Biomaterial Database

On the origin of skewed distributions of spontaneous synaptic potentials in autonomic ganglia. 1998

M R Bennett, and L Farnell, and W G Gibson

Department of Physiology, University of Sydney, New South Wales, Australia.

The histograms of spontaneous synaptic potentials at synapses in autonomic ganglia are described by distributions consisting of mixtures of Gaussians, rather than by single Gaussian distributions. The possible origin of these mixed distributions is investigated, using Monte-Carlo simulations of the action of spontaneously released units of transmitter. A single unit of acetylcholine of fixed size, released from an active zone with receptor patches both beneath and adjacent to the zone, does not give rise to the observed histograms. But if the unit is of variable size, consisting of integer multiples of smaller units, and release is from an active zone onto either the receptor patch beneath, or in addition onto adjacent patches, then the histogram is well described by a mixture of Gaussians. However, this explanation is unlikely to be correct as present evidence suggests that in most cases the released unit of transmitter saturates the postsynaptic receptor patch beneath the active zone. The final case considered is where a unit of transmitter is spontaneously released from an active zone, simultaneously with a unit in an adjacent zone less than one micron away. The histogram of potentials then conforms to those observed even when there are differences in the sizes of the receptor patches. It is suggested that this kind of release could provide an explanation for distributions of spontaneous potentials that are mixtures of Gaussians.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D008962	Models, Theoretical	Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Experimental Model,Experimental Models,Mathematical Model,Model, Experimental,Models (Theoretical),Models, Experimental,Models, Theoretic,Theoretical Study,Mathematical Models,Model (Theoretical),Model, Mathematical,Model, Theoretical,Models, Mathematical,Studies, Theoretical,Study, Theoretical,Theoretical Model,Theoretical Models,Theoretical Studies
D009010	Monte Carlo Method	In statistics, a technique for numerically approximating the solution of a mathematical problem by studying the distribution of some random variable, often generated by a computer. The name alludes to the randomness characteristic of the games of chance played at the gambling casinos in Monte Carlo. (From Random House Unabridged Dictionary, 2d ed, 1993)	Method, Monte Carlo
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
D005725	Ganglia, Autonomic	Clusters of neurons and their processes in the autonomic nervous system. In the autonomic ganglia, the preganglionic fibers from the central nervous system synapse onto the neurons whose axons are the postganglionic fibers innervating target organs. The ganglia also contain intrinsic neurons and supporting cells and preganglionic fibers passing through to other ganglia.	Autonomic Ganglia,Ganglion, Autonomic,Autonomic Ganglion
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
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
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse
D017981	Receptors, Neurotransmitter	Cell surface receptors that bind signalling molecules released by neurons and convert these signals into intracellular changes influencing the behavior of cells. Neurotransmitter is used here in its most general sense, including not only messengers that act to regulate ion channels, but also those which act on second messenger systems and those which may act at a distance from their release sites. Included are receptors for neuromodulators, neuroregulators, neuromediators, and neurohumors, whether or not located at synapses.	Neurohumor Receptors,Neuromediator Receptors,Neuromodulator Receptors,Neuroregulator Receptors,Receptors, Neurohumor,Receptors, Synaptic,Synaptic Receptor,Synaptic Receptors,Neuromediator Receptor,Neuromodulator Receptor,Neuroregulator Receptor,Neurotransmitter Receptor,Receptors, Neuromediators,Receptors, Neuromodulators,Receptors, Neuroregulators,Receptors, Neurotransmitters,Neuromediators Receptors,Neuromodulators Receptors,Neuroregulators Receptors,Neurotransmitter Receptors,Neurotransmitters Receptors,Receptor, Neuromediator,Receptor, Neuromodulator,Receptor, Neuroregulator,Receptor, Neurotransmitter,Receptor, Synaptic,Receptors, Neuromediator,Receptors, Neuromodulator,Receptors, Neuroregulator