Ionic mechanisms of the rapid (nicotinic) phase of acetylcholine response in identified Planobarius corneus neurones.
Current responses to acetylcholine (ACh) and to suberyldicholine (D-6) applied from the double-barrelled ionophoretic micropipette were studied in two identified neurones (LPed-2 and LPed-3) isolated from the left ganglion of pulmonate mollusc, Planorbarius corneus. Experiments made with K2SO4-filled microelectrodes show that in LPed-2 neurone two kinds of cholinoreceptors are involved in the rapid phase of ACh response one of which induces chloride conductance and the other, sodium conductance. The Cl-dependent component can be separated from the cationic one by C-6 whereas the cationic component can be separated from the Cl--dependent one by furosemide. Cl- conductance can be induced selectively by D-6. In the LPed-3 neurone only Cl- conductance increases during rapid phase of ACh response. The reversal potential of Cl--dependent responses was found to be more negative than the resting potential in experiments made with K2SO4-filled microelectrodes but less negative than the resting potential in the case of KCl-filled microelectrodes. This difference seems to be due to the artificial increase of intracellular chloride concentration.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002712:Chlorides / Q000494:pharmacology; D002794:Choline / Q000031:analogs & derivatives / Q000494:pharmacology; D004553:Electric Conductivity; D005665:Furosemide / Q000494:pharmacology; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008974:Mollusca / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000502:physiology*; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000502:physiology*; D012964:Sodium / Q000494:pharmacology
D002712:Chlorides; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; C009335:subecholine; D005665:Furosemide; D012964:Sodium; D002794:Choline; D000109:Acetylcholine