Very low concentrations of acetylcholine and GABA modulate transmitter responses.
Acetylcholine and GABA, at extremely low concentrations (10(-14) to 10(-8) M) which do not induce electrical responses, each modulate the chloride-dependent responses of Aplysia neurons to higher concentrations of the same transmitters. Low concentrations of acetylcholine cause a reduction of the response to both acetylcholine and GABA, while low concentrations of GABA cause a facilitation of responses to both acetylcholine and GABA. These effects have a clear threshold, are slow in onset, reversible with prolonged washing, and blocked by cooling.
Ayrapetyan
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S
Wadsworth Center for Laboratories and Research, New York State Department of Health and School of Public Health, Albany, New York 12201-0509.
Carpenter
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D
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001048:Aplysia; D002712:Chlorides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010477:Perfusion / Q000379:methods; D011188:Potassium / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D002712:Chlorides; D005680:gamma-Aminobutyric Acid; D000109:Acetylcholine; D011188:Potassium