Learn More
Although environmental, social and physical stressors have been shown to inhibit food intake and feeding behavior in fish, little is known about the mechanisms that mediate the appetite-suppressing effects of stress. Since the hypothalamic-pituitary-interrenal (HPI) axis is activated in response to most forms of stress in fish, components of this axis may(More)
We describe duplicate leptin genes in zebrafish (Danio rerio) that share merely 24% amino acid identity with each other and only 18% with human leptin. We were also able to retrieve a second leptin gene in medaka (Oryzias latipes). The presence of duplicate leptin genes in these two distantly related teleosts suggests that duplicate leptin genes are a(More)
Environmental hypercapnia induces a respiratory acidosis that is usually compensated within 24-96 h in freshwater fish. Water ionic composition has a large influence on both the rate and degree of pH recovery during hypercapnia. Waters of the Amazon are characteristically dilute in ions, which may have consequences for acid-base regulation during(More)
Although elevated plasma cortisol levels and a reduction in food intake are common features of the response to stress in fish, the potential role of cortisol in the regulation of food intake in these animals is poorly understood. In this study, goldfish (Carassius auratus) were fed ad libitum for 21 days diets prepared to contain 0 (Control), 50 (Low) or(More)
The dynamic relationships between the changes in cortisol synthesis during and after a stressor and the expression pattern of the key genes that regulate the different levels of the hypothalamic-pituitary-interrenal (HPI) stress axis are poorly understood. This study established a novel vortex stressor and characterized its impact at all levels of the HPI(More)
The brain, particularly the hypothalamus, integrates input from factors that stimulate (orexigenic) and inhibit (anorexigenic) food intake. In fish, the identification of appetite regulators has been achieved by the use of both peptide injections followed by measurements of food intake, and by molecular cloning combined with gene expression studies.(More)
In fish, the catecholamine hormones adrenaline and noradrenaline are released into the circulation, from chromaffin cells, during numerous 'stressful' situations. The physiological and biochemical actions of these hormones (the efferent adrenergic response) have been the focus of numerous investigations over the past several decades. However, until(More)
Fish urotensin I (UI), a member of the corticotropin-releasing hormone (CRH) family of peptides, is a potent inhibitor of food intake in mammals, yet the role of UI in the control of food intake in fish is not known. Therefore, to determine the acute effects of UI on appetite relative to those of CRH, goldfish were given intracerebroventricular (i.c.v.)(More)
The transition from aquatic to aerial respiration is associated with dramatic physiological changes in relation to gas exchange, ion regulation, acid-base balance and nitrogenous waste excretion. Arapaima gigas is one of the most obligate extant air-breathing fishes, representing a remarkable model system to investigate (1) how the transition from aquatic(More)
The key strategy for coping with elevated brain ammonia levels in vertebrates is the synthesis of glutamine from ammonia and glutamate, catalyzed by glutamine synthetase (GSase). We hypothesized that all four GSase isoforms (Onmy-GS01-GS04) are expressed in the brain of the ammonia-intolerant rainbow trout Oncorhynchus mykiss and that cerebral GSase is(More)