Nociceptin-induced histamine release in the brain: comparison with compound 48/80- and substance P-induced amine secretions.

摘要

Orphanin FQ/Nociceptin (NC), a heptadecapeptide, belongs to the endogenous opioid-like family, but it exerts functionally distinct actions. It has been characterised as an inhibitory peptide with respect to its actions on aminergic systems, including the serotoninergic (5-HT) system [1]. Previously we have demonstrated increased histamine (HA) levels in rat cerebrospinal fluid (CSF), hypothalamus and hippocampus after intracerebroventricular (i.c.v.) NC administration, with a maximal effect within 2-3 h [2]. To examine the possible role of mast cells (Me) in this action, we completed a study of parallel measurements of CSF and plasma HA and 5-HT contents, the chief constituents of Me secretion, after a single i.c.v. injection of NC. We also compared the effects of NC with those of compound 48/80 (C48/80), the mast cell degranulating agent (deemed selective for Me stimulation and modulating blood brain barrier (BBB) permeability), and Substance P (SP), the neuroactive Me secretagogue. Additionally, we examined the susceptibility of the responses to disodium cromoglycate (Cromolyn), a known stabiliser of Me.