Distribution of pituitary adenylate cyclase-activating polypeptide 2 in zebrafish brain

• Published in: Peptides (New York, N.Y. : 1980) Vol. 103; pp. 40 - 47
• Main Authors: Nakamachi, Tomoya, Kamata, Eri, Tanigawa, Ayano, Konno, Norifumi, Shioda, Seiji, Matsuda, Kouhei
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2018
• Subjects: Animals; Distribution; Immunohistochemistry; Pituitary adenylate cyclase activating polypeptide 2; Pituitary Adenylate Cyclase-Activating Polypeptide - metabolism; Real-time PCR; Zebrafish; Zebrafish - metabolism; Zebrafish Proteins - metabolism; Immunohistochemistry; Zebrafish; Real-time PCR; Pituitary adenylate cyclase activating polypeptide 2; Distribution
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2018.03.006

•Zebrafish PACAP2-speciifc antibody is established.•adcyap1b mRNA (coding PACAP2) is dominantly expressed in the zebrafish brain, with the highest level of expression in the telencephalon, followed by the diencephalon.•PACAP2 immunoreactivity was observed in the telencephalon, diencephalon, and cerebellum in the zebrafish brain.•This distribution suggest that PACAP2 is involved in information processing and/or autonomic functions in teleosts. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a multipotent neuropeptide with an amino acid sequence that is well conserved among vertebrates. In teleosts, including zebrafish, the PACAP gene (adcyap1) has been duplicated to yield adcyap1a (coding PACAP1) and adcyap1b (coding PACAP2). This study aims to determine the distribution of these PACAPs and their mRNAs in zebrafish. We generated a zebrafish PACAP2-specific antibody. Using real-time PCR, we observed that adcyap1b mRNA was primarily localized in the brain, with the highest level in the telencephalon, followed by the diencephalon. Using immunostaining of brain tissue samples, PACAP2 immunoreactivity was observed mainly in the telencephalon, hypothalamus, and cerebellum, and the immunopositive fibers formed a line to the habenula. PACAP2-immunopositive cells were observed in the ventral and dorsal regions of the telencephalon and in the hypothalamic nucleus of the diencephalon in the colchicine-injected brain. This distribution of PACAP2 suggests its involvement in higher brain functions in teleosts, such as learning and cognition, as well as instinctive behaviors such as feeding and emotional regulation.