Chapter 9: Double-label immunofluorescence: a simple and effective tool to study pituitary regulation in teleost fish

VISSIO, PAULA; PEREZ SIRKIN, DANIELA; DI YORIO, MARÍA P.

Cellular and molecular approaches in fish biology

Elsevier

Lugar: Londres; Año: 2022; p. 1 - 438

Neuroendocrinology is the field of biology that studies the interaction betweenthe endocrine and the nervous system. External (temperature, photoperiod, social interactions, and food availability, among others) and internal (for example,metabolic state and stress) information are integrated within the brain and transduced into neural and neuroendocrine signals that control the different organs,leading to the maintenance of homeostasis in vertebrates. The hypothalamic?pituitary axis is the key system that rules all processes in an organism. Thus, thestudy of this axis is fundamental to address how different environmental factorsmodify neuropeptide levels and how these neuropeptides interact between themto regulate metabolic functions.Since fish development, growth, reproduction, and behavior are especiallysusceptible to environmental conditions (such as photoperiod, temperature, water quality, crowding, and food quality), neuroendocrine studies could provideimportant clues on how they impact fish physiology, as well as informationto improve aquaculture rearing practices by developing new techniques andstrategies for better fish welfare. A classic example of the potential applicationof neuroendocrine studies in aquaculture is the case of gonadotropin-releasinghormone (Gnrh), the main factor that triggers reproduction. From the first reportthat demonstrated that Gnrh stimulates gonadotropin secretion (Breton et al.,1972), to the continuous characterization of Gnrh isoforms in fish (Sherwoodet al., 1983; Tostivint, 2011; Roch et al., 2014; Muñoz-Cueto et al., 2020) and their regulation by environmental conditions (Maitra and Hasan, 2016; reviewedin Volkoff, 2016), the study of the Gnrh system was fundamental to adequateprotocols that substantially improved ovulation, spermiation, and/or spawningperformance in species in which spontaneous reproduction was difficult in captivity (Muñoz-Cueto, 2009).Besides possible aquaculture applications, it is worth to investigate the neuroendocrine system from the viewpoint of comparative endocrinology, to get apicture of the complex evolution of this system through the vertebrate?s history.In this sense, fish neuroanatomy makes them exceptional models for studyingthe function and evolution of this system (Golan et al., 2015), as they conservethe major factors that regulate the same functions as in tetrapods.