MORPHOLOGICAL ALTERATIONS IN DENDRITIC SPINES OF RAT HIPPOCAMPAL-NEURONS EXPOSED TO N-METHYL-D-ASPARTATE

Individual cultured rat hippocampal neurons grown on glass coverslips were loaded with lucifer yellow (LY) and segments of their dendrites, containing dendritic spines, were exposed to the glutamate agonist N-m ethyl-D-aspartate (NMDA). Repeated pulse application of NMDA caused a reduction of spine length by 20%, within 1-2 h of exposure to the drug . No such changes were seen in spines exposed to NMDA in presence of t he antagonist 2-aminophosphonovalerate or in spines on sister dendrite s which were not exposed to NMDA. It is suggested that dendritic spine s shrink following exposure to excessive synaptic stimulation.