Neuropeptide Y Y1 receptor effects on pulpal nociceptors.

Neuropeptide Y (NPY) is an important modulatory neuropeptide that regulates several physiological systems, including the activity of sensory neurons. We evaluated whether activation of the NPY Y1 receptor could modulate the activity of capsaicin-sensitive nociceptors in trigeminal ganglia and dental pulp. We tested this hypothesis by measuring capsaicin-stimulated calcitonin gene-related peptide release (CGRP) as a measure of nociceptor activity. Capsaicin-evoked CGRP release was inhibited by 50% (p < 0.05) in trigeminal ganglia and by 26% (p < 0.05) in dental pulp when tissues were pre-treated with [Leu(31),Pro(34)]NPY. The Y1 receptor was found to co-localize with the capsaicin receptor TRPV1 in trigeminal ganglia. These results demonstrate that activation of the Y1 receptor results in the inhibition of the activity of capsaicin-sensitive nociceptors in the trigeminal ganglia and dental pulp. These findings are relevant to the physiological modulation of dental nociceptors by endogenous NPY and demonstrate an important novel analgesic target for the treatment of dental pain.