Effects of glycolipids on in vitro development of neuromuscular junction

Abstract

THE nervous system has a unique distribution of glycolipids¹, which changes markedly during growth of the animals² and in various inherited metabolic disorders³. No physiological roles for glycolipids in neural function are known, however. But, in nonneural cells glycolipids of the cell membrane are essential for cell recognition and interaction⁴. For example, some gangliosides act as receptors for various bacterial toxins⁵ and globoside has been identified as the human P blood type antigen⁶. When administered in the medium, ganglioside can be incorporated into cell membranes and function as toxin receptors^5,7. Ganglioside added to the medium competes with membrane receptors by binding to the toxins⁵. We reported previously^8,9 that the effects of some drugs and sera on the formation of neuromuscular junction in culture could be evaluated by recording the endplate potential (e.p.p.) from muscle cells combined with the spinal cord. We describe here the effect of glycolipids on the development of neuromuscular junction in culture of skeletal muscle and the spinal cord. Globoside had biphasic effects, an inhibitory effect at the higher concentration and a facilitatory one at the lower concentration or on brief exposure at the beginning of the cultivation. Our evidence suggests that glycolipids are involved in formation of the neuromuscular junction.