Immunocytochemical localization of glutamate, glutamine synthetase and glutaminase in the giant new fibers of the crayfish Procambarus clarkii / by Beth McKinnon.
| Author/creator | McKinnon, Beth author. |
| Other author | Kalmus, Gerhard W., degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 1994. |
| Description | 71 leaves : illustrations (1 color) ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | Results from immunocytochemical studies of nerve cords from crayfish, Procambarus clarkii, provide evidence that a "glutamine cycle" exists between glia and the giant axons. Typically, the glutamine cycle is a process by which glutamate, released from nerve terminals is taken up by the glial cells to be converted to glutamine by the enzyme glutamine synthetase, thus terminating its synaptic activity. Glutamine is transported back to the nerve where it is converted to glutamate by phosphate activated glutaminase. It has been known since the 60's that neurotransmitters can also be released by nerve fibers in non-synaptic regions of the nervous system, suggesting that the glutamine cycle may also be involved in the interaction between the axon and its glia and therefore should be further characterized (Wheeler et al.. 1966; Lieberman et al.. 1989). Localization of the key enzymes involved in glutamate metabolism, glutaminase and glutamine synthetase was quantitatively evaluated with the electron microscope using gold labeled antibodies. A polyclonal antiserum was raised against glutamine synthetase in rabbits. Specificity of the antiserum was tested by Western blot analysis. Glutamine synthetase immunoreactivity was found predominantly in the glial cells in accordance with the glutamine cycle model, implicating glia as the site of glutamate breakdown. The phosphate-activated glutaminase, which catalyzes the formation of glutamate from glutamine to replenish the releasable pool of glutamate, would be expected to be localized in the axoplasm. Using a polyclonal antiserum raised in rabbits against glutaminase, our studies confirm the localization of glutaminase-like immunoreactivity in the axons. Glutamate immunoreactivity appeared in both ceil types. This study provides histochemical support for the electrophysiological findings which suggest that glutamate receptors on glial cells respond to glutamate released by the axon during excitation (Lieberman et al., 1989), thus providing further insight into axon-glia interactions. |
| General note | Submitted to the faculty of the Department of Biology. |
| General note | Advisor: Gerhard W. Kalmus |
| Dissertation note | M.S. East Carolina University 1994 |
| Bibliography note | Includes bibliographical references (leaves 63-71). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
| Library | Location | Call Number | Status | Item Actions |
|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
| Electronic Resources | Access Content Online | ✔ Available |