Brain peptide YY receptors: highly conserved characteristics throughout vertebrate evolution

Area of Science:

• Neuroscience
• Comparative Biology
• Biochemistry

Background:

• Peptide YY (PYY) receptors are widely distributed in mammalian brains.
• Previous studies identified a 50,000 mol wt PYY receptor in porcine hippocampus.
• Neuropeptide Y (NPY) is a related peptide with similar receptor interactions.

Purpose of the Study:

• To characterize PYY and NPY receptor interactions and structures across diverse vertebrate species.
• To compare receptor properties between mammals, birds, reptiles, amphibians, and fish.
• To investigate evolutionary conservation and potential functional divergence of these receptors.

Main Methods:

• Equilibrium binding analysis using radiolabeled peptides.
• Scatchard plot analysis to determine binding affinities.
• Affinity cross-linking with disuccinimidyl suberate followed by SDS-PAGE.

Main Results:

• PYY and NPY receptors exhibit conserved pharmacological profiles and molecular weights (approx. 50,000 mol wt) across most vertebrates, including mammals, reptiles, amphibians, and fish.
• Chicken brain receptors showed distinct high-affinity binding for pancreatic polypeptide (PP) family peptides, unlike other species.
• A higher molecular weight (67,000 mol wt) PYY receptor was identified in chicken brain.
• NPY receptors were identified as monomeric proteins of 50,000-55,000 mol wt in mammals and fish.

Conclusions:

• Brain PYY and NPY receptors are highly conserved evolutionarily (over 400 million years) in terms of pharmacology and structure.
• The unique characteristics of chicken brain receptors suggest a potential divergence in their function compared to other vertebrates.
• These findings provide insights into the evolutionary history and functional significance of PYY and NPY signaling pathways.