Interactions of G_M1 Ganglioside with Crude Rat Brain Neuronal Membranes

Abstract

The binding of GM1 ganglioside to crude preparations of rat brain neuronal membranes was studied, the following results being obtained: (a) the binding process followed a biphasic kinetics, which displayed a break at 0.07-0.08 x 10(-6) M GM1 concentration; (b) the features of the binding process at GM1 concentrations below the break and, over the break, above 10(-6) M appeared to be different. Below the break the process proceeded slowly and brought a stable and irreversible association of GM1 molecules to the membranes. Over 10(-6) M the process was much more rapid and caused GM1 molecules to interact in such a way that they were releasable by washing and could exchange with newly added free ganglioside; (c) the two binding processes displayed the characteristics of a saturation phenomenon; (d) in both cases, GM1 taken up was freely available to galactose oxidase, indicating that the oligosaccharide chains protrude from the membrane surface. We postulate that GM1 occurs, below and above the break, in different physical forms, each of them having a different mechanism of interaction with the membrane. Above 10(-6) M GM1 interacts as micelles, and the basis of the micelle-membrane interaction is a fusion process. Below the break, in the 10(-8)--10(-7) M range, the binding is the result of hydrophobic interactions between sites on the membrane and the hydrophobic portion of individual ganglioside molecules, most likely in the monomeric form.

Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa

“…Data on the effect of ganglioside micelles on neuronal cells have suggested a possible mediation of monomers, which escape from micelles during the micellemembrane interaction. [83][84][85] Under our experimental conditions, ganglioside monomers from the surrounding cryoprotective media are not likely to have been inserted into the ganglioside-containing membrane lipid rafts because their insertion is known to be temperature-dependent and quite unlikely to occur at 4 uC. 86 At the present stage of research, these hypotheses require further investigations that rely on direct physicochemical methods.…”

“…21 We established that 43% and 73% of ganglioside micelles are removed in two washes, respectively, 64 and they can therefore be assumed to simply adhere to the membrane surface through ion or hydrogen bonds. 83 It appears that ganglioside micelles, which are loosely attached to the sperm cell membrane, increase membrane hydrophobicity during cryopreservation. Data on the effect of ganglioside micelles on neuronal cells have suggested a possible mediation of monomers, which escape from micelles during the micellemembrane interaction.…”

Gangliosides potentiate in vivo and in vitro effects of nerve growth factor on central cholinergic neurons.

“…The interaction of the ganglioside with endogenous trophic factors, and with ,B-NGF in particular, could take place at any level. Nevertheless, it is likely that this interaction occurs at the level of the cell membrane where GM1 is incorporated (25). In this regard, it is interesting that immobilized GM1 is capable of binding P-NGF with low affinity (26).…”

Effect of the ganglioside GM1, on cerebral metabolism, microcirculation, recovery kinetics of ECoG and histology, during the recovery period following focal ischemia in cats.

“…15 In fact, the interaction of the gangliosides with brain membranes is reportedly accompanied by various metabolic effects including increased adenylate cyclase, 16 increased phosphodiesterase activity, 17 enhanced dopamine release 18 and modification of (Na + , K + ) ATPase activity.…”