GM1 Ganglioside treatment after global ischemia protects changes in membrane fatty acids and properties of Na+, K+‐ATPase and Mg2+‐ATPase

Abstract

An examination was made of the effects of ganglioside GM1 (i.m.) on the losses of membrane fatty acids (palmitic, stearic, oleic, linoleic, and arachidonic), the plasma membrane enzyme Na+, K+-ATPase, and the mitochondrial membrane enzyme Mg2+-ATPase, associated with global ischemia 24 hr after permanent unilateral occlusion of the carotid artery in Mongolian gerbils. While there was a significant loss of fatty acids in saline controls, no loss was detected in membranes from GM1-injected gerbils. Rather, we found an increase in membrane fatty acid content, indicative of altered turnover. A 38% loss of Na+, K+-ATPase and a 36% loss of mitochondrial Mg2+-ATPase observed in membranes from saline controls was reduced in membranes from GM1-injected animals to losses of 15% and 8% respectively. These effects are further described by analyses of enzyme kinetics (apparent Vmax and apparent Km). After 1 week of storage, the activities of both membrane ATPases from saline controls decreased substantially more than from GM1-injected animals, suggesting that the GM1 membranes were better "preserved." Since there was a minimal loss in protein content after 24 hr of ischemia, these results indicate that systemically injected GM1 may protect structure and function of plama membranes during the acute phases of ischemic injury.