Orexins (hypocretins): The intersection between homeostatic and hedonic feeding

Area of Science:

• Neuroscience
• Endocrinology
• Behavioral Science

Background:

• Orexins are hypothalamic neuropeptides initially linked to feeding regulation.
• Their extensive connections to reward circuitry suggest roles beyond homeostatic feeding.
• Emerging evidence implicates orexins in hedonic and appetitive behaviors toward palatable foods.

Purpose of the Study:

• To review the role of orexins in eating-related behaviors, focusing on reward and motivation.
• To explore the neural circuits underlying orexin's effects on feeding.
• To discuss the mechanisms and brain circuitry involved in orexin-mediated behaviors.

Main Methods:

• Literature review of studies on orexins and feeding behavior.
• Analysis of neural circuits connecting orexin neurons to reward pathways.
• Synthesis of findings on orexin's role in homeostatic and hedonic feeding.

Main Results:

• Orexins are involved in both homeostatic feeding and hedonic/appetitive behaviors for palatable foods.
• Orexin neurons connect to mesocorticolimbic circuitry, influencing reward-related behaviors.
• A significant bias exists towards studies involving male subjects, highlighting a need for research in females.

Conclusions:

• Orexins play a crucial role in motivating the pursuit of highly salient rewards, like palatable foods.
• Orexins may act as a critical link between homeostatic and hedonic feeding drives.
• Further research is needed to elucidate orexin's function in female feeding behaviors.