Distribution of Orphanin FQ/Nociceptin and its receptor in the nervous system

Distribution of Orphanin FQ/Nociceptin and its receptor in the nervous system

Field: Neurotransmitters and receptors

Authors: Pettersson, Lina
Sundler, Frank
Danielsen, Nils

Address of presenting
author: Lina Pettersson
Neuroendokrin Cellbiologi
Fysiologi och Neurovetenskap
EA-blocket; 5:e vån.
Universitetssjukhuset
221 85 Lund

E-mail: lina.pettersson@mphy.lu.se

Phone: 046-17 77 15

Fax: 046-17 77 20

Text of abstract: The neuropeptide Orphanin FQ/Nociceptin (OFQ/N) and its receptor, opioid receptor like (ORL1) receptor, are suggested to modulate sensory perception in general, and pain perception in particular. Depending on the circumstances, OFQ/N can produce either hyperalgesia or analgesia. In the present study the sites of synthesis and distribution of OFQ/N and its receptor were analysed in the rat sensory nervous system and some selected parts of the CNS using immunohistochemistry, in situ hybridization and ligand binding. A dense distribution of OFQ/N immunoreactive fibers was found in the superficial layer of the dorsal horn of the spinal cord. Occasional radiating fibers occurred in lamina III-VI and immunoreactivity was also seen in and around motor neuron cell bodies in the ventral horn. Immunolabeling was found in the hippocampus, a positive reference tissue. With the use of radiolabeled oligoprobes, OFQ/N- and ORL1 mRNA was detected in dorsal- and ventral horn neurons and also in neurons around the central canal of the spinal cord. In dorsal root ganglia (DRG) a scattered expression was found in cells of all sizes, which has to be interpreted with some caution since it was not totally abolished in the control slides incubated with excess nonlabeled probe. ¹²⁵I-[Tyr¹]-OFQ/N binding was seen in hypothalamus, spinal cord grey substance and weakly in DRG. This study has increased our knowledge of the distribution of OFQ/N and its receptor and the study has also included an evaluation of antibodies, probes and protocol procedures which will be applied in future studies regarding OFQ/N and ORL1. If OFQ/N has a nociceptive effect in the periphery, as well as centrally, the finding of the source of OFQ/N may have implications for the understanding of pain.

Keywords: Orphanin FQ/nociceptin, ORL1 receptor, neuropeptide, pain, dorsal horn

	Distribution of Orphanin FQ/Nociceptin and its receptor in the nervous system
Field:	Neurotransmitters and receptors
Authors:	Pettersson, Lina Sundler, Frank Danielsen, Nils
Address of presenting author:	Lina Pettersson Neuroendokrin Cellbiologi Fysiologi och Neurovetenskap EA-blocket; 5:e vån. Universitetssjukhuset 221 85 Lund
E-mail:	lina.pettersson@mphy.lu.se
Phone:	046-17 77 15
Fax:	046-17 77 20
Text of abstract:	The neuropeptide Orphanin FQ/Nociceptin (OFQ/N) and its receptor, opioid receptor like (ORL1) receptor, are suggested to modulate sensory perception in general, and pain perception in particular. Depending on the circumstances, OFQ/N can produce either hyperalgesia or analgesia. In the present study the sites of synthesis and distribution of OFQ/N and its receptor were analysed in the rat sensory nervous system and some selected parts of the CNS using immunohistochemistry, in situ hybridization and ligand binding. A dense distribution of OFQ/N immunoreactive fibers was found in the superficial layer of the dorsal horn of the spinal cord. Occasional radiating fibers occurred in lamina III-VI and immunoreactivity was also seen in and around motor neuron cell bodies in the ventral horn. Immunolabeling was found in the hippocampus, a positive reference tissue. With the use of radiolabeled oligoprobes, OFQ/N- and ORL1 mRNA was detected in dorsal- and ventral horn neurons and also in neurons around the central canal of the spinal cord. In dorsal root ganglia (DRG) a scattered expression was found in cells of all sizes, which has to be interpreted with some caution since it was not totally abolished in the control slides incubated with excess nonlabeled probe. ¹²⁵I-[Tyr¹]-OFQ/N binding was seen in hypothalamus, spinal cord grey substance and weakly in DRG. This study has increased our knowledge of the distribution of OFQ/N and its receptor and the study has also included an evaluation of antibodies, probes and protocol procedures which will be applied in future studies regarding OFQ/N and ORL1. If OFQ/N has a nociceptive effect in the periphery, as well as centrally, the finding of the source of OFQ/N may have implications for the understanding of pain.

Keywords:	Orphanin FQ/nociceptin, ORL1 receptor, neuropeptide, pain, dorsal horn

Index

Created 2000-03-13

Department of Physiological Sciences, Lund University

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