Biomaterial Database

Effect of tetanus toxin on the excitatory and the inhibitory post-synaptic potentials in the cat motoneurone. 1983

K Kanda, and K Takano

Tetanus toxin (100 mouse minimal lethal doses per kilogram) was injected into the medial gastrocnemius muscle of the cat. At various times thereafter, homonymous and heteronymous group Ia excitatory post-synaptic potentials (e.p.s.p.s), disynaptic reciprocal Ia inhibitory post-synaptic potentials (i.p.s.p.s) and post-synaptic potentials (p.s.p.s) produced by sural nerve stimulation were recorded in the medial gastrocnemius motoneurones. The duration of the after-hyperpolarization, the input resistance and the axonal conduction velocity of motoneurones were also measured. Homonymous Ia e.p.s.p.s remained normal until 72 h after toxin injection. However, 5 days after toxin injection, the amplitudes of Ia e.p.s.p.s. were significantly smaller than those in control animals (1.5 +/- 1.0 mV versus 5.6 +/- 2.7 mV; t test, P less than 0.001). Heteronymous Ia e.p.s.p.s produced by stimulation of the lateral gastrocnemius-soleus nerve 5 days after toxin injection were also significantly smaller than those in control animals (0.6 +/- 0.6 mV versus 2.5 +/- 1.5 mV; P less than 0.001). However, these heteronymous Ia e.p.s.p.s remained normal when the lateral gastrocnemius-soleus nerve was ligated and sectioned at the entry to those muscles just before the toxin injection. The ascending volleys, which are supposed to represent mainly the action potentials of the dorsal spinocerebellar tract and to be elicited monosynaptically by collaterals of group I afferents, were essentially the same in the left tetanic and right control sides up to 5 days after toxin injection. Ia i.p.s.p.s and the hyperpolarizing component of sural p.s.p.s could not be produced or were very small in motoneurones sampled later than 30 h after toxin injection. The duration of the after-hyperpolarization and the input resistance of motoneurones remained normal. Axonal conduction velocity of motoneurones measured 5 days after toxin injection was 89.4 +/- 12.7 m/s, and was significantly slower than that of control motoneurones (94.1 +/- 15.4 m/s) (P less than 0.005). Differences in the amplitude of group I incoming volleys between tetanic leg and contralateral control leg were not observed. These results suggest that tetanus toxin blocks excitatory synapses in the central nervous system as well as inhibitory synapses.

UI	MeSH Term	Description	Entries
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
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
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
D001369	Axons	Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.	Axon
D013497	Sural Nerve	A branch of the tibial nerve which supplies sensory innervation to parts of the lower leg and foot.	Nerve, Sural,Nerves, Sural,Sural Nerves
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
D013744	Tetanus Toxin	Protein synthesized by CLOSTRIDIUM TETANI as a single chain of ~150 kDa with 35% sequence identity to BOTULINUM TOXIN that is cleaved to a light and a heavy chain that are linked by a single disulfide bond. Tetanolysin is the hemolytic and tetanospasmin is the neurotoxic principle. The toxin causes disruption of the inhibitory mechanisms of the CNS, thus permitting uncontrolled nervous activity, leading to fatal CONVULSIONS.	Clostridial Neurotoxin,Clostridium tetani Toxin,Tetanus Toxins,Neurotoxin, Clostridial,Toxin, Clostridium tetani,Toxin, Tetanus,Toxins, Tetanus