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dc.contributor.authorRothwell, Cailin
dc.date.accessioned2015-02-04T18:33:26Z
dc.date.available2015-02-04T18:33:26Z
dc.date.issued2015-02-04
dc.identifier.urihttp://hdl.handle.net/10464/6052
dc.description.abstractThe active metabolite of vitamin A, retinoic acid (RA), is involved in memory formation and hippocampal plasticity in vertebrates. A similar role for retinoid signaling in learning and memory formation has not previously been examined in an invertebrate species. However, the conservation of retinoid signaling between vertebrates and invertebrates is supported by the presence of retinoid signaling machinery in invertebrates. For example, in the mollusc Lymnaea stagnalis the metabolic enzymes and retinoid receptors have been cloned from the CNS. In this study I demonstrated that impairing retinoid signaling in Lymnaea by either inhibiting RALDH activity or using retinoid receptor antagonists, prevented the formation of long-term memory (LTM). However, learning and intermediate-term memory were not affected. An additional finding was that exposure to constant darkness (due to the light-sensitive nature of RA) itself enhanced memory formation. This memory-promoting effect of darkness was sufficient to overcome the inhibitory effects of RALDH inhibition, but not that of a retinoid receptor antagonist, suggesting that environmental light conditions may influence retinoid signaling. Since RA also influences synaptic plasticity underlying hippocampal-dependent memory formation, I also examined whether RA would act in a trophic manner to influence synapse formation and/or synaptic transmission between invertebrate neurons. However, I found no evidence to support an effect of RA on post-tetanic potentiation of a chemical synapse. Retinoic acid did, however, reduce transmission at electrical synapses in a cell-specific manner. Overall, these studies provide the first evidence for a role of RA in the formation of implicit long-term memories in an invertebrate species and suggest that the role of retinoid signaling in memory formation has an ancient origin.en_US
dc.language.isoengen_US
dc.publisherBrock Universityen_US
dc.subjectRetinoic aciden_US
dc.subjectOperant conditioningen_US
dc.subjectInvertebrateen_US
dc.titleThe role of retinoic acid in long-term memory formation and synaptic plasticity in the mollusc Lymnaea stagnalisen_US
dc.typeElectronic Thesis or Dissertationen
dc.degree.namePh.D. Biological Sciencesen_US
dc.degree.levelDoctoralen_US
dc.contributor.departmentDepartment of Biological Sciencesen_US
dc.degree.disciplineFaculty of Mathematics and Scienceen_US
dc.embargo.termsNoneen_US
refterms.dateFOA2021-07-31T01:51:08Z


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