Calcitonin gene-related peptide release from intact isolated dorsal root and trigeminal ganglia

Neuropeptides like calcitonin gene-related peptide (CGRP) and substance P are found in significant proportions of primary afferent neurons. Release of these neuropeptides as well as prostaglandin E2 is an approved index for the activation of these primary afferents. Previous studies have used cultures of enzyme-treated and mechanically dissociated primary afferent neurons, fresh tissue slices or cubes. In the present study we demonstrate CGRP and prostaglandin E2 release from intact isolated dorsal root and trigeminal ganglia. Stimulation with noxious heat, low pH, inflammatory mediators and high potassium concentration increased CGRP release. In conclusion, neuropeptide release from intact isolated ganglia is a reliable method to study the responsiveness of sensory neurons in situ in comparison with neuronal cell cultures.