A comparison of the effects of serotonin, substance P and thyrotropin-releasing hormone on excitability of rat spinal motoneurons in vivo. 1985

S R White

Lumbar spinal motoneurons of urethane-anesthetized rats were driven at stable low firing rates by automatically cycled iontophoretic applications of glutamate or aspartate. The effects of iontophoretically applied serotonin, substance P or thyrotropin-releasing hormone (TRH) on glutamate or aspartate-evoked activity were then tested. All 3 substances were found to enhance both glutamate- and aspartate-induced excitation of the motoneurons. This enhancement of excitability was usually preceded by a brief period of inhibition at current onset. Although the effects of serotonin and substance P were qualitatively remarkably similar, TRH differed in that TRH occasionally inhibited motoneuron excitability without subsequent facilitation, and tachyphylaxis developed for the facilitatory effects of TRH. After TRH desensitization, serotonin could still enhance spinal motoneuron excitability.

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
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D004357 Drug Synergism The action of a drug in promoting or enhancing the effectiveness of another drug. Drug Potentiation,Drug Augmentation,Augmentation, Drug,Augmentations, Drug,Drug Augmentations,Drug Potentiations,Drug Synergisms,Potentiation, Drug,Potentiations, Drug,Synergism, Drug,Synergisms, Drug
D005971 Glutamates Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure. Glutamic Acid Derivatives,Glutamic Acids,Glutaminic Acids
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
D000870 Anterior Horn Cells MOTOR NEURONS in the anterior (ventral) horn of the SPINAL CORD which project to SKELETAL MUSCLES. Anterior Horn Neurons,Neurons, Anterior Horn,Neurons, Ventral Horn,Ventral Horn Cells,Ventral Horn Neurons,Anterior Horn Cell,Anterior Horn Neuron,Cell, Anterior Horn,Cell, Ventral Horn,Cells, Anterior Horn,Cells, Ventral Horn,Neuron, Anterior Horn,Neuron, Ventral Horn,Ventral Horn Cell,Ventral Horn Neuron
D001224 Aspartic Acid One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter. (+-)-Aspartic Acid,(R,S)-Aspartic Acid,Ammonium Aspartate,Aspartate,Aspartate Magnesium Hydrochloride,Aspartic Acid, Ammonium Salt,Aspartic Acid, Calcium Salt,Aspartic Acid, Dipotassium Salt,Aspartic Acid, Disodium Salt,Aspartic Acid, Hydrobromide,Aspartic Acid, Hydrochloride,Aspartic Acid, Magnesium (1:1) Salt, Hydrochloride, Trihydrate,Aspartic Acid, Magnesium (2:1) Salt,Aspartic Acid, Magnesium-Potassium (2:1:2) Salt,Aspartic Acid, Monopotassium Salt,Aspartic Acid, Monosodium Salt,Aspartic Acid, Potassium Salt,Aspartic Acid, Sodium Salt,Calcium Aspartate,Dipotassium Aspartate,Disodium Aspartate,L-Aspartate,L-Aspartic Acid,Magnesiocard,Magnesium Aspartate,Mg-5-Longoral,Monopotassium Aspartate,Monosodium Aspartate,Potassium Aspartate,Sodium Aspartate,Aspartate, Ammonium,Aspartate, Calcium,Aspartate, Dipotassium,Aspartate, Disodium,Aspartate, Magnesium,Aspartate, Monopotassium,Aspartate, Monosodium,Aspartate, Potassium,Aspartate, Sodium,L Aspartate,L Aspartic Acid
D012701 Serotonin A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator. 5-HT,5-Hydroxytryptamine,3-(2-Aminoethyl)-1H-indol-5-ol,Enteramine,Hippophaine,Hydroxytryptamine,5 Hydroxytryptamine
D013373 Substance P An eleven-amino acid neurotransmitter that appears in both the central and peripheral nervous systems. It is involved in transmission of PAIN, causes rapid contractions of the gastrointestinal smooth muscle, and modulates inflammatory and immune responses. Euler-Gaddum Substance P,Hypothalamic Substance P,SP(1-11),Euler Gaddum Substance P,Substance P, Euler-Gaddum,Substance P, Hypothalamic

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