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Published on: September 10, 2019
Melatonin reduces locomotor activity and circulating cortisol in goldfish
Clara Azpeleta1, Rosa María Martínez-Alvarez, María Jesús Delgado
1Departamento Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain.
Hormones and Behavior
|January 19, 2010
Summary
Subchronic melatonin treatment in goldfish reduced locomotor activity and cortisol levels via peripheral injections, suggesting a sedative effect. This effect was not due to reduced food intake, highlighting melatonin
Area of Science:
- Endocrinology
- Neuroscience
- Fish Biology
Background:
- Melatonin, a hormone, influences circadian rhythms and physiological processes in vertebrates.
- Its effects on locomotor activity and stress responses (cortisol) in teleosts, like goldfish, require further investigation.
Purpose of the Study:
- To investigate the impact of subchronic melatonin administration on goldfish locomotor activity and plasma cortisol levels.
- To compare the efficacy of peripheral versus central melatonin delivery routes.
- To determine if melatonin's potential anoretic (appetite-reducing) effect mediates its impact on activity.
Main Methods:
- Goldfish received daily intraperitoneal (peripheral) or intracerebroventricular (central) melatonin injections for 7 or 4 days, respectively.
- Locomotor activity (diurnal, nocturnal, food anticipatory) was monitored daily.
- Plasma cortisol levels were measured, and a separate food restriction experiment was conducted.
Main Results:
- Peripheral melatonin injections significantly reduced daily locomotor activity and plasma cortisol levels.
- Central melatonin injections did not produce significant changes in activity or cortisol.
- Food restriction alone did not alter locomotor activity or cortisol levels, decoupling melatonin's effect from appetite suppression.
Conclusions:
- Peripheral administration of melatonin exerts a sedative effect on goldfish, reducing both motor activity and stress hormone levels.
- These findings suggest a conserved role for melatonin in regulating activity and stress across vertebrate species.
- Melatonin's peripheral action in goldfish is independent of its potential anoretic effects.
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Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...