Cloning and expression of tachykinins and their association with kisspeptins in the brains of zebrafish
Article first published online: 7 JUL 2012
Copyright © 2012 Wiley Periodicals, Inc.
Journal of Comparative Neurology
Volume 520, Issue 13, pages 2991–3012, 1 September 2012
How to Cite
Ogawa, S., Ramadasan, P. N., Goschorska, M., Anantharajah, A., We Ng, K. and Parhar, I. S. (2012), Cloning and expression of tachykinins and their association with kisspeptins in the brains of zebrafish. J. Comp. Neurol., 520: 2991–3012. doi: 10.1002/cne.23103
- Issue published online: 7 JUL 2012
- Article first published online: 7 JUL 2012
- Accepted manuscript online: 20 MAR 2012 02:20AM EST
- Manuscript Accepted: 14 MAR 2012
- Manuscript Revised: 29 JAN 2012
- Manuscript Received: 9 AUG 2011
- the Ministry of Science, Technology, and Innovation, Malaysia. Grant Number: 02-02-10-SF0044
- Monash University Sunway Campus. Grant Numbers: Research Grants M-2-2-06, SO-10-01, MM-2-5-06, MM-6-08
The tachykinins are a family of neuropeptides, including substance P (SP), neurokinin A (NKA), and neurokinin B (NKB), that are encoded by the tac1 (SP and NKA) or tac2/3 (NKB) genes. Tachykinins are widely distributed in the central nervous system and have roles as neurotransmitters and/or neuromodulators. Recent studies in mammals have demonstrated the coexpression of NKB and kisspeptin and their comodulatory roles over the control of reproduction. We have recently identified two kisspeptin-encoding genes, kiss1 and kiss2, in teleosts. However, such relationship between tachykinins and kisspeptins has not been demonstrated in non-mammalian species. To determine the involvement of tachykinins in the reproduction in teleosts, we identified tac1 and two tac2 (tac2a and tac2b) sequences in the zebrafish genome using in silico data mining. Zebrafish tac1 encodes SP and NKA, whereas the tac2 sequences encode NKB and an additional peptide homologous to NKB (NKB-related peptide). Digoxigenin in situ hybridization in the brain of zebrafish showed tac1 mRNA-containing cells in the olfactory bulb, telencephalon, preoptic region, hypothalamus, mesencephalon, and rhombencephalon. The zebrafish tac2a mRNA-containing cells were observed in the preoptic region, habenula, and hypothalamus, whereas the tac2b mRNA-containing cells were predominantly observed in the dorsal telencephalic area. Furthermore, we examined the coexpression of tachykinins and two kisspeptin genes in the brain of zebrafish. Dual fluorescent in situ hybridization showed no coexpression of tachykinins mRNA with kisspeptins mRNA in hypothalamic nuclei or the habenula. These results suggest the presence of independent pathways for kisspeptins and NKB neurons in the brain of zebrafish. J. Comp. Neurol. 520:2991–3012, 2012. © 2012 Wiley Periodicals, Inc.