Brain POMC Neurons: Comparative Aspects of Anatomy, Peptide Processing and Function

Area of Science:

• Neuroscience
• Endocrinology
• Evolutionary Biology

Background:

• Proopiomelanocortin (POMC) peptides are crucial neuromodulators involved in feeding, body mass regulation, and analgesia.
• Two main POMC neuron populations exist in the mammalian brain: hypothalamic (long-term control) and brainstem (rapid control).
• The evolutionary history and function of POMC systems, particularly in non-mammalian vertebrates and agnathans, remain largely unknown.

Purpose of the Study:

• To review the current knowledge on the location, post-translational processing, and function of POMC peptides in the vertebrate brain.
• To highlight unanswered questions regarding POMC neuron evolution and their role in energy homeostasis and nutrient signaling.
• To summarize the distinct roles of hypothalamic and brainstem POMC neurons.

Main Methods:

• Literature review and synthesis of existing research on POMC neurons and peptides across vertebrate species.
• Comparative neuroanatomy of POMC systems in different vertebrate groups.
• Analysis of functional studies on POMC peptide roles in feeding, metabolism, and analgesia.

Main Results:

• Hypothalamic POMC neurons are key in long-term energy balance, while brainstem POMC neurons influence rapid feeding control.
• POMC peptide processing and function show variations across vertebrate evolution.
• Gnathostomes possess an infundibular POMC neuronal group, but details on its evolution and function are incomplete.

Conclusions:

• POMC neurons and their derived peptides are vital regulators of energy balance and analgesia throughout vertebrate evolution.
• Further research is needed to elucidate the evolutionary trajectory and diverse functions of POMC systems, especially in non-mammalian vertebrates.
• Understanding POMC neuron diversity is essential for comprehending complex physiological processes like feeding and nutrient signaling.