Autoradiographic localization of 125I[Tyr14]orphanin FQ/nociceptin and 125I[Tyr10]orphanin FQ/nociceptin(1-11) binding sites in rat brain Journal Article

  

Authors:	Letchworth, S. R.; Mathis, J. P.; Rossi, G. C.; Bodnar, R. J.; Pasternak, G. W.
Article Title:	Autoradiographic localization of 125I[Tyr14]orphanin FQ/nociceptin and 125I[Tyr10]orphanin FQ/nociceptin(1-11) binding sites in rat brain
Abstract:	The endogenous ligand for the orphan opioid receptor, orphanin FQ/nociceptin (OFQ), has recently been characterized. The OFQ peptide sequence contains paired basic amino acids, suggesting the possibility of posttranslational processing to a peptide containing the first 11 amino acids of the OFQ peptide. This peptide has been reported in the brain and it has a unique pharmacology. In the present study, we compared the autoradiographic distribution of 125[Tyr14]OFQ and 125I[Tyr10]OFQ(1-11) in coronal rat brain sections. Nonspecific binding Was defined with unlabeled OFQ or OFQ(1-11), respectively. Both radioligands demonstrated high levels of specific binding (>95% of total binding), with no appreciable binding in white matter areas with either ligand, 125I[Tyr14]OFQ binding was widely distributed throughout the rat brain. In contrast, 125I[Tyr10]OFQ(1-11) binding was more restricted. The highest 125I[Tyr14]OFQ binding levels measured in this study were found in the locus coeruleus, an area which contained very low 125I[Tyr10]OFQ(1-11) binding. Both ligands labeled the cortex, hippocampus and amygdala. In the thalamus, 125I[Tyr14]OFQ binding was prominent in most nuclei, whereas 125I[Tyr10]OFQ(1-11) binding was restricted to the midline thalamus. 125I[Tyr14]OFQ binding was heavy in the suprachiasmatic hypothalamus, and moderate in other hypothalamic nuclei. 125I[Tyr10]OFQ(1-11) binding in the hypothalamus, however, was present mainly in the ventromedial hypothalamic nucleus. Lower binding levels of both ligands were found in the caudate putamen. The distinct autoradiographic patterns of these two ligands are consistent with different binding sites, which might help explain their different functional activities. (C) 2000 Wiley-Liss, Inc.
Keywords:	nonhuman; protein localization; animal; cytology; metabolism; animals; animal tissue; protein binding; tyrosine; physiology; radioactive iodine; tissue distribution; iodine radioisotopes; brain; peptide fragments; peptide fragment; locus ceruleus; rat; binding site; binding sites; rats; mesencephalon; rats, sprague-dawley; brain mapping; rhombencephalon; autoradiography; sprague dawley rat; brain level; hippocampus; telencephalon; opioid peptides; thalamus; nociceptin; opiate peptide; brain chemistry; amygdaloid nucleus; metencephalon; radioassay; radioligand assay; diencephalon; priority journal; article; ofq; ofq (1-17); ofq(1-11)
Journal Title:	Journal of Comparative Neurology
Volume:	423
Issue:	2
ISSN:	0021-9967
Publisher:	John Wiley & Sons
Date Published:	2000-07-24
Start Page:	319
End Page:	329
Language:	English
DOI:	10.1002/1096-9861(20000724)423:2<319::aid-cne9>3.0.co;2-c
PUBMED:	10867661
PROVIDER:	scopus
DOI/URL:	http://www.scopus.com/inward/record.url?eid=2-s2.0-0034709770&partnerID=40&md5=b6a6d1a03585284874b42a0ca15f3d11
Notes:	Export Date: 18 November 2015 -- Source: Scopus

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