N-methyl-D-aspartate effects on the growth, morphology and cytoskeleton of individual neurons in vitro.
Short-term (up to 5 h post-plating) cerebellar granule cell cultures were prepared from the week-old rat and maintained in a micro-incubator during time lapse video microscopy to examine normal and N-methyl-D-aspartate (NMDA)-evoked neurite extension. In untreated cultures growth of neurites was stochastic but proceeded at an average rate of 12.0 +/- 1.4 microns/h. Growth cone morphology was variable. The classical filopodia and lamellipodia possessing tips were motile or non-motile, while those processes ending in a club shape were rarely seen to extend. Individual growth cones passed through several different morphologies during growth. New processes extended more rapidly (13.0 +/- 1.7 microns/h) than those already present (9.0 +/- 0.5 microns/h). Addition of the NMDA receptor antagonist, aminophosphonovalerate (APV), caused a marked retraction of pre-existing processes. Stimulation of the receptor with 50 microM NMDA caused a marked increase in growth rate compared to controls (15.0 microns/h and 1.7 microns/h, respectively). When the presence of actin-rich structures was examined using rhodamine-phalloidin labelling it was found that NMDA increased the proportion of neuronal processes that possessed a growth cone by 28%. Conversely, inhibition of NMDA receptor activity with APV reduced the formation of lamellipodia from neuronal cell bodies.
Department of Biomedical Science, University of Sheffield, UK.
N A
NA
Rashid
M A
MA
Cambray-Deakin
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000648:ultrastructure; D003599:Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure*; D016202:N-Methylaspartate / Q000494:pharmacology*; D016501:Neurites / Q000187:drug effects / Q000648:ultrastructure*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D051381:Rats; D013997:Time Factors
D016202:N-Methylaspartate; D015763:2-Amino-5-phosphonovalerate