Role of the endocannabinoid system in teleostei fish physiology: implications for reproduction and environmental interactions

The endocannabinoid system (ECS) represents a vital neurotransmitter network in vertebrates, regulating neurogenesis, cognition, lipid metabolism, and immune activity. One of the vertebrates used for studying the endocannabinoid system is fish, specifically the species Danio rerio, known as zebrafish, due to its similarities with vertebrate development. This review explores the ECS in teleost fishes, emphasising its role in reproductive physiology and its interaction with environmental pollutants. Although extensive research has elucidated the ECS in mammals, limited data exist for teleosts. The literature revealed that endocannabinoids in Teleostei have an essential role in lipid metabolism, with effects revealed mainly in the brain and liver involving gene expression processes that regulate these metabolic pathways. Another key role of the endocannabinoid system in fish is in reproduction, as lipid metabolism directly influences gonadal function. Environmental pollutants, such as bisphenol A and phthalates, also disrupt ECS function, impairing reproductive performance and metabolic stability. These findings underscore the need for further studies on teleost-specific ECS mechanisms and their implications for aquatic ecosystems.