Goldfish neurokinin B: Cloning, tissue distribution, and potential role in regulating reproduction

Expression of tachykinin3 and related reproductive markers in the brain of the African cichlid fish Astatotilapia burtoni

“…Tac3 expression in the brain was previously described in zebrafish (Biran et al, ; Ogawa et al, ), goldfish (Qi et al, ), striped bass ( Morone saxatilis ; Zmora, Wong, Stubblefield, Levavi‐Sivan, & Zohar, ), and orange‐spotted grouper (Chen et al, ; Table ). The distribution of tac3a in A. burtoni appears to be more widely distributed than that observed in previously examined teleosts (but see Qi et al []). In grouper and striped bass, expression was limited to the diencephalon, but a thorough neuroanatomical description was not the focus of these studies, so additional smaller cell populations could have been overlooked.…”

“…Detailed neuroanatomical surveys of tac3 expression in the brain currently exist for only zebrafish and goldfish. Zebrafish have restricted expression of tac3a and tac3b throughout the brain (<10 regions for each transcript) (Ogawa et al, ), but a study in goldfish found ubiquitous and identical expression of tac3a and tac3b throughout the entire brain (Qi et al, ), casting doubt on probe specificity and/or accuracy of mapping. As such, a detailed neuroanatomical study on tac3 expression in the brain of a more recently evolved fish is needed.…”

“…Interestingly, kiss1 expression in the habenula was lost in some fishes, including African cichlids, as well as in the western and African clawed frog ( Xenopus tropicalis and Xenopus laevis ) and some mammals (Lee et al, ; Lehman, Merkley, Coolen, & Goodman, ). The gene encoding NKB, tachykinin3 , has multiple forms in some fishes, like zebrafish and goldfish (Biran et al, ; Ogawa et al, ; Qi et al, ), but more recently evolved fishes lost the tac3b gene (Biran et al, ; H. Chen et al, ). A bioinformatics study of the genomes of several African cichlids failed to identify a tac3b gene (Biran et al, ); however, a recent study of Astatotilapia burtoni prohormones identified a potential tac3b gene (Hu et al, ), which has yet to be further investigated.…”

Novel Functional Role of NK3R Expression in the Potentiating Effects on Somatolactin α Autoregulation in grass carp pituitary cells

“…Similar investigations have been recently extended to fish models with the novel findings that the TAC3 gene in fish species, e.g., in zebrafish323334, goldfish35, tilapia36 and grass carp14, not only encodes NKB as the gene product, but also the mature peptide of a new member of tachykinin called NKB-related peptide (NKBRP). Similar to NKB, NKBRP was also effective in stimulating LH release, e.g., in zebrafish32, goldfish35 and tilapia36, suggesting the reproductive function of TAC3 gene products was well conserved throughout vertebrate evolution. Based on our recent in vitro studies in grass carp pituitary cells, interestingly, NKB and NKBRP were found to have no effect on LH secretion and LHβ & GtHα gene expression at the pituitary level but rather serve as novel stimulators for prolactin (PRL) and SLα secretion and gene expression via differential activation of NK2R and NK3R expressed in the carp pituitary14.…”

“…Based on the studies in mammals (e.g., rodent and sheep), NKB was found to be a key regulator for GnRH pulsatility and downstream LH release via NK3R activation in kisspeptin neurons located in the arcuate nuclei within the hypothalamus3031. Similar investigations have been recently extended to fish models with the novel findings that the TAC3 gene in fish species, e.g., in zebrafish323334, goldfish35, tilapia36 and grass carp14, not only encodes NKB as the gene product, but also the mature peptide of a new member of tachykinin called NKB-related peptide (NKBRP). Similar to NKB, NKBRP was also effective in stimulating LH release, e.g., in zebrafish32, goldfish35 and tilapia36, suggesting the reproductive function of TAC3 gene products was well conserved throughout vertebrate evolution.…”