title: Nociceptin/orphanin FQ and stress regulate synaptophysin expression in the rat fundic and colonic mucosa.
abstract: Nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the N/OFQ peptide (NOP) receptor, is a neuropeptide regulating gastrointestinal functions. The present study investigated the influence of acute cold-restraint stress and of short- and long-lasting peripheral infusion of N/OFQ on the level of synaptophysin, an exocytotic protein involved in neural plasticity. Exposure to cold-restraint stress for 3h or subcutaneous infusion of N/OFQ, 1 μg/kg/h for 4h, induced a significant increase of the area of synaptophysin-immunoreactive nerve fibers in the fundic mucosa, while prolonged subcutaneous infusion of N/OFQ, 1 μg/kg/h for 52 h and for 14 days, did not modify the synaptophysin-immunostained fibers. In the colonic mucosa stress exposure and subcutaneous infusion of N/OFQ, at any time point considered, had no significant effect on the area of synaptophysin-immunoreactive nerve fibers. Synaptophysin immunoreactive nerve fibers were decreased in knockout rats for the NOP receptor gene both in the fundic and colonic mucosa. Synaptophysin-immunoreactivity was demonstrated in cells located in the basal portion of the fundic mucosa. Our study is the first to show that the N/OFQ/NOP receptor system influences the expression of synaptophysin and hence the process of exocytosis both in nerve terminals and in cells.
authors.affiliation: Department of Biomedical, Biotechnological and Translational Sciences, University of Parma, Parma, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Grandi
authors.affiliation: Department of Biomedical, Biotechnological and Translational Sciences, University of Parma, Parma, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Becchi
authors.affiliation: Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, Ferrara, Italy.
authors.forename: Remo
authors.initials: R
authors.lastname: Guerrini
authors.affiliation: Department of Medical Sciences, Section of Pharmacology, University of Ferrara, Ferrara, Italy; National Institute of Neuroscience, University of Ferrara, Ferrara, Italy.
authors.forename: Girolamo
authors.initials: G
authors.lastname: Calò
authors.affiliation: Department of Neuroscience, University of Parma, Parma, Italy. Electronic address: giuseppina.morini@unipr.it.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Morini
mesh_terms: D000818:Animals; D005089:Exocytosis / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D018847:Opioid Peptides / Q000378:metabolism; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology*; D016708:Synaptophysin / Q000378:metabolism*; D014665:Vasodilator Agents / Q000378:metabolism*; D000094942:Nociceptin Receptor; D000097629:Nociceptin
chemical_list: D018847:Opioid Peptides; D011957:Receptors, Opioid; D016708:Synaptophysin; D014665:Vasodilator Agents; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C569016:Syp protein, rat; C000722285:Oprl1 protein, rat
keywords: Cold-restraint stress; Distal colon; Gastric fundus; Knockout rats for the NOP receptor gene; Mucosa; Nerve fibers; Nociceptin/orphanin FQ; Rat; Synaptophysin