Oxytocin Signaling Acts as a Marker for Environmental Stressors in Zebrafish

Abstract

The oxytocin system plays a role in stress responses and behavior modulation. However, the effects of oxytocin signaling on stress adaptation remain unclear. Here, we demonstrated the roles of oxytocin signaling as a biomarker under stress conditions in the peripheral tissues (the gills) and central nervous system (the brain). All the environmental stressors downregulated the expression of oxytocin receptors in the gills, and the alteration of the expression of oxytocin receptors was also found in the brain after the acidic (AC) and high-ammonia (HA) treatments. The number of oxytocin neurons was increased after double-deionized (DI) treatment. By transgenic line, Tg(oxtl:EGFP), we also investigated the projections of oxytocin neurons and found oxytocin axon innervations in various nuclei that might regulate the anxiety levels and aggressiveness of adult zebrafish under different environmental stresses. The oxytocin system integrates physiological responses and behavioral outcomes to ensure environmental adaptation in adult zebrafish. Our study provides insight into oxytocin signaling as a stress indicator upon environmental stressors.

Altered GABAergic, glutamatergic and endocannabinoid signaling is accompanied by neuroinflammatory response in a zebrafish model of social withdrawal behavior

“…Therefore it is important to further link neural circuits displaying aberrant activity, with excessive IL-1β expression within SDMN regions, in MK-801-treated fish. Toward that direction, Dm a putative homologous to the mammalian basolateral amygdala (BLA) and PM, a part of the preoptic area, are key nodes in the SDMN ( O'Connell and Hofmann, 2011 ), regulate both social behavior ( Bickart et al, 2014 ; Nunes et al, 2021 ) as well as fear and anxiety-related responses ( Lal et al, 2018 ; Chuang et al, 2021 ), so it is logical to considered as targets of great importance. The enhanced expression of IL-1β may alter synaptic plasticity in these brain regions, contributing to social impairments and anxiety-like behavior, observed in MK-801-treated fish.…”

Revealing the Increased Stress Response Behavior through Transcriptomic Analysis of Adult Zebrafish Brain after Chronic Low to Moderate Dose Rates of Ionizing Radiation

“…The use of RNA in situ hybridization on adult brain demonstrated an upregulation of oxt in the anterior part of the parvocellular preoptic nucleus (PPa). It expresses several neurohormones such as oxytocin or arginine-vasopressin with conserved function compared to mammals [ 103 ] such as the regulation of water homeostasis [ 104 ], the control of blood pressure [ 105 ] as well as a role in social behavior and the regulation of anxiety [ 49 , 50 , 106 ]. Interestingly, a recent analysis of the stress response in zebrafish correlated to the increased number of oxytocinergic cells in the brain with environmental stress provoked by immersion in deionized water for 24 h [ 50 ].…”

“…It expresses several neurohormones such as oxytocin or arginine-vasopressin with conserved function compared to mammals [ 103 ] such as the regulation of water homeostasis [ 104 ], the control of blood pressure [ 105 ] as well as a role in social behavior and the regulation of anxiety [ 49 , 50 , 106 ]. Interestingly, a recent analysis of the stress response in zebrafish correlated to the increased number of oxytocinergic cells in the brain with environmental stress provoked by immersion in deionized water for 24 h [ 50 ]. Other experiments in rodents revealed that repeated defeat experiences increased the number of oxytocinergic neurons in the PVN as well as after chronic homotypic stress [ 107 , 108 ].…”

“…Moreover, in rodents, oxytocin can interact with the dopaminergic system or the serotoninergic system to influence a social response and to regulate anxiolytic effects, especially via the 5-HT1A and 5-HT2A/C receptors [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. In zebrafish, somas of oxytocin neurons are found in the parvocellular preoptic nucleus corresponding to the paraventricular nucleus of the hypothalamus in rodents and in the periventricular nucleus of the posterior tuberculum [ 48 , 49 , 50 ]. As in mammals, oxytocin was also demonstrated to play a role in sociability in the zebrafish, notably in the development and maintenance of social behavior through oxytocin receptors (oxtr and oxtrl) [ 49 , 51 ].…”

Elevated Oxytocin Receptor Blood Concentrations Predict Higher Risk for, More, and Earlier 24-Month Hospital Readmissions after In-Patient Detoxification in Males with Alcohol Use Disorder

“…From a mechanistic point of view, smoking-induced alterations in HPA axis activity might account for this association. Elevated cortisol levels in smokers versus non-smokers are well-established [ 57 ] and preclinical research demonstrated that environmental stressors downregulate OXTR expression in both peripheral and brain tissues of zebrafish [ 58 ]. On the other hand, Kanamori et al [ 59 ] reported increased OXTR concentrations in the uterine myometrium in smoking versus non-smoking pregnant women and positive correlations with the number of daily cigarettes consumed and the concentration of exhaled carbon monoxide.…”