Antiserum to gangliosides inhibits [ 3H]GABA binding to a synaptosome-enriched fraction of rat cerebral cortex

Abstract

1. 1. The effects of various rabbit sera on the binding of [ 3H]GABA (4.6 × 10 −9M) and on the retention of [ 14C]sucrose (1.04 × 10 −7 M) in a synaptosome-enriched fraction of rat cerebral cortex were examined using differential centrifugation and double-isotope methods. 2. 2. Additions of undiluted whole sera (amounting to about 1 5 th of the total volume of suspensions) decreased the binding of [ 3H]GABA, did not affect the retention of [ 14C]sucrose and increased pellet/supernatant [ 14C]sucrose distribution ratios and protein contents of pellets. 3. 3. Only antiserum to total gangliosides-plus-albumin significantly decreased the binding of [ 3H]GABA to a greater extent than did control serum; this effect was not due to albumin antibodies since antiserum to albumin did not affect [ 3H]GABA binding and it was not due to increased protein content of pellets since serum containing hemolyzed erythrocytes (which had a higher protein content than other sera) did not affect [ 3H]GABA binding. 4. 4. Gangliosides might be involved in modulating the interaction of GABA and its synaptic receptors and/or its transport sites.