ISSN:
1573-6830
Keywords:
acetylcholine
;
γ-aminobutyric acid
;
α-bungarotoxin
;
membrane receptor
;
phosphorylation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary 1. Using internally dialyzed neurons ofHelix, we have examined the effects of sodium-pump activity and intracellular ATP concentration on transmembrane currents induced by acetylcholine (ACh) andγ-aminobutyric acid (GABA). We also report on the effects of pump activity and levels of intracellular ATP on binding byHelix ganglia of3H-α-bungarotoxin (3H-α-BT) and3H-GABA. 2. Both ouabain-containing and potassium-free solutions depressed the neurotransmitter-induced transmembrane current of one type of dialyzed neurons. 3. An increase in the intracellular ATP concentration led to a depression of ACh-induced currents and to the disappearance of the blocking effect of ouabain on these currents. Intracellular ADP had a similar but smaller effect on transmitter-induced currents, and intracellular AMP was ineffective. The depressing effect of internal ATP on ACh-induced currents was absent in the presence of an inhibitor of membrane phosphorylation (dinitrophenol). 4. The binding of tritium-labeledα-BT and GABA to the membranes was depressed by both ouabain-containing and K-free solutions and also by compounds (theophylline and NaF) which increase the levels of intracellular ATP. 5. The results suggest that the Na pump modulates the affinity of ACh and GABA membrane receptors by the regulation of the phosphorylated state of membrane receptors.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00711009
Permalink