title: Localisation of the neuropeptide PACAP and its receptors in the rat parathyroid and thyroid glands.
abstract: PACAP (pituitary adenylate cyclase activating polypeptide) is widely distributed neuropeptide acting via three subtypes of receptors, PAC(1), VPAC(1) and VPAC(2). Here we examined the localisation and nature of PACAP-immunoreactive nerves in the rat thyroid and parathyroid glands and defined the distribution of PAC(1), VPAC(1) and VPAC(2) receptor mRNA's. In the parathyroid gland a large number of nerve fibres displaying PACAP-immunoreactivity were distributed beneath the capsule, around blood vessels and close to glandular cells. Most of the PACAP-nerves were sensory, since they co-stored CGRP (calcitonin-gene-related peptide) and were sensitive to capsaicin-treatment. mRNA's for PAC(1) and VPAC(2) receptors occurred in the parathyroid gland, mainly located in the glandular cells. In the thyroid gland PACAP-immunoreactive nerve fibres were associated with blood vessels, thyroid follicles and parafollicular C-cells. A high degree of co-existence between PACAP and VIP (vasoactive intestinal polypeptide) was observed in the intrathyroid nerve fibres and cell bodies of the thyroid ganglion indicating a common origin for the two peptides. A minor population of PACAP-immunoreactive nerve fibres with relation to blood vessels co-stored NPY (neuropeptide Y), whereas only a few fibres co-stored CGRP. PAC(1) and VPAC(1) receptor mRNA's occurred in follicular cells and blood vessels, whereas the expression of the VPAC(2) receptor was low. The findings suggest that PACAP plays a role in the regulation of parathyroid and thyroid blood flow and hormone secretion.
authors.affiliation: Department of Clinical Biochemistry, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen NV, Denmark. jfah0001@bbh.regionh.dk
authors.forename: Jan
authors.initials: J
authors.lastname: Fahrenkrug
authors.forename: Jens
authors.initials: J
authors.lastname: Hannibal
mesh_terms: D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism; D010280:Parathyroid Glands / Q000378:metabolism*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D013961:Thyroid Gland / Q000378:metabolism*
chemical_list: D009478:Neuropeptide Y; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide