nocistatin and Pain

A neuropeptide nociceptin or orphanin FQ (N/OFQ) is an endogenous ligand for the orphan opioid receptor-like receptor. During studies on the analysis of the precursor of N/OFQ, we identified a novel neuropeptide produced from the same precursor and named it "nocistatin (NST)". Intrathecal (i.t.) administration of N/OFQ induces pain responses including touch-evoked allodynia and thermal hyperalgesia, and simultaneous administration of NST blocks the allodynia and hyperalgesia induced by N/OFQ. In the years since these discoveries, N/OFQ has been shown to be involved in a wide range of pharmacological activities, such as relaying pain perception in peripheral tissues, to the central nervous system, and NST was shown to have opposite effects on various central functions evoked by N/OFQ. Pharmacological characterization using various neurotransmitter agents, agonists, antagonists and knockout mice in vivo; electrophysiological and immunohistological analysis ex vivo; and molecular cloning using affinity chromatography of high-performance affinity nanobeads; and protein processing measurement using bioluminescence resonance energy transfer (BRET) in vitro have generated new insights into pain transmission regulated by NST and N/OFQ. This review focuses on the molecular and cellular mechanisms of pain transmission regulated by NST.

Topics: Amino Acid Sequence; Animals; Humans; Molecular Sequence Data; Nociception; Opioid Peptides; Pain; Pain Measurement; Synapses; Time Factors

Nociceptin/orphanin FQ (N/OFQ) and nocistatin (NST) are neuropeptides produced from the same precursor protein. N/OFQ is involved in a broad range of central functions including pain, learning, memory, anxiety, and feeding. However, NST has opposite effects on various central functions evoked by N/OFQ. The regulation of their receptors may be important for these opposite functions of NST and N/OFQ. Although N/OFQ binds to a specific N/OFQ receptor, the target molecule of NST remains unclear. Some biological effects of NST are mediated by a G protein-coupled receptor. Furthermore, using high-performance affinity nanobeads, we recently identified a 4-nitrophenylphosphatase domain and nonneuronal SNAP25-like protein homolog 1 (NIPSNAP1) as a protein that interacts with NST in the mouse spinal cord. The inhibition of N/OFQ-evoked tactile pain allodynia by NST is mediated by NIPSNAP1. This review focuses on the molecular mechanisms of pain regulation by the target molecules of NST including a G protein-coupled receptor and NIPSNAP1.

Topics: Animals; Drugs, Investigational; GTP-Binding Protein alpha Subunits, Gq-G11; Humans; Intercellular Signaling Peptides and Proteins; Ligands; Narcotic Antagonists; Nerve Tissue Proteins; Neurons; Opioid Peptides; Pain; Proteins; Receptors, Opioid; Synaptic Transmission

Traditional concept holds that the pain unit consists of three neurons. The first of these, the primary nociceptive neuron, starts with the nociceptors and terminates in the dorsal spinal cord. The second one, called spinothalamic neuron, crosses over in front of the central canal and connects the dorsal horn with the thalamus. The third one, called thalamo-cortical neuron, terminates in the "pain centres" of the cerebral cortex. While this simplistic scheme is useful for didactic purposes, the actual situation is more complex. First, in the periphery it is only nociception that occurs, while pain is restricted to the levels of thalamus and the cortex. Second, pain results from interactions of excitation and inhibition, from divergence and convergence and from attention and distraction, in a diffuse and plastic system, characteristic for all levels of organization. This study describes the major cytochemical markers of primary nociceptive neurons followed by the presentation of recent data on the functional anatomy of nociception and pain, with special focus on the intrinsic antinociceptive system and the role of nitrogen oxide, opiate receptors, nociceptin and nocistatin. In addition to the classic intrinsic antinociceptive centres such as the periaqueductal gray matter and the raphe nuclei, roles of several recently discovered members of the antinociceptive system are discussed, such as the pretectal nucleus, the reticular formation, the nucleus accumbens, the nucleus tractus solitarii, the amygdala and the reticular thalamic nucleus, this latter being a coincidence detector and a centre for attention and distraction. The localisation of cortical centres involved in the generation of pain are presented based on the results of studies using imaging techniques, and the structural basis of corticospinal modulation is also outlined. Seven levels of nociception and pain are highlighted where pharmacological intervention may be successful, 1. the peripheral nociceptor, 2. the spinal ganglion, 3. the multisynaptic system of the dorsal horn, 4. the modulatory system of the brain stem, 5. the antinociceptive system, 6. the multisynaptic system of the thalamus, and 7. the cortical evaluating and localisation system that is also responsible for descending (inhibiting) control. The many levels of nociception and pain opens new ways both for pharmacological research and the general practitioner aiming to alleviate pain.

Topics: Analgesics; Brain Stem; Cerebral Cortex; Ganglia, Spinal; Humans; Neuronal Plasticity; Nitrogen Oxides; Nociceptin; Nociceptors; Opioid Peptides; Pain; Pain Measurement; Posterior Horn Cells; Receptors, Opioid; Spinothalamic Tracts; Thalamus

Hormonal imprinting develops at the first encounter between the target hormone and its developing receptor in the perinatal critical period. This determines the binding and response capacity of the receptor-signal transduction system and hormone production of cells for life. Molecules similar to the hormone and excess or absence of the target hormone cause faulty imprinting with lifelong consequences. Prenatal or neonatal imprinting with opiates, other drugs and prenatal stress have harmful consequences on the adult brain. Perinatal imprinting with endorphin or serotonin decreases the serotonin level of the brain while increasing sexual activity and (as in the case of endorphin) aggression. Endorphin or serotonin antagonist treatment at weaning (late imprinting) also significantly reduces the serotonin content of the brain. Backed by literary data, these observations are discussed, and the possible consequences of medical treatments are shown. The paper concludes that an excess of molecules produced by the brain itself can provoke perinatal imprinting, and it points to the possibility of late imprinting of the brain by receptor level acting agents, including a brain product (endorphin).

Topics: Analgesics, Opioid; Animals; Brain; Brain Chemistry; Endorphins; Hormones; Humans; Opioid Peptides; Pain; Serotonin; Signal Transduction

While acute pain has a fundamental role to operate a protective system, chronic pain associated with inflammation and nerve injury often outlasts its biological usefulness. Therefore, there has recently been great interest in the neurochemical mechanisms of hyperalgesia to noxious stimuli and tactile pain (allodynia) to innocuous stimuli with a hope to relieve persistent, intractable pain. Over several decades non-steroidal anti-inflammatory drugs and opioids have been employed for clinical management of pain. The introduction of molecular biology to pain research has enabled us to describe the mechanism of pain at the molecular level and to develop analgesics with selectivity for targets and with less adverse effects. This review focuses on current knowledge concerning mechanisms and pathways for pain induced by prostaglandins and their interactions with novel neuropeptides nociceptin/orphanin FQ and nocistatin derived from the same opioid precursor protein.

Topics: Analgesics; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acids; Brain; Cattle; Cyclooxygenase 1; Cyclooxygenase Inhibitors; Drug Synergism; Glutamic Acid; Humans; Hyperalgesia; Inflammation; Isoenzymes; Membrane Proteins; Mice; Mice, Knockout; Models, Animal; Models, Biological; Neuralgia; Neuronal Plasticity; Nitric Oxide; Nociceptin; Nociceptors; Opioid Peptides; Pain; Peripheral Nerves; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Protein Precursors; Rats; Spinal Cord; Thromboxane-A Synthase

Topics: Animals; Humans; Hyperalgesia; Mice; Mice, Knockout; Models, Neurological; Neuronal Plasticity; Neurons; Nociceptin; Opioid Peptides; Pain; Signal Transduction; Spinal Cord; Touch

Chronic pain associated with inflammation is an important clinical problem, and the underlying mechanisms remain poorly understood. 4-Nitrophenylphosphatase domain and nonneuronal SNAP25-like protein homolog (NIPSNAP) 1, an interacting protein with neuropeptide nocistatin, is implicated in the inhibition of tactile pain allodynia. Although nocistatin inhibits some inflammatory pain responses, whether NIPSNAP1 affects inflammatory pain appears to be unclear. Here, we examined the nociceptive behavioral response of NIPSNAP1-deficient mice and the expression of NIPSNAP1 following peripheral inflammation to determine the contribution of NIPSNAP1 to inflammatory pain.. Nociceptive behavioral response increased in phase II of the formalin test, particularly during the later stage (26-50 min) in NIPSNAP1-deficient mice, although the response during phase I (0-15 min) was not significantly different between the deficient and wild-type mice. Moreover, phosphorylation of extracellular signal-related kinase was enhanced in the spinal dorsal horn of the deficient mice. The prolonged inflammatory pain induced by carrageenan and complete Freund's adjuvant was exacerbated in NIPSNAP1-deficient mice. NIPSNAP1 mRNA was expressed in small- and medium-sized neurons of the dorsal root ganglion and motor neurons of the spinal cord. In the formalin test, NIPSNAP1 mRNA was slightly increased in dorsal root ganglion but not in the spinal cord. In contrast, NIPSNAP1 mRNA levels in dorsal root ganglion were significantly decreased during 24-48 h after carrageenan injection. Prostaglandin E2, a major mediator of inflammation, stimulated NIPSNAP1 mRNA expression via the cAMP-protein kinase A signaling pathway in isolated dorsal root ganglion cells.. These results suggest that changes in NIPSNAP1 expression may contribute to the pathogenesis of inflammatory pain.

Topics: Animals; Cyclooxygenase Inhibitors; Dinoprostone; Formaldehyde; Ganglia, Spinal; Inflammation; Intercellular Signaling Peptides and Proteins; Membrane Proteins; Mice; Neuropeptides; Opioid Peptides; Pain; Proteins; RNA, Messenger

4-Nitrophenylphosphatase domain and non-neuronal SNAP25-like protein homolog 1 (NIPSNAP1) is a molecule of physiologically unknown function, although it is predominantly expressed in the brain, spinal cord, liver, and kidney. We identified NIPSNAP1 as a protein that interacts with the neuropeptide nocistatin (NST) from synaptosomal membranes of mouse spinal cord using high-performance affinity latex beads. NST, which is produced from the same precursor protein as an opioid-like neuropeptide nociceptin/orphanin FQ (N/OFQ), has opposite effects on pain transmission evoked by N/OFQ. The calculated full-length pre-protein of NIPSNAP1 was 33 kDa, whereas the N-terminal truncated form of NIPSNAP1 (29 kDa) was ubiquitously expressed in the neuronal tissues, especially in synaptic membrane and mitochondria of brain. The 29-kDa NIPSNAP1 was distributed on the cell surface, and NST interacted with the 29-kDa but not the 33-kDa NIPSNAP1. Although intrathecal injection of N/OFQ induced tactile allodynia in both wild-type and NIPSNAP1-deficient mice, the inhibition of N/OFQ-evoked tactile allodynia by NST seen in wild-type mice was completely lacking in the deficient mice. These results suggest that NIPSNAP1 is an interacting molecule of NST and plays a crucial role in pain transmission.

Topics: Analgesics, Opioid; Animals; Brain; Chlorocebus aethiops; COS Cells; Humans; Hyperalgesia; Intercellular Signaling Peptides and Proteins; Membrane Proteins; Mice; Mitochondria; Nerve Tissue Proteins; Opioid Peptides; Pain; Proteins; Spinal Cord; Synaptic Membranes; Synaptic Transmission

Central amygdala nucleus (CeA)-periaqueductal gray (PAG) pathway is the component of descending antinociceptive circuitry. Nociceptin/orphanin FQ (N/OFQ) and nocistatin (NST) produce supraspinal pronociceptive and antinociceptive effects, respectively. We hypothesized that opposite effects of N/OFQ and NST on supraspinal pain modulation result from their opposing effects on the excitability of CeA-PAG projection neurons. This hypothesis was tested by investigating electrophysiological effects of N/OFQ and NST on medial CeA neurons that project to PAG (CeA(M)-PAG). N/OFQ hyperpolarized CeA(M)-PAG projection neurons by enhancing inwardly rectifying potassium conductance. In contrast, NST depolarized CeA(M)-PAG neurons by causing the opening of TRPC cation channels via G(alphaq/11)-PLC-PKC pathway. CeA(M)-PAG neurons hyperpolarized by N/OFQ express CRF or neurotensin mRNA. NST-responsive CeA(M)-PAG neurons contain CRF or substance P mRNA. Our study provides the evidence that the molecular and cellular basis for opposite effects of N/OFQ and NST on supraspinal pain regulation is their opposing effects on the excitability of peptidergic CeA(M)-PAG neurons.

Topics: Amygdala; Animals; Efferent Pathways; Membrane Potentials; Neurons; Nociceptin; Opioid Peptides; Pain; Patch-Clamp Techniques; Periaqueductal Gray; Potassium Channels, Inwardly Rectifying; Rats; Rats, Sprague-Dawley

Neuropeptides nociceptin/orphanin FQ (N/OFQ) and nocistatin (NST) are related to pain modulation. The amounts of these peptides and their precursor protein, prepronociceptin (ppN/OFQ) in the brain, spinal cord and serum samples of rats with partial sciatic nerve ligation (PSNL) were compared with those in naïve rats using radioimmunoassay (RIA). There was a significant rise in the levels of ppN/OFQ, N/OFQ and NST in the brains of PSNL rats. Their spinal cords showed significantly increased ppN/OFQ and NST levels but no change in N/OFQ levels. The PSNL rats also had increased serum NST (statistically significant) and N/OFQ (statistically insignificant) with decreased ppN/OFQ suggesting important roles of these peptides in neuropathic pain mechanism.

Topics: Animals; Antibodies; Brain; Hyperalgesia; Male; Models, Animal; Nociceptin; Opioid Peptides; Pain; Pain Measurement; Protein Precursors; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Receptors, Opioid; Sciatic Nerve; Spinal Cord

Nocistatin (NST) and nociceptin/orphanin FQ (NCP) are two important bio-peptides derived from the precursor protein prepronociceptin (ppNCP), involved in several central nervous system (CNS) functions including pain transmission. Since the actual form of human NST in CNS is not fully characterized, we studied the structure of NST from human brain tissue and cerebrospinal fluid (CSF) samples. NST and NCP were isolated from human brain and CSF samples by affinity chromatography combined with HPLC. Mass spectrometry was used for the identification and characterization of the peptides. The total NST immunoreactivity was detected as 11.5+/-2.3 pmol/g tissue for the brain and 0.44 pmol/ml for the pooled CSF sample after the HPLC purification by radioimmunoassay. The presence of two different forms of mature nocistatin (NST-17 and NST-30) and a possible N-terminal methionine cleaved NST-29 were confirmed by both radioimmunoassay and mass spectrometry. Affinity chromatography, HPLC and mass spectrometry methods used in this study were highly sensitive and suitable for identification of actual chemical structures and quantification of very small amounts of peptides in biological samples. The present findings may help further for search for new treatment of neuropathic pain, which is often poorly managed by current therapies.

Topics: Amino Acid Sequence; Animals; Brain Chemistry; Chromatography, Affinity; Chromatography, High Pressure Liquid; Humans; Methionine; Molecular Sequence Data; Neuropeptides; Nociceptin; Opioid Peptides; Pain; Protein Isoforms; Protein Precursors; Radioimmunoassay; Receptors, Opioid; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Nocistatin and Nociceptin/Orphanin FQ are two neuropeptides derived from the same precursor protein, pre-pro-Nociceptin. Nocistatin does not bind to Nociceptin/Orphanin FQ peptide (NOP) receptor but it antagonizes the allodynic and hyperalgesic effect of intrathecal (i.t.) Nociceptin. In this study, we examined the effect of Nocistatin on nociception and opioid analgesia by itself and the nociceptive effect of Nociceptin and antagonistic effect of nociceptin on opioid receptors in tail flick test when given the i.c.v. route. More precisely, supraspinal Nocistatin by itself had no significative effect on nociception and opioid analgesia in the tail flick test but, at the dose of 0.5ng/rat, it reversed the nociceptive effect of Nociceptin and also the antagonistic effect of Nociceptin against analgesia caused by the selective opioid agonists: DAMGO, DPDPE, Deltorphin II and U50 488H. These data suggest that Nocistatin antagonizes the effect of Nociceptin on opioid analgesia and could play an important role in the regulation of nociceptive transmission.

Topics: Analgesics, Opioid; Animals; Brain; Dose-Response Relationship, Drug; Drug Interactions; Injections, Intraventricular; Male; Nociceptin; Opioid Peptides; Pain; Pain Measurement; Rats; Rats, Sprague-Dawley; Treatment Outcome

The neuropeptide nocistatin (NST) has been implicated in the modulation of nociceptive responses in the spinal cord. Depending on the dose, both pronociceptive and antinociceptive effects have repeatedly been reported. The pronociceptive effect is most likely attributable to inhibition of synaptic glycine and gamma-aminobutyric acid release and a subsequent reduction in the activation of inhibitory glycine and gamma-aminobutyric acid receptors, but the mechanisms of its antinociceptive action have hitherto remained elusive. It has recently been demonstrated that synaptically released glycine contributes to N-methyl-D-aspartate receptor activation. The authors therefore investigated whether a reduction in glycine release might also account for the antinociceptive action of NST in neuropathic rats.. The authors analyzed the effects of spinally applied NST in the chronic constriction injury model of neuropathic pain. NST was injected intrathecally from nanomolar to picomolar doses and its effects on thermal paw withdrawal latencies were monitored. Furthermore, we tested whether D-serine (100 microg per rat), a full agonist at the glycine binding site of the N-methyl-D-aspartate receptor, would interfere with the effects of NST.. At high doses (10 nmol/rat), intrathecally injected NST was pronociceptive, whereas lower doses (1 pmol/rat) elicited antinociception. The antinociceptive, but not the pronociceptive, action was occluded by intrathecal pretreatment with D-serine. L-serine, which does not bind to N-methyl-D-aspartate receptors, affected neither the pronociceptive nor the antinociceptive effect.. These results demonstrate that NST produces a biphasic dose-dependent effect on neuropathic pain. The spinal antinociception by NST is most likely attributable to inhibition of glycine-dependent N-methyl-D-aspartate receptor activation.

Topics: Analgesics, Opioid; Anesthesia, Spinal; Animals; Dose-Response Relationship, Drug; Glycine; Hyperalgesia; Injections, Spinal; Ligation; Opioid Peptides; Pain; Rats; Rats, Wistar; Receptors, N-Methyl-D-Aspartate; Sciatic Neuropathy; Serine; Stereoisomerism

Nociceptin/orphanin FQ (N/OFQ), nocistatin, and prepro-N/OFQ 160-187 (C-peptide) are all derived from the same precursor protein. We examine the pharmacological mechanisms of nocistatin- and C-peptide-induced pronociceptive responses in a novel algogenic-induced nociceptive flexion test in mice. The intraplantar (i.pl.) injection of nocistatin- and C-peptide induced pronociceptive responses in a range of 0.01 to 10 or 1 pmol, respectively, which showed 100- to 1000-fold less potent effects than the N/OFQ. The nociceptive effects of both peptides were not affected by 1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl-1,3-dihydro-2H-benzimidazole-2-one (J-113397) (i.pl.), an N/OFQ receptor antagonist, indicating that they are mediated by a novel mechanism independent of activation of N/OFQ receptor. Like N/OFQ, nocistatin-induced nociception was abolished by i.pl. injection of pertussis toxin, phospholipase C inhibitor, or CP-99994, a neurokinin 1 receptor antagonist, indicating that nocistatin may elicit nociception through a substance P release from nociceptor endings via activation of Gi/o and phospholipase C. The nociception was abolished by neonatal pretreatment (s.c.) with capsaicin or by i.t. pretreatment with CP-99994, but not MK-801 (i.t.), an N-methyl-d-aspartate receptor antagonist. In contrast, C-peptide-induced nociception was attenuated by the pretreatment with antisense oligodeoxynucleotide for Galphas (i.t.) and with KT-5720 (i.pl.), a cyclic AMP-dependent protein kinase inhibitor, but not with pertussis toxin. The nociception was neither attenuated by neonatal capsaicin nor by i.t. injection with CP-99994, but it was attenuated by i.t. injection with MK-801. These results suggest that nocistatin and C-peptide derived from prepro-N/OFQ stimulate distinct nociceptive fibers through different in vivo signaling mechanisms.

Topics: Analgesics, Opioid; Animals; C-Peptide; Capsaicin; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gs; Male; Mice; Nociceptin; Nociceptors; Opioid Peptides; Pain; Pain Measurement; Peptide Fragments; Signal Transduction; Vasodilator Agents

Nocistatin and nociceptin/orphanin FQ (N/OFQ) are two neuropeptides derived from the same precursor protein, prepronociceptin (ppOFQ), and exhibit different effects on spinal neurotransmission. Nocistatin does not bind to nociceptin/orphanin FQ peptide receptor (NOP), but intrathecal (i.t.) nocistatin has been reported to block the analgesic effect of i.t. N/OFQ. In this study, we investigated the effect of i.t. nocistatin on N/OFQ analgesia to radiant thermal stimuli in chronic constriction injury (CCI) rat. Firstly, to investigate the analgesic effect of N/OFQ, different doses of N/OFQ (3, 10, 30 microg) were intrathecally injected and foot withdrawal latency (FWL) to radiant heat was recorded. It is observed that 3 microg N/OFQ had no effect on FWL, 10 and 30 microg N/OFQ significantly increased FWL of CCI rat. Then, 10 microg N/OFQ, 10 microg nocistatin and a drug cocktail including 10 microg N/OFQ and 10 microg nocistatin were intrathecally injected. The results showed that FWL significantly decreased after using N/OFQ and nocistatin compared with using only N/OFQ, and 10 microg nocistatin had no effect on FWL versus control, suggesting that this dose of nocistatin per se had no effect on the pain threshold of CCI rat, but could block the analgesic effect of N/OFQ. These results indicated that i.t. N/OFQ dose-relatedly depressed thermal hyperalgesia produced by CCI and nocistatin could block N/OFQ analgesia at spinal level in CCI rat.

Topics: Analgesics, Opioid; Animals; Constriction, Pathologic; Dose-Response Relationship, Drug; Hot Temperature; Injections, Spinal; Male; Nociceptin; Opioid Peptides; Pain; Rats; Rats, Sprague-Dawley; Receptors, Opioid; Sciatic Nerve; Time Factors

The actions of the endogenous ORL1 receptor (opioid receptor-like1) ligand nociceptin on the membrane properties of rat trigeminal nucleus caudalis neurons were examined by use of whole cell and perforated patch clamp recording in brain slices. Nociceptin produced an outward current in all neurons tested (EC50 112 nM). The outward current produced by nociceptin was completely reversed with the addition of the non-peptide ORL1 antagonist J-113397. Outward currents reversed polarity at -99+/-2 mV, close to the potential for K+ of -102 mV, suggesting that they were mediated by an increased K+ conductance. These results suggest that the analgesic action of nociceptin might be mediated by direct postsynaptic inhibition within the dorsal horn.

Topics: Analgesics, Opioid; Animals; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Excitatory Postsynaptic Potentials; Nociceptin; Nociceptin Receptor; Opioid Peptides; Pain; Patch-Clamp Techniques; Posterior Horn Cells; Potassium; Rats; Rats, Sprague-Dawley; Receptors, Opioid; Substantia Gelatinosa; Trigeminal Caudal Nucleus; Vasodilator Agents

Nocistatin is a 17 amino acid peptide and is processed from prepronociceptin. Nocistatin does not bind to the nociceptin receptor, but nocistatin blocks allodynia induced by nociceptin/orphanin FQ. In this study, we examined the effect of intrathecal nocistatin and its interaction with nociceptin/orphanin FQ in the rat formalin test and the hot plate test. Intrathecal nocistatin attenuated the formalin induced phase 1, but not phase 2, flinching behavior. Coadministration of nocistatin with nociceptin/orphanin FQ did not block the analgesic effect of nociceptin/orphanin FQ. Nocistatin had no effect on the hot plate test. These data suggest that nocistatin produces analgesic effect in the formalin test, but not in the hot plate test, and that the mechanisms underlying the analgesic effect of nocistatin is complex.

Topics: Analysis of Variance; Animals; Dose-Response Relationship, Drug; Formaldehyde; Hot Temperature; Injections, Spinal; Male; Nociceptin; Opioid Peptides; Pain; Rats; Rats, Sprague-Dawley; Receptors, Opioid; Spinal Cord

Prolonged tissue damage or injury often leads to chronic pain states such that noxious stimuli evoke hyperalgesia and innocuous tactile stimuli evoke pain (allodynia). The neuropeptide nociceptin, also known as orphanin FQ, is an endogenous ligand for the orphan opioid-like receptor which induces both hyperalgesia and allodynia when administered by injection through the theca of the spinal cord into the subarachnoid space (that is, intrathecally). Here we show that the nociceptin precursor contains another biologically active peptide which we call nocistatin. Nocistatin blocks nociceptin-induced allodynia and hyperalgesia, and attenuates pain evoked by prostaglandin E2. It is the carboxy-terminal hexapeptide of nocistatin (Glu-Gln-Lys-Gln-Leu-Gln), which is conserved in bovine, human and murine species, that possesses allodynia-blocking activity. We have also isolated endogenous nocistatin from bovine brain. Furthermore, intrathecal pretreatment with anti-nocistatin antibody decreases the threshold for nociceptin-induced allodynia. Although nocistatin does not bind to the nociceptin receptor, it binds to the membrane of mouse brain and of spinal cord with high affinity. Our results show that nocistatin is a new biologically active peptide produced from the same precursor as nociceptin and indicate that these two peptides may play opposite roles in pain transmission.

Topics: Amino Acid Sequence; Animals; Antibodies; Brain Chemistry; Cattle; Cloning, Molecular; Cricetinae; Cricetulus; Dinoprostone; Humans; Hyperalgesia; Male; Mice; Molecular Sequence Data; Nociceptin; Nociceptin Receptor; Opioid Peptides; Pain; Protein Precursors; Protein Processing, Post-Translational; Rats; Receptors, Opioid; Sequence Homology, Amino Acid; Spinal Cord

Topics: Animals; Cattle; Hyperalgesia; Injections, Spinal; Mice; Opioid Peptides; Pain