Gangliosides and thermal adaptation in vertebrates.

Gangliosides, which are highly enriched in synaptic membranes, show great differences in concentration and pattern constellation as well during early ontogenetical development as on interspecies level in vertebrates. As, up to now, there is no reasonable explanation for these findings, and as it is assumed the synapse to be the primary site of thermal adaptation, the attempt was made to investigate whether there are any correlations between brain gangliosides and the thermal adaptation phenomenon. 1. While in the brains of adult homeothermic vertebrates (with thermo-regulation: mammals, birds) the di-sialoganglioside GD1a predominates, in the brain of poikilotherms (without thermo-regulation: e.g. amphibia, teleost fishes) more polar polysialogangliosides are present. 2. In homeotherms during their early perinatal phase (heterothermic phase: thermor-regulation being not yet developed) a temporary poly-sialisation of brain-gangliosides occurs. 3. In poikilotherms, during the process of thermal adaptation to lowered environmental temperatures, a poly-sialisation of brain gangliosides can be observed, as well during the phase of acclimatization (adaptation to seasonal changes in temperature) as also to acclimation (experimentally induced changes in the environmental temperature). 4. The phenomenon of poly-sialisation of brain gangliosides during adaptation to lowered environmental temperatures can be correlated with changes in some behavioral (e.g. motorical activity) and electrophysiological parameters. 5. On the background of a general hypothesis on the involvement of gangliosides in the process of transmission [23, 24], a functional model on the participation of gangliosides in the process of thermal adaptation is discussed with special regard to the formation of Ca++-ganglioside-complexes, which are highly sensitive to temperature changes.