Photolytic uncaging of neurotransmitters as a control and stimulation device for neural tissues

• Published in: Proceedings of the Second Joint 24th Annual Conference and the Annual Fall Meeting of the Biomedical Engineering Society] [Engineering in Medicine and Biology Vol. 3; pp. 2072 - 2073 vol.3
• Main Authors: Giszter, S.F., Scabich, J.T., Ellis-Davies, G., Simansky, K.J., Lemay, M.A.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2002
• Subjects: Circuit testing; Control systems; Neural prosthesis; Neurotransmitters; Optical fiber testing; Optical fibers; Optical pulses; Optical transmitters; Recruitment; Spinal cord
• ISBN: 0780376129; 9780780376120
• ISSN: 1094-687X; 1558-4615
• DOI: 10.1109/IEMBS.2002.1053173

Methods are available that can 'cage' neurotransmitters, precluding them from binding with receptors in the nervous system. They are thus rendered biologically inert until photolytic uncaging cleaves their 'cage'. We explored uncaging of MNI-glutamate with implanted fiber optics as a stimulation technology. The spinal cord was bathed in the caged glutamate at different concentrations, and a flash photolysis unit projected brief, spatially concentrated bursts of light into the lumbar spinal cord through a fiberoptic light guide. Forces generated at the ankle were measured in 3 dimensions. Responses were tested at discrete depths in the lumbar cord, with the strongest responses located in the 900 to 1100 /spl mu/m range. Our results indicate feasibility of this approach for engineering a neuroprosthesis. The advantage of this technology is that in principle excitation, inhibition, and modulation state of neural circuits can all be controlled.