The effect of antibodies to gangliosides on Ca2+ channel-linked release of gamma-aminobutyric acid in rat brain slices.
Antibodies to GM1 ganglioside enhance the release of gamma-aminobutyric acid (GABA) from rat brain slices induced by depolarization with either 40 mM K+ or 200 microM veratrine. Three new observations are now reported. (a) GABA release induced by the Ca2+ ionophore A23187 was not affected by these antibodies. Because this Ca2+ ionophore causes transmitter release by bypassing depolarization-induced opening of Ca2+ channels, this result suggests that gangliosides participate either in the functioning of such Ca2+ channels or in the Na+ channels involved in depolarization. (b) The enhancement (by antibodies to GM1 ganglioside) of GABA release induced by high K+ levels occurred in the presence of tetrodotoxin (0.01 microM). (c) GABA release induced by veratrine in the absence of Ca2+ was not affected by the antibodies. These latter two observations indicate that Na+ channels are not involved in the action of the antibodies. We conclude that this evidence points to the participation of gangliosides in Ca2+ channel functions involved in GABA release in rat brain slices.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D005677:G(M1) Ganglioside / Q000276:immunology / Q000502:physiology*; D007106:Immune Sera / Q000494:pharmacology; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology; D014702:Veratrine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D007106:Immune Sera; D007473:Ion Channels; D005677:G(M1) Ganglioside; D000001:Calcimycin; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; D014702:Veratrine; D011188:Potassium; D002118:Calcium