Messenger molecules and receptor mRNA in the human trigeminal ganglion

The presence and distribution of neuromessenger molecules and receptor mRNA in human trigeminal ganglion was studied with immunocytochemical, in situ hybridisation and RT-PCR techniques. Immunofluorescence staining revealed t hat calcitonin gene-related peptide (CGRP) immunoreactive (-ir) neurons occ urred in high numbers, constituting 36-40% of all nerve cell bodies in the ganglion. Accordingly, in situ hybridisation demonstrated CGRP mRNA in a la rge portion of the trigeminal neurons. A small number of the nerve cell bod ies showed substance P (SP)-ir, (18%), nitric oxide synthase (NOS)-ir (15%) , and pituitary adenylate cyclase activating peptide (PACAP)-ir (20%). Doub le immunostaining revealed that only few CGRP-ir neurons also were NOS-ir ( less than 5%). The C-terminal flanking peptide of neuropeptide Y, C-PON, wa s not visible in any of the nerve cell bodies studied. Agarose gel electrop horesis of the RT-PCR products from the ganglia demonstrated the presence o f mRNA corresponding to CGRP(1), NPY Y-1 and Y-2, and VIP1 receptors. These results suggest both sympathetic and parasympathetic influence on the acti vity in the trigeminal ganglion. (C) 1999 Published by Elsevier Science B.V . All rights reserved.