Although pulpal neuropeptides such as calcitonin gene-related peptide and substance P may mediate neurogenic inflammation, little is known about the regulation of neuropeptide release from dental pulp. This article describes an in vitro method for superfusing dental pulp which permits the study of mechanisms regulating the release of immunoreactive CGRP (iCGRP). Tissue extracts from bovine dental pulp dilute in parallel to authentic calcitonin generelated peptide and substance P peptide standards when assayed by radioimmunoassay. Pulpal levels of iCGRP were 17-fold greater than levels of immunoreactive substance P. Administration of a potassium pulse evoked a significant release of iCGRP from dental pulp (155 ± 21 fmol/g/9 min) as compared with iCGRP spontaneously released from concurrent control chambers (18 ± 11 fmol/g/9 min). The in vitro superfusion of pulp tissue may serve as a useful method for identifying peripherally acting drugs which modulate nociceptor secretory activity and for determining their mechanisms of action.
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