836825

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836825 [2018/11/22 21:16] (current)
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 +====== gamma-Aminobutyric acid-stimulated chloride permeability in crayfish muscle.======
 +
 +** Article date:** 1977/2/4
 +~~META:date created = 1977-02-04~~
 +
 +** PubMed ID: 836825 **
 +
 +** Journal name: Biochimica et biophysica acta (ISSN: 0006-3002) **
 +
 +** ABSTRACT **
 +
 +gamma-Aminobutyric acid selectively increased Cl- permeability in isolated strips of crayfish abdominal muscle. Muscle fibers incubated in Van Harrevald'​s solution at room temperature took up 36Cl- to the extent of 700 ml/kg wet weight with a halftime of 2.5 min. During 15-S incubations,​ the control 36Cl- uptake space was 131 +/- 4 ml/kg (n = 60) and this was significantly increased by gamma-aminobutyric acid at 200 muM or higher concentrations to 177 +/- 4 ml/kg (n = 48, P less than 0.05). This effect was specific for chloride since gamma-aminobutyric acid did not increase the uptake by crayfish muscle of radioactive sucrose, inositol, or propionate. gamma-Aminobutyric acid stimulation of 36Cl- uptake is mediated by receptor-ionophore function since the process shows pharmacological properties virtually identical to those observed by electrophysiological techniques. The gamma-aminobutyric acid stimulation of Cl- permeability is dose dependent with 50% of the maximal effect at 40 muM gamma-aminobutyric acid and the dose vs. response curve is somewhat sigmoid. The gamma-aminobutyric acid agonist muscimol causes the same maximal effect on Cl- uptake as gamma-aminobutyric acid, but acts at 5-fold lower concentrations,​ i.e. is more potent. However, the partial agonist gamma-amino,​ beta-hydroxybutyric acid produced little or no stimulation of 36Cl- flux. The response to gamma-aminobutyric acid was blocked by 2 mM beta-guanidinopropionate or gamma-guanidinobutyrate,​ 0.5 mM bicuculline,​ and 10 muM picrotoxinin. Picrotoxinin inhibition was dose dependent with 50% inhibition occurring at 4 muM. Antagonists did not affect control 36Cl- uptake. These results confirm electrophysiological observations that the postsynaptic response to the inhibitory neurotransmitter gamma-aminobutyric acid involves a rapid increase in membrane permeability to Cl-.
 +
 +===== ===== 
 +
 +{{gview 100%,​450px>​ http://​directlinks.cc/​files/​muscimol/​836825.pdf}}
 +
 +Author List: Ticku M K, Olsen R W
 +
 +Publication Types: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.
 +
 +Substances mentioned in the article: Aminobutyrates;​ Chlorides; Picrotoxin; gamma-Aminobutyric Acid; 
 +
 +Mesh terms: Aminobutyrates/​pharmacology;​ Animals; Astacoidea/​metabolism;​ Biological Transport; Chlorides/​metabolism;​ Kinetics; Muscles/​drug effects; Permeability;​ Picrotoxin/​pharmacology;​ Structure-Activity Relationship;​ gamma-Aminobutyric Acid/​pharmacology; ​
 +
 +{{tag> Chlorides Picrotoxin Aminobutyrates gamma-Aminobutyric_Acid }}
 +
 +{{keywords>​ Chlorides, Picrotoxin, Aminobutyrates,​ gamma-Aminobutyric Acid}}
 +
  
836825.txt · Last modified: 2018/11/22 21:16 (external edit)