The response of alpha-motoneurons of different size to stretch and vibration of extensor muscles after injection of 5-hydroxytryptophan in spinal cats. 1976

P Wand

1. Vibration of the GS muscle at 100/sec, and the peak-to-peak amplitude of about 100 mu, produced slight reflex activity of homonymous and heteronymous alpha-motoneurons in the spinal, unanesthetized cat. 2. Intravenous injection of the 5-HT precursor 5-HTP (25 mg/kg, L-form) performed in the spinal preparation facilitated the responses of single extensor alpha-motoneurons to both vibration and stretch of the corresponding muscle. The 5-HT antagonist methysergide (0-5 mg/kg i. v.) blocked almost completely the facilitation of the vibration and stretch induced motoneuronal discharges produced by 5-HTP in the spinal cat, indicating that the facilitation was 5-HT specific. 4. A comparison of the types of alpha-motoneurons participating in the reflex responses elicited by the different stimuli in the spinal cat following injection of 5-HTP showed that both small-tonic and large-phasic alpha-motoneurons take part in both stretch and vibration reflexes. 5. It is concluded that the alpha-motoneuron pool of the GS muscle represents an homogenous population, no matter what kind of synaptic drive is used for its activation, and that the susceptibility of a motoneuron to discharge depends on the amount of the afferent excitatory input rather than on the modalities of sensory stimulation.

UI MeSH Term Description Entries
D008297 Male Males
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
D009119 Muscle Contraction A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments. Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009132 Muscles Contractile tissue that produces movement in animals. Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
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
D005260 Female Females
D006916 5-Hydroxytryptophan The immediate precursor in the biosynthesis of SEROTONIN from tryptophan. It is used as an antiepileptic and antidepressant. 5-HTP,Hydroxytryptophan,Oxitriptan,Oxytryptophan,Tryptophan, 5-Hydroxy-,5 Hydroxytryptophan,5-Hydroxy- Tryptophan,Tryptophan, 5 Hydroxy
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
D013116 Spinal Cord A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER. Coccygeal Cord,Conus Medullaris,Conus Terminalis,Lumbar Cord,Medulla Spinalis,Myelon,Sacral Cord,Thoracic Cord,Coccygeal Cords,Conus Medullari,Conus Terminali,Cord, Coccygeal,Cord, Lumbar,Cord, Sacral,Cord, Spinal,Cord, Thoracic,Cords, Coccygeal,Cords, Lumbar,Cords, Sacral,Cords, Spinal,Cords, Thoracic,Lumbar Cords,Medulla Spinali,Medullari, Conus,Medullaris, Conus,Myelons,Sacral Cords,Spinal Cords,Spinali, Medulla,Spinalis, Medulla,Terminali, Conus,Terminalis, Conus,Thoracic Cords

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