Role of Glycoproteins in Neural Ontogenesis, Membrane Phenomena, and Memory

Abstract

The structure of membrane-bound glycoproteins is briefly discussed. Glycoproteins are associated with the cell plasma membrane. Their location on the cell surface has led to suggestions that the glycoproteins may have a directing influence on the establishment of the correct cell to cell connections in the developing nervous system. Glycoproteins may be associated with the serotonin receptor, act as a receptor for other transmitters, and may play a role in ionic exchanges at the cell surface. Short-term memory is believed due to rapid conformational changes in the nerve cell membrane, especially in the synoptic region. Long-term memory is believed to be a consequence of the permanent alteration of the membrane due to deposition of glycoprotein material in the cell surface as a consequence of neural stimulation. The glycoproteins thus deposited alter the properties of the membranes. Membrane structure and properties may also be changed by the alteration of the structure of the carbohydrate portion of the glycoproteins as a consequence of neural activity. Alterations in the spatial arrangement of glycoproteins on the neuronal surface may also influence subsequent membrane phenomena. Reference is made to the possibility that turnover of nerve terminals may provide a mechanism of information storage. Difficulties in demonstrating chemical mechanisms of information storage are considered.