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Article
Localization and quantification of 5-hydroxytryptophan and serotonin in the central nervous systems of Tritonia and Aplysia
Article first published online: 20 JUL 2001
DOI: 10.1002/cne.1272
Copyright © 2001 Wiley-Liss, Inc.
1096-9861/asset/cover.gif?v=1&s=2642f598baa3ea29c6119ef7bbd2b88f473475ce "The Journal of Comparative Neurology")
Additional Information
How to Cite
Fickbohm, D. J., Lynn-Bullock,, C. P., Spitzer, N., Caldwell, H. K. and Katz, P. S. (2001), Localization and quantification of 5-hydroxytryptophan and serotonin in the central nervous systems of Tritonia and Aplysia. The Journal of Comparative Neurology, 437: 91–105. doi: 10.1002/cne.1272
Publication History
- Issue published online: 20 JUL 2001
- Article first published online: 20 JUL 2001
- Manuscript Accepted: 24 MAY 2001
- Manuscript Revised: 21 MAY 2001
- Manuscript Received: 22 JAN 2001
Funded by
- NIH. Grant Number: NS35371
- Georgia State University Research Program Enhancement grant
- Abstract
- Article
- References
- Cited By
Keywords:
- immunohistochemistry;
- confocal microscopy;
- HPLC-EC;
- colocalization;
- monoamine precursor;
- dopamine
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) plays a central role in several behaviors in marine molluscs and other species. In an effort to better understand the regulation of 5-HT synthesis, we used high performance liquid chromatography (HPLC) with electrochemical detection and immunohistochemistry to measure and map the distribution of the immediate precursor of 5-HT, 5-hydroxytryptophan (5-HTP), in two model opisthobranch molluscs, the nudibranch Tritonia diomedea and the anaspid Aplysia californica. HPLC measurements showed that 5-HTP is present at approximately the same level as the 5-HT metabolite, 5-hydroxyindolacetic acid (5-HIAA) but is more than 100 times lower in concentration than either 5-HT or dopamine in the same tissue. Specific 5-HTP immunoreactivity was colocalized with serotonin in both species. The overall intensity of 5-HTP immunoreactivity in individual ganglia agreed with HPLC measurements for those ganglia. The intensity of 5-HTP immunolabeling varied between cell types and was correlated with the intensity of 5-HT immunolabeling. In particular, differences in staining intensity were consistently seen among the three dorsal swim interneurons of the Tritonia swim central pattern generator circuit. Some nonserotonergic neurons also displayed low levels of 5-HTP immunolabeling that were above background levels. Together, these results support the notion that production of 5-HTP is a rate-limiting step in serotonin synthesis and suggest that there may be additional regulation that allows 5-HTP to accumulate to varying levels. J. Comp. Neurol. 437:91–105, 2001. © 2001 Wiley-Liss, Inc.