Biomaterial Database

Depression of spinal monosynaptic transmission by diethyl ether: quantal analysis of unitary synaptic potentials. 1978

E Zorychta, and R Capek

The site at which diethyl ether impairs transmission in the spinal monosynaptic pathway was studied by intracellular recording from lumbosacral motoneurons. The drug was administered by inhalation to spinal cats, in concentrations which produce surgical anesthesia. Ether had no significant effect on resting potential or input resistance of the cell membrane. It decreased the electrical excitability in some but not all motoneurons. This action may contribute to the depressant effects of ether. Monosynaptic excitatory postsynaptic potentials evoked by impulses in a single Ia afferent fiber (unitary EPSPs) of the triceps surae nerve were recorded from homonymous motoneurons. They were measured and their amplitude distribution was analyzed by a computer-aided procedure. The mean amplitude of the unitary EPSPs was 0.15 to 0.31 mV, and the mean number of transmitter quanta released by each impulse ranged from 1.5 to 4.1 before drug administration. Both values were decreased during inhalation of ether but recovered toward normal after the drug was discontinued. The mean amplitude of the EPSPs produced by one transmitter quantum was 0.08 to 0.15 mV and was not depressed during ether administration. It is concluded that either in anesthetic concentrations depresses synaptic potentials presynaptically by decreasing the amount of excitatory transmitter released, while leaving the chemosensitivity of the postsynaptic membrane unchanged.

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
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
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
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D004986	Ether	A mobile, very volatile, highly flammable liquid used as an inhalation anesthetic and as a solvent for waxes, fats, oils, perfumes, alkaloids, and gums. It is mildly irritating to skin and mucous membranes.	Diethyl Ether,Ether, Ethyl,Ethyl Ether,Ether, Diethyl
D005019	Ethyl Ethers	Organic compounds having ethyl groups bound to an oxygen atom.	Ethoxy Compounds,Compounds, Ethoxy,Ethers, Ethyl
D005260	Female		Females
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential