Biomaterial Database

Sural nerve effects on medial gastrocnemius motoneurones in the cat. 1979

J G Colebatch, and J D Gillies

1. Excitability cycles for medial gastrocnemius motoneurones were recorded following sural nerve stimuli with amplitudes of 1.5, 3, 5, 10 and 40 times the nerve threshold. The monosynaptic reflex was time-integrated to quantify the motoneuronal output and some implications of this technique are discussed. In particular it is calculated that this method specifically examines the 15-25% most excitable motoneurones of the medial gastrocnemius pool.2. In most cases high amplitude stimulation of the sural nerve caused a triphasic (excitatory-inhibitory-excitatory) change in excitability. Arguments are given to support the conclusion that this represents a corresponding post-synaptic alteration in medial gastrocnemius motoneurone potential. It is concluded that this pattern illustrates the nature of the sural nerve projections to this portion of the medial gastrocnemius pool.3. The first period of excitation began after a latency, corrected to be compatible with intracellular recordings, of 2.8 ms and had a mean duration of 4.0 ms. The minimum stimulus level necessary for this effect lay between 1.5 and 3 times the nerve threshold. The maximum amplitude of this facilitation occurred with stimuli of 3-5 times threshold and was 60-90% of the amplitude of the monosynaptic facilitation which followed stimulation of the lateral gastrocnemius-soleus nerve.4. A period of inhibition followed immediately after the period of excitation and had a mean duration of 16 ms. The minimum stimulus level necessary for this effect lay between 1.5 and 3 times the nerve threshold and the degree of inhibition increased with stimuli up to 40 times threshold.5. The second period of excitation lasted a mean period of 50 ms and was due to activity in high threshold fibres. On average its amplitude was 50% that of the initial excitation.6. Exceptions to this triphasic variation of excitability were found. This result is interpreted as indicating the presence of projections with opposing actions which were simultaneously activated by sural stimuli.

UI	MeSH Term	Description	Entries
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
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
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
D009433	Neural Inhibition	The function of opposing or restraining the excitation of neurons or their target excitable cells.	Inhibition, Neural
D012023	Reflex, Monosynaptic	A reflex in which the AFFERENT NEURONS synapse directly on the EFFERENT NEURONS, without any INTERCALATED NEURONS. (Lockard, Desk Reference for Neuroscience, 2nd ed.)	Monosynaptic Reflex
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
D005071	Evoked Potentials	Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.	Event Related Potential,Event-Related Potentials,Evoked Potential,N100 Evoked Potential,P50 Evoked Potential,N1 Wave,N100 Evoked Potentials,N2 Wave,N200 Evoked Potentials,N3 Wave,N300 Evoked Potentials,N4 Wave,N400 Evoked Potentials,P2 Wave,P200 Evoked Potentials,P50 Evoked Potentials,P50 Wave,P600 Evoked Potentials,Potentials, Event-Related,Event Related Potentials,Event-Related Potential,Evoked Potential, N100,Evoked Potential, N200,Evoked Potential, N300,Evoked Potential, N400,Evoked Potential, P200,Evoked Potential, P50,Evoked Potential, P600,Evoked Potentials, N100,Evoked Potentials, N200,Evoked Potentials, N300,Evoked Potentials, N400,Evoked Potentials, P200,Evoked Potentials, P50,Evoked Potentials, P600,N1 Waves,N2 Waves,N200 Evoked Potential,N3 Waves,N300 Evoked Potential,N4 Waves,N400 Evoked Potential,P2 Waves,P200 Evoked Potential,P50 Waves,P600 Evoked Potential,Potential, Event Related,Potential, Event-Related,Potential, Evoked,Potentials, Event Related,Potentials, Evoked,Potentials, N400 Evoked,Related Potential, Event,Related Potentials, Event,Wave, N1,Wave, N2,Wave, N3,Wave, N4,Wave, P2,Wave, P50,Waves, N1,Waves, N2,Waves, N3,Waves, N4,Waves, P2,Waves, P50
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
D013127	Spinal Nerves	The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included.	Nerve, Spinal,Nerves, Spinal,Spinal Nerve
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