Expression of orphanin FQ and the opioid receptor-like (ORL1) receptor in the developing human and rat brain

https://doi.org/10.1016/S0891-0618(01)00135-1Get rights and content

Abstract

The orphanin peptide system, although structurally similar to the endogenous opioid family of peptides and receptors, has been established as a distinct neurochemical entity. The distribution of the opioid receptor-like (ORL1) receptor and its endogenous ligand orphanin FQ (OFQ) in the central nervous system of the adult rat has been recently reported, and although diffusely disseminated throughout the brain, this neuropeptide system is particularly expressed within stress and pain circuitry. Little is known concerning the normal expression of the orphanin system during gestation, nor how opiate or stress exposure may influence its development. Using in situ hybridization techniques, the present study was undertaken to determine the normal pattern of expression of ORL1 mRNA in the human and rat brain at various developmental stages. Rat embryos, postnatal rat brains and postmortem human brains were collected, frozen and cut into 15 μm coronal sections. In situ hybridization was performed using riboprobes generated from cDNA containing representative human and rat ORL1 and OFQ sequences. Both ORL1 and OFQ mRNA is detected as early as E12 in the cortical plate, basal forebrain, brainstem and spinal cord. Expression for both ORL1 and OFQ is strongest during the early postnatal period, remaining strong in the spinal cord, brainstem, ventral forebrain, and neocortex into the adult. Human ORL1 and OFQ expression is observed at 16 weeks gestation, remaining relatively unchanged up to 36 weeks. The influence of early orphanin expression on maturation of stress and pain circuitry in the developing brain remains unknown.

Introduction

The opioid receptor-like receptor (ORL1), a seven transmembrane member of the G-protein family of receptors, shares significant amino acid homology with the opioid receptors (Bunzow et al., 1994, Chen et al., 1994, Fukuda et al., 1994, Marchese et al., 1994, Mollereau et al., 1994, Wick et al., 1994, Wang et al., 1994, Lachowicz et al., 1995). In spite of these similarities, opioid peptides and opiate alkaloids have little affinity for the orphanin receptor (Bunzow et al., 1994, Chen et al., 1994, Fukuda et al., 1994, Lachowicz et al., 1995, Mollereau et al., 1994, Wick et al., 1994, Ma et al., 1997, Nicholson et al., 1998). Functional studies of ORL1 have shown it to exclusively bind an endogenous ligand, a heptadecapeptide referred to as nociceptin or orphanin FQ (OFQ). Although OFQ demonstrates high affinity binding to ORL1 and inhibits cAMP formation similar to endogenous opioid peptides (Meunier et al., 1995, Reinscheid et al., 1995, Dooley and Houghten, 1996, Reinscheid et al., 1996, Saito et al., 1995, Saito et al., 1996, Saito et al., 1997, Shimohigashi et al., 1996, Ardati et al., 1997, Butour et al., 1997, Civelli et al., 1997, Guerrini et al., 1997), it demonstrates no binding affinity for endogenous opioid receptors.

Orphanin FQ has an amino acid sequence strikingly similar to the endogenous opioid peptide dynorphin A1–17 and is derived from a larger precursor molecule referred to as preproorphanin, which itself shares structural homology to the opioid precursor prodynorphin (Houtani et al., 1996, Mollereau et al., 1996, Nothacker et al., 1996, Pan et al., 1996). Recent studies have demonstrated that, similar to endogenous opioid precursors, preproorphanin contains additional neuropeptides that may be biologically active (Okuda-Ashitaka et al., 1998, Rossi et al., 1998, Hiramatsu and Inoue, 1999, Xu et al., 1999, Yamamoto et al., 1999, Zhao et al., 1999, Nakano et al., 2000), suggesting a coordinated mechanism of evolution that has separated the orphanin FQ and opioid systems (Reinscheid et al., 1998, Danielson and Dores, 1999).

Functionally, numerous specific effects have been demonstrated by the binding of OFQ to the ORL1 receptor. At the cellular level ORL1 activation leads to inhibition of cAMP formation, stimulation of protein kinase C, and neuronal Ca2+ and K+ conductance changes. Systemic and central nervous system (CNS) infusions of OFQ have been shown to modulate several complex physiologic functions and behaviors, including pituitary function, cardiovascular control, sodium balance, allodynia and nociception, feeding, learning, locomotion, stress response and sexual behavior (for reviews; Civelli et al., 1998, Darland et al., 1998, Harrison and Grandy, 2000, Mollereau and Mouledous, 2000).

Several studies have confirmed an extensive distribution of the orphanin system throughout the central nervous system. General descriptions of [3H]orphanin receptor binding in the mouse (Florin et al., 1997), 125I-labeled orphanin binding in the rat and human hypothalamus (Makman et al., 1997), and preproOFQ and ORL1 mRNA distribution in the developing mouse brain (Ikeda et al., 1998) have been reported. Detailed descriptions of the distribution of preproorphanin and ORL1 mRNA, OFQ peptide immunoreactivity, and 125I-OFQ binding to the ORL1 receptor in the adult rat CNS has also been reported (Neal et al., 1999a, Neal et al., 1999b). In these studies, OFQ and ORL1 were shown to be widely distributed throughout the brain and spinal cord, with prominent representation in stress and pain circuitry.

In spite of detailed anatomical investigations focusing on OFQ and its relation to ORL1, no anatomical report to date has analyzed the expression of the orphanin system during gestational or early postnatal development. Equally lacking is an analysis of OFQ and ORL1 distribution in the human central nervous system. A knowledge of the distribution of the orphanin system during development, in human as well as the rodent, is crucial in understanding what role, if any, orphanin may play in the evolution of stress and pain circuitry. Exposure to stress, both prenatal (Weinstock, 1997, Williams et al., 1999) and postnatal (Suchecki et al., 1995, Johnson et al., 1996, Meaney et al., 1996, Sutanto et al., 1996, Vázquez et al., 1996, Williams et al., 1999), has been shown to have long-term effects on the development and function of the limbic–hypothalamic–pituitary adrenal axis in the human, primate and rat. Although exposure to morphine in the neonatal period does not seem to have any adverse effects on intelligence, motor function, or behaviour (MacGregor et al., 1998), exposure to pain and exogenous opiates does appear to have a long-term effect on not only tolerance to opioid peptides, but also to painful stimuli (Rots et al., 1996, Anand et al., 1999, Whitfield and Grunau, 2000). Moreover, not only is OFQ and ORL1 distinctly distributed throughout this pain and stress neurocircuitry, there is a significant amount of behavioral data implicating OFQ in the stress response (Jenck et al., 1997, Griebel et al., 1999, Koster et al., 1999, Jenck et al., 2000, Martin-Fardon et al., 2000) and pain perception (Grisel et al., 1996, Mogil et al., 1996a, Mogil et al., 1996b, Rossi et al., 1996, Rossi et al., 1997, Stanfa et al., 1996, Xu et al., 1996, Dawson-Basoa and Gintzler, 1997, Hara et al., 1997, Heinricher et al., 1997, King et al., 1997, Liebel et al., 1997, Minami et al., 1997, Morgan et al., 1997, Nishi et al., 1997, Tian et al., 1997a, Tian et al., 1997b, Yamamoto et al., 1997, Yamamoto et al., 1999, Zhu et al., 1997, Kolesnikov and Pasternak, 1997, Mogil et al., 1999, Pan et al., 2000).

Given the high likelihood for an important role of orphanin in stress and pain systems, and the profound influence that prenatal or early postnatal stress and/or pain exposure can have on the development of these systems, it is important to better understand the ontological expression of OFQ and its receptor in the brain. We present results of an ontological study examining the expression of preproorphanin and ORL1 mRNA in the rat brain at various gestational ages, as well as ORL1 and OFQ mRNA expression in select regions of the human brain tissue at various gestational ages during the second and third trimester.

Section snippets

Animals

Time-pregnant adult female Sprague–Dawley rats were obtained from Charles River at various gestational ages. Prior to sacrifice, handling and use of all animals strictly conformed to NIH guidelines. Additionally, protocols for animal use in this study were approved by the university unit for lab animal medicine (ULAM) at the University of Michigan Medical Center.

Rat tissue

Age of gestation of pregnant females was provided by Charles River, and fetal age was assigned as embryonic (E) days 12–22 prior to

Tissue fixation

In our hands, the distribution of preproorphanin and ORL1 mRNA expression in adult rat tissue is identical to what has been observed using fresh frozen tissue in previous studies (Neal et al., 1999a, Neal et al., 1999b). Initial studies with fresh frozen developmental rat tissue also demonstrated no difference in mRNA expression between Zamboni-fixed and fresh frozen tissue. However, integrity of embryonic and early postnatal rat tissue was superior in previously fixed tissue after exposure to

Discussion

Several studies have reported a widespread distribution of OFQ and the ORL1 receptor in the CNS of several species. Following the sequencing of the primary structure of the rat and human OFQ precursor, the general tissue distribution of preproorphanin mRNA was reported for the rat and mouse (Houtani et al., 1996, Mollereau et al., 1996, Nothacker et al., 1996, Pan et al., 1996), as well as the primate hypothalamus (Quigley et al., 1998). Orphanin FQ immunoreactivity has also been described in

Conclusion

In addition to the stress of critical illness, premature neonates are often exposed to multiple stressors during their stay in the neonatal intensive care unit, including handling, cold, pain, light and noise stress to name a few. As part of their management, most of these infants are also exposed to one or more neuroactive agents, such as benzodiazepines, glucocorticoids and opiates. These environmental exposures occur during a critical phase of development in the central nervous system.

Acknowledgements

Fetal human brain tissue used in this study was generously provided by Mason Barr, MD, Department of Pediatrics, Genetics Division. We are grateful for his generosity. Tissue was also obtained from the University of Miami Brain and Tissue Bank for Developmental Disorders through NICHD contract no. NO1-HD-8-3284. We also wish to thank Sharon Burke, Lisa Bain and James Stewart for their superb technical assistance. This work was supported by a Robert Wood Johnson Foundation Fellowship to CRNJ

References (107)

  • K. Fukuda et al.

    cDNA cloning and regional distribution of a novel member of the opioid receptor family

    FEBS Lett.

    (1994)
  • G. Griebel et al.

    Orphanin FQ, a novel neuropeptide with anti-stress-like activity

    Brain Res.

    (1999)
  • L.M. Harrison et al.

    Opiate modulating properties of nociceptin/orphanin FQ

    Peptides.

    (2000)
  • M. Hiramatsu et al.

    Effects of nocistatin on nociceptin-induced impairment of learning and memory in mice

    Eur. J. Pharmacol.

    (1999)
  • T. Houtani et al.

    Structure and distribution of the OFQ precursor

    Biochem. Biophys. Res. Commun.

    (1996)
  • M.A. King et al.

    Spinal analgesic activity of orphanin FQ and its fragments

    Neurosci. Lett.

    (1997)
  • C.C. Lai et al.

    Nociceptin-like immunoreactivity in the dorsal horn and inhibition of substantia gelatinosa neurons

    Neuroscience

    (1997)
  • L. Ma et al.

    Functional expression, activation and desensitization of opioid receptor-like receptor ORL1 in neuroblastoma x glioma NG108-15 hybrid cells

    FEBS Lett.

    (1997)
  • M.H. Makman et al.

    Presence and characterization of orphanin FQ receptor binding in adult rat and human fetal hypothalamus

    Brain Res.

    (1997)
  • A. Marchese et al.

    Cloning of human genes encoding novel G protein-coupled receptors

    Genomics.

    (1994)
  • J.S. Mogil et al.

    Functional antagonism of mu-, delta- and kappa-opioid antinociception by orphanin FQ

    Neurosci. Lett.

    (1996)
  • J.S. Mogil et al.

    Orphanin FQ is a functional anti-opioid peptide

    Neuroscience

    (1996)
  • J.S. Mogil et al.

    Strain-dependent effects of supraspinal orphanin FQ on thermal nociceptive sensitivity in mice

    Neurosci. Lett.

    (1999)
  • C. Mollereau et al.

    Tissue distribution of the opioid receptor-like (ORL1) receptor

    Peptides

    (2000)
  • C. Mollereau et al.

    ORL1, a novel member of the opioid receptor family. Cloning, functional expression and localization

    FEBS Lett.

    (1994)
  • Z. Pan et al.

    A cellular mechanism for the bi-directional pain-modulating actions of orphanin FQ/nociceptin

    Neuron.

    (2000)
  • D.I. Quigley et al.

    Orphanin FQ is the major OFQ 1-17-containing peptide produced in the rodent and monkey hypothalamus

    Peptides

    (1998)
  • R.K. Reinscheid et al.

    Structure-activity relationship studies on the novel neuropeptide orphanin FQ

    J. Biol. Chem.

    (1996)
  • R.K. Reinscheid et al.

    Structures that delineate OFQ and dynorphin A pharmacologic selectivities

    J. Biol. Chem.

    (1998)
  • G.C. Rossi et al.

    Naloxone sensitive orphanin FQ-induced analgesia in mice

    Eur. J. Pharmacol.

    (1996)
  • Y. Saito et al.

    N23K, a gene transiently up-regulated during neural differentiation, encodes a precursor protein for a newly identified neuropeptide nociceptin

    Biochem. Biophys. Res. Commun.

    (1995)
  • Y. Saito et al.

    Molecular cloning and characterization of a novel form of neuropeptide gene as a developmentally regulated molecule

    J. Biol. Chem.

    (1996)
  • R. Schuligoi et al.

    Determination of nociceptin-like immunoreactivity in the rat dorsal spinal cord

    Neurosci. Lett.

    (1997)
  • Y. Shimohigashi et al.

    Sensitivity of opioid receptor-like receptor for chemical modification on nociceptin, a naturally occurring nociceptive peptide

    J. Biol. Chem.

    (1996)
  • D. Suchecki et al.

    Activation and inhibition of the hypothalamic–pituitary–adrenal axis in the infant rat: effects of maternal deprivation

    Psychoneuroendo.

    (1995)
  • W. Sutanto et al.

    Long-term effects of neonatal maternal deprivation and ACTH on hippocampal mineralocorticoid and glucocorticoid receptors

    Dev. Brain Res.

    (1996)
  • D.M. Vázquez et al.

    Regulation of mineralocorticoid and glucocorticoid receptor mRNAs in the hippocampus of the maternally deprived rat

    Brain Res.

    (1996)
  • J.B. Wang et al.

    cDNA cloning of an orphan opiate receptor gene family member and its splice variant

    FEBS Lett.

    (1994)
  • M. Weinstock

    Does prenatal stress impair coping and regulation of hypothalamic–pituitary–adrenal axis?

    Neurosci. Biobehav. Rev.

    (1997)
  • M.F. Whitfield et al.

    Behavior, pain perception, and the extremely low-birth weight survivor

    Clin. Perinatol.

    (2000)
  • M.T. Williams et al.

    Changes in hormonal concentrations of pregnant rats and their fetuses following multiple exposures to a stressor during the third trimester

    Neurotoxicol. Teratol.

    (1999)
  • M.J. Wick et al.

    Isolation of a novel cDNA encoding a putative membrane receptor with high homology to the cloned mu, delta, and kappa receptors opioid

    Brain Res. Mol. Brain Res.

    (1994)
  • J. Altman et al.

    Atlas of Prenatal Rat Brain Development

    (1995)
  • K.J. Anand et al.

    Analgesia and sedation in preterm neonates who require ventilatory support: results from the NOPAIN trial

    Arch. Pediatr. Adolesc. Med.

    (1999)
  • B. Anton et al.

    Immunohistochemical localization of ORL-1 in the central nervous system of the rat

    J. Comp. Neurol.

    (1996)
  • A. Ardati et al.

    Interaction of [3H]orphanin FQ and 125I-Tyr14-orphanin FQ with the orphanin FQ receptor: kinetics and modulation by cations and guanine nucleotides

    Mol. Pharmacol.

    (1997)
  • S.A. Bayer et al.

    Neurogenesis and neuronal migration

  • S.A. Bayer et al.

    Principals of neurogenesis, neuronal migration and neural circuit formation

  • C. Brana et al.

    Ontogeny of the striatal neurons expressing neuropeptide genes in the human fetus and neonate

    J. Comp. Neurol.

    (1995)
  • O. Civelli et al.

    Orphan receptors and their natural ligands

    J. Recept. Signal Transduct. Res.

    (1997)
  • Cited by (63)

    • Pain in sickle cell disease: current and potential translational therapies

      2021, Translational Research
      Citation Excerpt :

      Nociceptin opioid receptor (NOPR) and its endogenous ligand nociceptin/orphanin FQ (N/OFQ) belong to the opioid receptor (OR) family and are involved in pain signaling. NOPRs are found centrally in the DRG and spinal cord.129,130 Neuropeptide release from mast cells was found to be attenuated by N/OFQ.131

    • Operant self-administration of ethanol in infant rats

      2015, Physiology and Behavior
      Citation Excerpt :

      Mu, delta, and kappa receptors follow different patterns of ontogenetic development; yet all three are functional by the second week of postnatal life [117]. The NOP receptor is expressed very early in life: it is detected as early as gestational day 12 in the rat and is observed at 16 weeks of gestation in humans [68]. After the first two weeks of postnatal life in the rat, NOP mRNA expression and distribution simulate those observed in the adult brain.

    View all citing articles on Scopus
    View full text