the axon terminal, it causes a neurotransmitter to be released from small sacs, called synaptic vesicles, within the terminal, or knob. The neurotransmitter causes sodium ions to be transferred to the muscle fibres which, in turn, contract. The neurons are covered by an insulating, lipid-based coating, called the myelin sheath, which prevents stray neural signals from passing to other neurons or to other tissues.
Research Nerve-Muscle Interface
A neurotransmitter is a chemical by which a nerve cell communicates with another nerve cell or with a muscle.
Research Neurotransmitter
Pagodone is a drug which mimics the action of GABA, a neurotransmitter, which reduces excessive neuronal activity thought to be responsible for the symptoms of anxiety and panic attacks.
Research Pagodone
Serotonin or 5-hydroxytryptamine (5-HT) is a compound widely distributed in human tissue, particularly in the blood, wall of the intestine and the central nervous system. It acts as a neurotransmitter concerned especially with the process of sleep.
Research Serotonin
The synapse is a specialized region where one nerve signal jumps form one nerve cell to another. It is the site of communication between two nerve cells. A tiny gap, called the synaptic gap, extists between cells. A nerve impulse must pass through the synaptic gap via the release of transmitter substances to be transmitted from one nerve cell to another. At the tip of the axon are tiny secretory cups, or vesicles, which produce a trace of a chemical substance known as a neurotransmitter when the electrical impulses reach them. Neurotransmitters then diffuse across the synapse and excite the dendrites of the next cell to induce a new electrical impulse in their cell. The process continues down the chain. Nerve impulses flow only in one direction and are subject to fatigue, oxygen deficiency, anesthetics and other chemical agents.
Research Synapse
Glutamic acid or glutaminic acid is a nonessential amino acid, occurring in proteins, that acts as a neurotransmitter and plays an important part in nitrogen metabolism.
Research Glutamic Acid
Glycine (Aminoethanoic acid) is a simple (the simplest) non-essential amino acid occurring in most proteins, that acts as a neurotransmitter.
Research Glycine
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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