Pituitary adenylate cyclase activating polypeptide expression in sensory neurons

Area of Science:

• Neuroscience
• Molecular Biology
• Neuropeptide Research

Background:

• Pituitary adenylate cyclase activating polypeptide (PACAP) is a VIP-like peptide.
• PACAP-like immunoreactivity has been detected in rat sensory ganglia neurons.

Purpose of the Study:

• To determine if PACAP is synthesized in sensory ganglia neurons.
• To compare PACAP expression with calcitonin gene-related peptide (CGRP) expression.

Main Methods:

• In situ hybridization using 35S-labelled oligonucleotide probes for PACAP mRNA.
• Comparison with radiolabelled CGRP oligonucleotide probes.

Main Results:

• PACAP mRNA was detected in small to medium-sized neurons in trigeminal and dorsal root ganglia.
• PACAP-expressing cells constituted approximately 10% of dorsal root ganglion neurons, compared to 46% for CGRP.
• PACAP expression was observed in a subpopulation of CGRP-expressing cells.

Conclusions:

• PACAP is synthesized in a subpopulation of rat sensory ganglia neurons.
• PACAP's known effects on vasodilation, edema, and nociception may be physiological roles.
• PACAP may be involved in neurogenic inflammation and pain modulation.