EFFECTS OF GM1-GANGLIOSIDE AND ALPHA-SIALYL CHOLESTEROL ON AMINO-ACID-UPTAKE, PROTEIN-SYNTHESIS, AND NA+, K+-ATPASE ACTIVITY IN SUPERIOR CERVICAL AND NODOSE GANGLIA EXCISED FROM ADULT-RATS

We examined the effect of GM1-ganglioside in combination with cholera toxin B, and synthetic alpha-sialyl cholesterol (alpha-SC) on neutral amino acid (tritiated alpha-aminoisobutyric acid, [H-3]AIB) uptake, protein synthesis ([H-3]leucine incorporation), and Na+, K+-ATPase activity in isolated superior cervical ganglia (SCG) and nodose ganglia (NG) from adult rats after aerobic incubation, usually for 2 h at 37-degrees-C in vitro. Cholera toxin B, that specifically masks the oligosaccharide chain of GM1-ganglioside, antagonized the GM1-induced changes in [H-3]AIB uptake, [H-3]leucine incorporation, and Na+, K+-ATPase acitivity almost completely in SCG, but partially in NG. Although cholesterol itself had little effect on either [H-3]AIB uptake and Na+, K+-ATPase activity both in SCG and NG, alpha-SC caused considerable reduction of both amino acid uptake and the transport enzyme activity in each ganglia. However, cholesterol was more effective than alpha-SC in decreasing [H-3]leucine incorporation in either ganglia. Whereas addition of EGTA markedly reduced either GM1-induced or alpha-SC-induced change in [H-3]leucine incorporation into acid-insoluble fraction in both SCG and NG, application of Ca2+ ionophore produced considerable recovery of the protein synthesis from the inhibited level by Ca2+ -deprivation. ATP and creatine phosphate contents in SCG were elevated by the presence of GM1 or alpha-SC, whereas [H-3]AIB uptake and Na+, K+-ATPase activity were inhibited, suggesting that utilization for membrane transport was diminished as a result of GM1- or alpha-SC-induced decrease of ATPase activity.