The nervus terminalis (NT) is a ganglionated vertebrate cranial nerve of unknown function which connects the brain and the peripheral olfactory structures. Studies in the bonnethead shark (Sphyrna tiburo) were conducted to provide basic information on NT ganglion structure and function. / In vivo whole nerve recordings indicate that impulses from the brain suppress the activity of ganglion cells and suggest that synaptic interactions may occur in the ganglion. To understand better these synaptic interactions and the NT ganglion circuit, anatomical and electrophysiological studies were conducted. The NT ganglion contains at least two immunocytochemically distinct populations of cells: one cell type is luteinizing hormone-releasing hormone-immunoreactive (LHRH-ir) and another cell type is LPLRFamide-ir. Anatomical studies also suggest that LHRH-ir cells may receive both cholinergic and catecholaminergic inputs, while LPLRFamide-ir cells may receive cholinergic inputs and little or no catecholaminergic input. / The electrophysiological and pharmacological data is consistent with the anatomical findings, suggesting that at least two populations of cells contribute to whole nerve activity. One cell type may be excited by acetylcholine and depressed by norepinephrine, while another is depressed by acetylcholine and unaffected by norepinephrine. The responses of the NT system suggest that these populations may correspond to the LHRH-ir and LPLRFamide-ir cells, respectively. Intracellular recordings also support the whole nerve data, showing that some cells in the ganglion are spontaneously active, project centrally, and exhibit inhibitory potentials following nerve trunk stimulation. The responses of the few cells tested with pharmacological agents were consistent with those proposed for the LPLRFamide-ir cells. A cholinergic agonist elicited a marked hyperpolarization and a reduction in membrane resistance, while a catecholaminergic agonist had no influence on the cells. / Taken together, the data suggest that the NT ganglion is a complex system with functions unlike those of sensory and autonomic ganglia. / Source: Dissertation Abstracts International, Volume: 50-12, Section: B, page: 5490. / Major Professor: Michael Meredith. / Thesis (Ph.D.)--The Florida State University, 1989.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78137 |
| Contributors | White, Joel Eugene., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 292 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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