Biomaterial Database

[Effect of application of oxytocin on neurons of Helix pomatia: hyperpolarization effects]. 1988

N I Kononenko, and O N Osipenko

Ionic mechanisms of hyperpolarization induced by oxytocin application on the neuronal membrane of identified neurons of Helix pomatia have been studied under voltage clamp conditions. There are two types of neurons and two types of hyperpolarization, respectively. Hyperpolarization of the first type is due to a decrease in chloride permeability and hyperpolarization of the second type is due to an increase in potassium permeability of the surface neuronal membrane. The reversion potential in the first case was -40 mV and decreased with addition of external solutions of furosemide or tolbutamide. The reversion potential in the second case was -70 mV, and with a 2-fold increase of external potassium concentration it shifted towards depolarization by 15 mV, while tolbutamide addition to the external solution induced no changes. It is supposed that Helix pomatia neurons have different receptors to oxytocin. Activation of some receptors causes a decrease in the membrane permeability for chloride ions, probably, through the system of cyclic nucleotides, while activation of their receptors increases potassium permeability of the surface membrane.

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
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
D010121	Oxytocin	A nonapeptide hormone released from the neurohypophysis (PITUITARY GLAND, POSTERIOR). It differs from VASOPRESSIN by two amino acids at residues 3 and 8. Oxytocin acts on SMOOTH MUSCLE CELLS, such as causing UTERINE CONTRACTIONS and MILK EJECTION.	Ocytocin,Pitocin,Syntocinon
D005665	Furosemide	A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for EDEMA and chronic RENAL INSUFFICIENCY.	Frusemide,Fursemide,Errolon,Frusemid,Furanthril,Furantral,Furosemide Monohydrochloride,Furosemide Monosodium Salt,Fusid,Lasix
D006372	Helix, Snails	A genus of chiefly Eurasian and African land snails including the principal edible snails as well as several pests of cultivated plants.	Helix (Snails),Snails Helix
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
D014044	Tolbutamide	A sulphonylurea hypoglycemic agent with actions and uses similar to those of CHLORPROPAMIDE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p290)	Apo-Tolbutamide,Artosin,Diabetol,Diaval,Dolipol,Orabet,Orinase,Rastinon,Tolbutamid R.A.N.
D014325	Tromethamine	An organic amine proton acceptor. It is used in the synthesis of surface-active agents and pharmaceuticals; as an emulsifying agent for cosmetic creams and lotions, mineral oil and paraffin wax emulsions, as a biological buffer, and used as an alkalizer. (From Merck, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p1424)	Tris Buffer,Trisamine,Trometamol,Tri(hydroxymethyl)aminomethane,Tris(hydroxymethyl)aminomethane,Tris-Magnesium(II)-Potassium Chloride Buffer,Tris-Mg(II)-KCl Buffer,Trizma
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In