Excitatory effects of ergot alkaloids and their derivatives on the excitability of an identifiable giant neuron of the African giant snail (Achatina fulica Férussac). 1979

M Miyamoto, and I Yokoi, and A Sakai, and H Takeuchi

The effects of various ergot alkalids and related substances on the neuronal excitability were examined using a spontaneously firing neuron (PON, periodically oscillating neuron) identified in the suboesophageal ganglia of the African giant snail (Achatina fulica Férussac). Of the substances examined, ergometrine and methylergometrine had a marked excitatory effect on the neuron (their critical concentration by bath application: 5 x 10(-6) kg/l). D-lysergic acid (the critical concentration: 3 x 10(-5) kg/l), D-lysergic acid amide (3 x 10(-5), D-lysergic acid 3-hydroxypiperidinamide (3 x 10(-5) and D-lysergic acid 4-hydroxypiperidinamide (10(-4) had also an excitatory effect which was weaker than that of the two alkaloids mentioned above. Agroclavine and elymoclavine had a very slight excitatory effect in some cases. The other substances examined, for example, lysergine, 9, 10-dihydro-D-lysergic acid, 9, 10-dihydro-D-lysergic acid amide, nicergoline, metergoline, methysergide, ergotamine, bromocriptine, lergotrile etc., had no effect on the neuron at a high concentration (10(-4) kg/l). When local (microdrop) application of ergometrine and methylergometrine in the physiological state was performed, the depolarizing shift of the PON membrane and exaggeration of the membrane potential oscillations were observed. In the Na+-free (replaced with Li+) state, local application of the two effective alkaloids produced a marked frequency increase of tonic spike discharges with depolarization of the neuronal membrane.

UI MeSH Term Description Entries
D008094 Lithium An element in the alkali metals family. It has the atomic symbol Li, atomic number 3, and atomic weight [6.938; 6.997]. Salts of lithium are used in treating BIPOLAR DISORDER. Lithium-7,Lithium 7
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
D009474 Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004298 Dopamine One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action. Hydroxytyramine,3,4-Dihydroxyphenethylamine,4-(2-Aminoethyl)-1,2-benzenediol,Dopamine Hydrochloride,Intropin,3,4 Dihydroxyphenethylamine,Hydrochloride, Dopamine
D004876 Ergot Alkaloids Alkaloids originally isolated from the ergot fungus Claviceps purpurea (Hypocreaceae). They include compounds that are structurally related to ergoline (ERGOLINES) and ergotamine (ERGOTAMINES). Many of the ergot alkaloids act as alpha-adrenergic antagonists. Clavine Alkaloids,Alkaloids, Clavine,Alkaloids, Ergot
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
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
D012908 Snails Marine, freshwater, or terrestrial mollusks of the class Gastropoda. Most have an enclosing spiral shell, and several genera harbor parasites pathogenic to man. Snail
D012964 Sodium A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23. Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23

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