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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:29 |
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Conference: Bucharest University Faculty of Physics 2010 Meeting
Section: Biophysics and Medical Physics;Electricity and Magnetism
Title:
Sensitivity to algesic stimuli and growth factors in neurite endings of cultured newborn rat primary sensory neurons
Authors:
S. Dumitru, T. Selescu, B. Amuzescu, G. Cocina, N. Pascu, M.L. Flonta
Affiliation:
Dept. Biophysics & Physiology, Faculty of Biology, University of Bucharest
E-mail
bogdan@biologie.kappa.ro
Keywords:
primary sensory neuron, compartmented culture, growth cone, calcium imaging, NGF, BDNF, nociception
Abstract:
Since their discovery by Ramón y Cajal in 1890, growth cones have been the target of complex studies implying the mechanisms of neuronal differentiation and plasticity, dendritic and axonal growth and guidance involving microtubule and actin filaments polymerization/depolymerization. The endings of neurites grown in NGF gradient by primary sensory neurons (PSN) maintained in vitro in a compartmented culture system (Campenot et al. 1977) represent a unique opportunity for studying their sensitivity to growth factors and noxious stimuli. Tang et al. (2003) discovered the role of semaphorin 3 as an inhibitor of rat DRG PSN nociceptive endings developed in response to NGF. The chains of enzyme reactions required for NGF cellular signaling and the survival of cells in the presence of NGF due to its binding to the TrkA receptor are complex, and the fact that the p75 receptor can either send signals for apoptosis or cell survival is not yet fully understood.
The aim of the current study is to initiate research attempting to verify/review currently accepted models of pain sensitivity in neurites of immature PSN, to assess the influence exerted by different growth factors, such as NGF, BDNF, etc., on responses to painful stimuli, and ultimately to provide novel solutions to challenging problems such as neuropathic pain and nerve degeneration. We performed immunofluorescence experiments, as well as extracellular potential recording on neurites and calcium imaging of growth cones upon loading with a non-ratiometric long-wavelength low affinity fast Ca2+ dye (Calcium Green 1 AM) within tests in which we applied NGF 10 ng/ml, BDNF 10 ng/ml, capsaicin 1 {micro}M, menthol 100 {micro}M, and ATP 100 {micro}M or pH 6.0 solutions. Our results prove mild increases in fluorescence elicited by BDNF, sensitization by NGF of responses to capsaicin, and weak responses to menthol recorded as a brief series of spikes.
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