[Ionic mechanisms of the effects of phenibut and GABA unrelated to changes in the function of chloride channels].
It is established that beta-phenyl-GABA (phenibut) and partly GABA elicit direct depolarization of the isolated spinal cord motoneurons. The depolarizing effect of phenibut and a depolarizing component of GABA action do not alter in the presence of picrotoxin (10(-5) mol/l) and in the chloride-deficient medium. This depolarizing phenibut effect which is not bound with activation of GABAA-receptors and chloride channels coupled with them does not alter in Na+-deficient medium, enhances in the medium with excess of K+ ions (10 mol/l) and in presence of imidazol (5 . 10(-4) mol/l) and is completely abolished in the Ca2+-deficient medium with 2 mmol/l of Mn2+ or in the presence of 10(-4) mol/l theophylline. It is supposed that phenibut and partly GABA diminish intracellular concentration of cAMP via GABAB-receptor activation and decrease functional activity of voltage-dependent Ca2+-ionic channels and Ca2+-activated outward K+-currents.
D000818:Animals; D000870:Anterior Horn Cells / Q000187:drug effects*; D002712:Chlorides / Q000502:physiology; D000242:Cyclic AMP / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D009046:Motor Neurons / Q000187:drug effects*; D010852:Picrotoxin / Q000494:pharmacology; D011188:Potassium / Q000502:physiology; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects*; D012018:Reflex / Q000187:drug effects; D012964:Sodium / Q000502:physiology; D013806:Theophylline / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*
D002712:Chlorides; D000242:Cyclic AMP; D007093:Imidazoles; D010852:Picrotoxin; D011188:Potassium; D011963:Receptors, GABA-A; D012964:Sodium; D013806:Theophylline; D005680:gamma-Aminobutyric Acid; C029899:imidazole; C008842:4-amino-3-phenylbutyric acid
Ionnye mekhanizmy éffektov fenibuta i GAMK, ne sviazannykh s izmeneniem funktsii khlornykh kanalov.