Inhibitory neurotransmitter serotonin and excitatory neurotransmitter dopamine both decrease food intake in Chinese...

Area of Science:

• Neuroendocrinology
• Fish Physiology
• Comparative Nutrition

Background:

• Aminergic neurotransmitters are crucial for regulating food intake.
• The specific roles of serotonin (5-HT) and dopamine (DA) in fish feeding remain largely uncharacterized.
• Understanding these mechanisms is vital for aquaculture and fish health management.

Purpose of the Study:

• To investigate the effects of central administration of serotonin (5-HT) and dopamine (DA) on food intake in Chinese perch (Siniperca chuatsi).
• To examine the impact of these neurotransmitters on the expression of key appetite-regulating genes: neuropeptide Y (NPY), agouti gene-related protein (AgRP), and pro-opiomelanocortin (POMC).

Main Methods:

• Intraventricular (ICV) administration of 5-HT and DA in Chinese perch.
• Quantification of food intake at 1 hour post-injection.
• Measurement of mRNA expression levels of NPY, AgRP, and POMC using quantitative PCR.

Main Results:

• Intraventricular 5-HT significantly decreased food intake in a dose-dependent manner.
• 5-HT administration led to decreased NPY and AgRP mRNA expression and increased POMC mRNA expression.
• DA significantly reduced food intake and AgRP mRNA expression, suggesting mediation through AgRP.

Conclusions:

• Serotonin and dopamine act as inhibitory regulators of food intake in Chinese perch.
• The effects of 5-HT on feeding are likely mediated through the NPY, AgRP, and POMC pathways.
• Dopamine's anorectic effect may be partly explained by its influence on AgRP expression, offering novel insights into fish appetite control.