Direct involvement of protein synthesis in the phase shifts by serotonin in the ocular circadian system of Aplysia

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dc.contributor.advisorEskin, Arnold
dc.contributor.committeeMemberKlass, Michael R.
dc.contributor.committeeMemberHenning, Susan J.
dc.contributor.committeeMemberHecht, Ralph M.
dc.creatorYeung, Jim Sai-Ching
dc.date.accessioned2024-01-24T17:20:27Z
dc.date.available2024-01-24T17:20:27Z
dc.date.issued1985
dc.description.abstractSerotonin (5-HT) regulates the phase of the biological clock located within the eye of Aplysia californica. In this thesis, the direct involvement of protein synthesis in the phase shifts produced by 5-HT was investigated. At the phase when 5-HT produced advance phase shifts, 5-HT seemed to increase incorporation of radioisotope-labelled amino acids into a 34-kilodalton protein with an isoelectric point of 7.2. The result that no noticeable change was observed in the amount of label associated with the 34-kD protein when the eyes were labelled before the 5-HT treatment suggested that the increase in label associated with the 34-kD protein was probably due to an increase in protein synthesis. To investigate whether the 34-kD protein was involved in the circadian timing system, we attempted to correlate the effect of 5-HT on the synthesis of the 34-kD protein with the effect of 5-HT on the circadian rhythm. 5-HT caused phase shifts by activating adenylate cyclase and increasing cAMP. Forskolin, an activator of adenylate cyclase, and 8- benzylthio cAMP (8-BT cAMP), an analogue of cAMP, both mimicked the effect of 5-HT on the circadian rhythm, and both of them also mimicked the effect of 5-HT on the synthesis of the 34-kD protein. Depending on the phase of the circadian rhythm, 5-HT advanced, delayed, or did not affect the circadian rhythm. It was found that 5-HT did not increase the synthesis of the 34-kD protein at a phase when 5-HT did not shift the phase of the circadian rhythm, and 5-HT increased the synthesis of the 34-kD protein at phases when 5-HT delayed or advanced the circadian rhythm. By cutting 5-HT-treated Aplysia eyes into proximal and distal portions, it was found that the effect of 5-HT on the synthesis of the 34-kD protein was not a generalized effect on all parts of the eye. The synthesis of the 34-kD protein occurred mainly in the proximal portion. It is interesting that the proximal portion of the Aplysia eye contains cells or processes that are necessary for the expression of the circadian rhythm. These correlations, when considered together, suggest that the synthesis of the 34-kD protein is directly involved in the phase shift produced by 5-HT.
dc.description.departmentBiology and Biochemistry, Department of
dc.format.digitalOriginreformatted digital
dc.format.mimetypeapplication/pdf
dc.identifier.other12704643
dc.identifier.urihttps://hdl.handle.net/10657/16054
dc.language.isoen
dc.rightsThis item is protected by copyright but is made available here under a claim of fair use (17 U.S.C. Section 107) for non-profit research and educational purposes. Users of this work assume the responsibility for determining copyright status prior to reusing, publishing, or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires express permission of the copyright holder.
dc.subjectCircadian rhythms
dc.subjectAplysia californica
dc.titleDirect involvement of protein synthesis in the phase shifts by serotonin in the ocular circadian system of Aplysia
dc.type.dcmiText
dc.type.genreThesis
thesis.degree.collegeCollege of Natural Sciences and Mathematics
thesis.degree.departmentBiology, Department of
thesis.degree.disciplineBiology
thesis.degree.grantorUniversity of Houston
thesis.degree.levelMasters
thesis.degree.nameMaster of Science

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