Suzannah Bliss Tieman - US grants

The transmission of information in the brain usually involves the passing of particular chemical molecules called neurotransmitters from one nerve cell to another at a functional contact called a synapse. We still do not know the identity of the transmitter from the cells called ganglion cells in the optic nerve, carrying information from the eye to the brain. One candidate for such a transmitter is a peptide abbreviated NAAG that is found in the visual pathways in the brain of several mammals including humans, and appears to act at excitatory sites. This project will use phamacological application of NAAG on preparations of brain slices to compare the effects to those seen in response to direct stimulation of the visual pathways. The distribution of the NAAG in the brain will be examined by immunological and other anatomical tracing techniques. The results will provide evidence whether NAAG is found in the appropriate locations, in the appropriate amounts, and with the appropriate actions, to be considered further as a transmitter. The potential impact of these studies on vision is very great, since knowledge of the transmitter of the cells in the optic nerve, and elsewhere in the visual pathways, will provide a valuable mechanism for manipulating and further understanding how visual information is handled by the brain. Results will be important to other areas of neuroscience, since we do not know the primary transmitter for any of the special senses yet, and also since this compound is found in other regions of the brain.