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Feeding increases 5-hydroxytryptamine and norepinephrine within the hypothalamus of chicks
T Tachibana1, M Tazawa, K Sugahara
1United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan. 99901016@cc.utsunomiya-u.ac.jp
Insights
Hypothalamic serotonin (5HT) and norepinephrine (NE) levels change during feeding in chicks. These monoamines in the hypothalamus play a role in regulating chick feeding behavior.
Area of Science:
- Neuroscience
- Animal Behavior
- Biochemistry
Background:
- Hypothalamic serotonin (5HT) and norepinephrine (NE) are implicated in feeding regulation.
- Understanding the dynamic changes of these neurotransmitters during feeding is crucial.
Purpose of the Study:
- To investigate extracellular 5HT and NE levels in the chick hypothalamus during feeding.
- To elucidate the role of hypothalamic monoamines in feeding behavior.
Main Methods:
- Brain microdialysis was employed to collect samples from the hypothalamus.
- High-pressure liquid chromatography with an electrochemical detector was used to measure 5HT, NE, and MHPG (a major NE metabolite).
Main Results:
- Extracellular 5HT levels in the medial hypothalamus (MH) and lateral hypothalamus (LH) increased during the initial 30 minutes of feeding, then returned to baseline.
- NE and MHPG levels in the LH showed an increase during feeding and remained elevated throughout the experiment.
Conclusions:
- The study supports the involvement of hypothalamic monoamines in the regulation of feeding in chicks.
- Dynamic changes in 5HT and NE concentrations suggest their specific roles in initiating and sustaining feeding behaviors.
Abstract:
It is thought that hypothalamic 5-hydroxytryptamine (5HT) and norepinephrine (NE) are involved in the regulation of feeding in chicks. The present study was conducted to elucidate changes in the levels of extracellular 5HT and NE in the hypothalamus during feeding of chicks. In order to measure 5HT, NE and 4-hydroxy-3-methoxyphenylglycol (MHPG), which is a major metabolite of NE, we used brain microdialysis and high-pressure liquid chromatography with an electrochemical detector. After collecting samples to determine the basal levels of 5HT, NE and MHPG, food-deprived birds were given access to food. 5HT levels in the medial hypothalamus (MH) and lateral hypothalamus (LH) increased during the first 30 min of feeding, and then returned to basal levels. NE and MHPG in the LH increased during feeding, and remained elevated throughout the experiment. This study supports an idea that hypothalamic monoamines in the chick brain are involved in the regulation of feeding.