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Electrical response of glioma cells to acetylcholine
Abstract:
A bromodeoxyuridine resistant mutant of rat gliom line C6 grown in the presence of N6,02'-dibutyryl adenosine-3':5'-cyclic monophosphate, although inexcitable by electrical current, responds to iontophoretic application of acetylcholine by slow hyperpolarization. The sensitivity to acetylcholine is strongly reduced by excessive amounts of acetylcholine. The hyperpolarization response is inhibited by atropine or alpha-bungarotoxin, but not by D-tubocurarine. In the absence of acetylcholine some cells display spontaneous hyperpolarizations at regular intervals. The membrane resting potential is decreased if the concentration of external K+ is raised.
Insights
This study shows that a specific rat glioma cell line, resistant to bromodeoxyuridine, exhibits acetylcholine-induced hyperpolarization. This response is modulated by acetylcholine concentration and specific blockers, indicating unique receptor characteristics.
Area of Science:
- Neuroscience
- Cell Biology
- Pharmacology
Background:
- Rat glioma C6 cells are a model for studying neuronal properties.
- Cyclic AMP analogs can alter cell excitability and neurotransmitter responses.
- Understanding neurotransmitter receptor function is crucial in neuroscience.
Purpose of the Study:
- To investigate the electrophysiological response of a bromodeoxyuridine-resistant rat glioma C6 cell line to acetylcholine.
- To characterize the acetylcholine-induced hyperpolarization and its sensitivity to various agents.
- To explore spontaneous electrical activity in these cells.
Main Methods:
- Utilized a bromodeoxyuridine-resistant mutant of rat glioma C6 cell line.
- Grew cells in the presence of N6,02'-dibutyryl adenosine-3':5'-cyclic monophosphate.
- Applied iontophoretic acetylcholine and recorded cellular responses.
- Tested the effects of atropine, alpha-bungarotoxin, and D-tubocurarine.
- Manipulated external potassium (K+) concentration.
Main Results:
- The mutant glioma cells, though electrically inexcitable, showed slow hyperpolarization upon acetylcholine application.
- High acetylcholine concentrations reduced the cell's sensitivity.
- Atropine and alpha-bungarotoxin, but not D-tubocurarine, inhibited the hyperpolarization.
- Spontaneous hyperpolarizations were observed in some cells without acetylcholine.
- Increased external K+ decreased the membrane resting potential.
Conclusions:
- Rat glioma C6 mutants possess functional acetylcholine receptors mediating hyperpolarization.
- The receptor subtype appears distinct, showing sensitivity to specific antagonists.
- These cells offer a model for studying acetylcholine receptor pharmacology and ion channel modulation.