Biomaterial Database

Electrophysiological properties of spinal motoneurones of normal and dystrophic mice. 1975

P Huizar, and M Kuno, and Y Miyata

1. The properties of spinal motoneurones of normal and dystrophic mice (129/ReJ) were examined with intracellular electrodes. 2. The following parameters of spinal motoneurones showed no significant differences between normal and dystrophic mice: resting and action potentials, the amplitude and duration of after-hyperpolarization, rheobasic current for excitation, threshold for excitation of the somadendritic membrane (IS-SD inflexion) and input resistance. 3. The changes in motoneurone properties observed 13-16 days after section of the sciatic nerve (axotomy) were similar in both normal and dystrophic mice. 4. The axonal conduction velocity of motoneurones in dystrophic mice was about ten times slower than that in normal mice. The conduction velocity of the sciatic nerve was only about 25% slower in dystrophic mice than in the normal animal. The estimated ventral root conduction velocity as well as the observed dorsal root conduction velocity in dystrophic mice was at least twenty times slower than that in normal mice. 5. In dystrophic mice, spinal motoneurones often showed multiple discharges in response to single, antidromic stimuli. The site of initiation of multiple discharge was located in the motor axon rather than in the motoneurone cell body. 6. In dystrophic mice, nerve impulses were transmitted from fibre to fibre ('cross-talk'). The site of impulse transmission among nerve fibres was near the distal portion of the spinal roots. 7. Synaptic potentials and peripheral reflex discharges evoked by stimulation of the dorsal roots showed a longer latency and were more prolonged in dystrophic mice than in the control mice. 8. The motoneurone properties of dystrophic mice showed no tendency of progressive changes with age ranging from 63 to 148 days. 9. It is concluded that the properties of motoneurone cell bodies examined in dystrophic mice are indistinguishable from those in normal mice and that the only abnormality in motoneurones of the former residues in the motor axon. 10. It is suggested that integrity of the discharge pattern of spinal motoneurones in dystrophic mice is interfered by anomalous impluse transmission in the motor axons and that the motoneurones in dystrophic mice are a homogeneous group rather than a mixture of "normal" and "abnormal" neurones.

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
D009137	Muscular Dystrophy, Animal	MUSCULAR DYSTROPHY that occurs in VERTEBRATE animals.	Animal Muscular Dystrophies,Animal Muscular Dystrophy,Dystrophies, Animal Muscular,Dystrophy, Animal Muscular,Muscular Dystrophies, Animal
D009431	Neural Conduction	The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.	Nerve Conduction,Conduction, Nerve,Conduction, Neural,Conductions, Nerve,Conductions, Neural,Nerve Conductions,Neural Conductions
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.
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
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