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Tyagi A, Daliri EBM, Kwami Ofosu F, Yeon SJ, Oh DH. Food-Derived Opioid Peptides in Human Health: A Review. Int J Mol Sci 2020; 21:E8825. [PMID: 33233481 PMCID: PMC7700510 DOI: 10.3390/ijms21228825] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/19/2020] [Accepted: 11/19/2020] [Indexed: 12/12/2022] Open
Abstract
World Health Organization data suggest that stress, depression, and anxiety have a noticeable prevalence and are becoming some of the most common causes of disability in the Western world. Stress-related disorders are considered to be a challenge for the healthcare system with their great economic and social impact. The knowledge on these conditions is not very clear among many people, as a high proportion of patients do not respond to the currently available medications for targeting the monoaminergic system. In addition, the use of clinical drugs is also associated with various side effects such as vomiting, dizziness, sedation, nausea, constipation, and many more, which prevents their effective use. Therefore, opioid peptides derived from food sources are becoming one of the safe and natural alternatives because of their production from natural sources such as animals and plant proteins. The requirement for screening and considering dietary proteins as a source of bioactive peptides is highlighted to understand their potential roles in stress-related disorders as a part of a diet or as a drug complementing therapeutic prescription. In this review, we discussed current knowledge on opioid endogenous and exogenous peptides concentrating on their production, purification, and related studies. To fully understand their potential in stress-related conditions, either as a drug or as a therapeutic part of a diet prescription, the need to screen more dietary proteins as a source of novel opioid peptides is emphasized.
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Affiliation(s)
| | | | | | | | - Deog-Hwan Oh
- Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Korea; (A.T.); (E.B.-M.D.); (F.K.O.); (S.-J.Y.)
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Lénárd L, László K, Kertes E, Ollmann T, Péczely L, Kovács A, Kállai V, Zagorácz O, Gálosi R, Karádi Z. Substance P and neurotensin in the limbic system: Their roles in reinforcement and memory consolidation. Neurosci Biobehav Rev 2018; 85:1-20. [DOI: 10.1016/j.neubiorev.2017.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/24/2017] [Accepted: 09/02/2017] [Indexed: 12/18/2022]
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3
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Campolongo P, Ratano P, Ciotti MT, Florenzano F, Nori SL, Marolda R, Palmery M, Rinaldi AM, Zona C, Possenti R, Calissano P, Severini C. Systemic administration of substance P recovers beta amyloid-induced cognitive deficits in rat: involvement of Kv potassium channels. PLoS One 2013; 8:e78036. [PMID: 24265678 PMCID: PMC3827079 DOI: 10.1371/journal.pone.0078036] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/16/2013] [Indexed: 11/18/2022] Open
Abstract
Reduced levels of Substance P (SP), an endogenous neuropeptide endowed with neuroprotective and anti-apoptotic properties, have been found in brain and spinal fluid of Alzheimer's disease (AD) patients. Potassium (K(+)) channel dysfunction is implicated in AD development and the amyloid-β (Aβ)-induced up-regulation of voltage-gated potassium channel subunits could be considered a significant step in Aβ brain toxicity. The aim of this study was to evaluate whether SP could reduce, in vivo, Aβ-induced overexpression of Kv subunits. Rats were intracerebroventricularly infused with amyloid-β 25-35 (Aβ25-35, 20 µg) peptide. SP (50 µg/Kg, i.p.) was daily administered, for 7 days starting from the day of the surgery. Here we demonstrate that the Aβ infused rats showed impairment in cognitive performances in the Morris water maze task 4 weeks after Aβ25-35 infusion and that this impairing effect was prevented by SP administration. Kv1.4, Kv2.1 and Kv4.2 subunit levels were quantified in hippocampus and in cerebral cortex by Western blot analysis and immunofluorescence. Interestingly, SP reduced Kv1.4 levels overexpressed by Aβ, both in hippocampus and cerebral cortex. Our findings provide in vivo evidence for a neuroprotective activity of systemic administration of SP in a rat model of AD and suggest a possible mechanism underlying this effect.
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Affiliation(s)
- Patrizia Campolongo
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Patrizia Ratano
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | | | - Fulvio Florenzano
- Institute of Cell Biology and Neurobiology, CNR, Rome, Italy
- European Brain Research Institute, Rome, Italy
| | - Stefania Lucia Nori
- Department of Medicine and Surgery, University of Salerno Medicine Campus, Baronissi (SA), Italy
| | - Roberta Marolda
- Institute of Cell Biology and Neurobiology, CNR, Rome, Italy
| | - Maura Palmery
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Anna Maria Rinaldi
- Department of Neuroscience, University of Rome “Tor Vergata”, Rome, Italy
| | - Cristina Zona
- Department of Neuroscience, University of Rome “Tor Vergata”, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Roberta Possenti
- Department of Neuroscience, University of Rome “Tor Vergata”, Rome, Italy
| | | | - Cinzia Severini
- Institute of Cell Biology and Neurobiology, CNR, Rome, Italy
- * E-mail:
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4
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McLay RN, Pan W, Kastin AJ. Effects of peptides on animal and human behavior: a review of studies published in the first twenty years of the journal Peptides. Peptides 2001; 22:2181-255. [PMID: 11786208 DOI: 10.1016/s0196-9781(01)00550-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This review catalogs effects of peptides on various aspects of animal and human behavior as published in the journal Peptides in its first twenty years. Topics covered include: activity levels, addiction behavior, ingestive behaviors, learning and memory-based behaviors, nociceptive behaviors, social and sexual behavior, and stereotyped and other behaviors. There are separate tables for these behaviors and a short introduction for each section.
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Affiliation(s)
- R N McLay
- Naval Medical Center San Diego, Department of Psychiatry, San Diego, CA, USA
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D'Hooge R, De Deyn PP. Applications of the Morris water maze in the study of learning and memory. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2001; 36:60-90. [PMID: 11516773 DOI: 10.1016/s0165-0173(01)00067-4] [Citation(s) in RCA: 1394] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Morris water maze (MWM) was described 20 years ago as a device to investigate spatial learning and memory in laboratory rats. In the meanwhile, it has become one of the most frequently used laboratory tools in behavioral neuroscience. Many methodological variations of the MWM task have been and are being used by research groups in many different applications. However, researchers have become increasingly aware that MWM performance is influenced by factors such as apparatus or training procedure as well as by the characteristics of the experimental animals (sex, species/strain, age, nutritional state, exposure to stress or infection). Lesions in distinct brain regions like hippocampus, striatum, basal forebrain, cerebellum and cerebral cortex were shown to impair MWM performance, but disconnecting rather than destroying brain regions relevant for spatial learning may impair MWM performance as well. Spatial learning in general and MWM performance in particular appear to depend upon the coordinated action of different brain regions and neurotransmitter systems constituting a functionally integrated neural network. Finally, the MWM task has often been used in the validation of rodent models for neurocognitive disorders and the evaluation of possible neurocognitive treatments. Through its many applications, MWM testing gained a position at the very core of contemporary neuroscience research.
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Affiliation(s)
- R D'Hooge
- Laboratory of Neurochemistry and Behavior, Born-Bunge Foundation, and Department of Neurology/Memory Clinic, Middelheim Hospital, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.
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De Souza Silva MA, Hasenöhrl RU, Tomaz C, Schwarting RK, Huston JP. Differential modulation of frontal cortex acetylcholine by injection of substance P into the nucleus basalis magnocellularis region in the freely-moving vs. the anesthetized preparation. Synapse 2000; 38:243-53. [PMID: 11020227 DOI: 10.1002/1098-2396(20001201)38:3<243::aid-syn3>3.0.co;2-g] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In vivo microdialysis was used to assess the effects of unilateral substance P (SP) injection into the nucleus basalis magnocellularis on extracellular levels of acetylcholine (ACh) in the frontal cortex, either in freely moving or urethane-anesthetized rats. The results show that the neurochemical effects of SP are critically dependent on the choice of the experimental preparation: In the freely-moving rat, the injection procedure led to behavioral and concurrent bilateral cholinergic activation in the frontal cortex. This cholinergic activation was ipsilaterally reduced by intrabasalis injection of SP (1 ng), indicating that the peptide exerted an inhibitory influence on the neurochemical effect exerted by handling, intracranial needle insertion, and vehicle injection. In the anesthetized preparation, SP had a biphasic dose-dependent action on cortical ACh: a short-lasting ipsilateral increase immediately after injection (especially with 1 ng), and a delayed bilateral increase after more than 2 h (10, 100 ng). The procedure of inserting the injection needle moderately increased cortical ACh levels. Methodologically, these data are discussed with respect to the importance of using anesthetized vs. freely moving rats and the effects of intraparenchymal injections.
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Affiliation(s)
- M A De Souza Silva
- Institute of Physiological Psychology I, University of Düsseldorf, Düsseldorf, Germany
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7
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Kouznetsova M, Nistri A. Facilitation of cholinergic transmission by substance P methyl ester in the mouse hippocampal slice preparation. Eur J Neurosci 2000; 12:585-94. [PMID: 10712638 DOI: 10.1046/j.1460-9568.2000.00942.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Using sharp microelectrode recording from CA1 pyramidal neurons of the adult mouse hippocampal slice preparation, we studied the modulatory action of the selective neurokinin 1 (NK1) receptor agonist substance P methyl ester (SPME), a peptidase-resistant analogue of the peptide substance P (SP), on cholinergic responses. While SPME (0.1-1 microM) had only slight effects on membrane potential and input resistance of CA1 neurons, it largely and reversibly enhanced the membrane depolarization and oscillatory activity induced by the cholinergic agonist carbachol (CCh; 0.1-100 microM). This effect of SPME was prevented by the selective NK1 receptor antagonist SR 140333 (4 microM). In about half of the tested neurons the action of SPME was preserved in tetrodotoxin (TTX) solution, suggesting that it partly occurred at the level of pyramidal cells. Cholinergic slow excitatory postsynaptic potentials (sEPSPs) were reversibly enhanced by SPME which increased their amplitude and prolonged any associated bursting activity. This action was also blocked by SR 140333. The present results suggest that SPME largely enhances cholinergic activity in the mouse hippocampus, an effect which can help to explain, in this brain area, the recently reported facilitation of seizures by SP.
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Affiliation(s)
- M Kouznetsova
- Biophysics Sector and INFM Unit, International School for Advanced Studies (SISSA), 34014 Trieste, Italy
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Bracci-Laudiero L, Aloe L, Lundeberg T, Theodorsson E, Stenfors C. Altered levels of neuropeptides characterize the brain of lupus prone mice. Neurosci Lett 1999; 275:57-60. [PMID: 10554984 DOI: 10.1016/s0304-3940(99)00737-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
It has been reported that more than 50% of lupus patients show various forms of neurological deficits including impaired cognitive functions and psychiatric disorders. Using an animal model of lupus we investigated the production of neuropeptides in the brain of NZB/W F1 female hybrid mice and its parental strain NZB and NZW. Our results indicate that the alteration in learning and memory described in lupus mice are paralleled by a decrease in calcitonin gene-related peptide, substance P and neuropeptide Y (NPY) levels in the hippocampus and a significant decrease of NPY in the cortex. These findings are interesting in the light of previously reported results suggesting that these neuropeptides can play an important role in cognitive functions. We also observed a decrease of NPY and vasoactive intestinal polypeptide levels in the hypothalamus of lupus prone mice and these changes may be related to the disregulation of the hypothalamus-pituitary-adrenal axis observed in lupus prone mice.
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Affiliation(s)
- L Bracci-Laudiero
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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9
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Pan W, Kastin AJ, Banks WA, Zadina JE. Effects of peptides: a cross-listing of peptides and their central actions published in the journal Peptides from 1994 through 1998. Peptides 1999; 20:1127-38. [PMID: 10499432 DOI: 10.1016/s0196-9781(99)00109-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Effects of peptides on the central nervous system are presented in two ways so as to provide a cross-listing. In the first table, the peptides are listed alphabetically. In the second table, the central nervous system effects are arranged alphabetically. No longer can there be any doubt that peptides affect the central nervous system, sometimes in several ways.
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Affiliation(s)
- W Pan
- VA Medical Center and Tulane University School of Medicine, Neuroscience Training Program and Department of Medicine, New Orleans, LA 70112-1262, USA.
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Tzschentke TM. Measuring reward with the conditioned place preference paradigm: a comprehensive review of drug effects, recent progress and new issues. Prog Neurobiol 1998; 56:613-72. [PMID: 9871940 DOI: 10.1016/s0301-0082(98)00060-4] [Citation(s) in RCA: 917] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review gives an overview of recent findings and developments in research on brain mechanisms of reward and reinforcement from studies using the place preference conditioning paradigm, with emphasis on those studies that have been published within the last decade. Methodological issues of the paradigm (such as design of the conditioning apparatus, biased vs unbiased conditioning, state dependency effects) are discussed. Results from studies using systemic and local (intracranial) drug administration, natural reinforcers, and non-drug treatments and from studies examining the effects of lesions are presented. Papers reporting on conditioned place aversion (CPA) experiments are also included. A special emphasis is put on the issue of tolerance and sensitization to the rewarding properties of drugs. Transmitter systems that have been investigated with respect to their involvement in brain reward mechanisms include dopamine, opioids, acetylcholine, GABA, serotonin, glutamate, substance P, and cholecystokinin, the motivational significance of which has been examined either directly, by using respective agonist or antagonist drugs, or indirectly, by studying the effects of these drugs on the reward induced by other drugs. For a number of these transmitters, detailed studies have been conducted to delineate the receptor subtype(s) responsible for the mediation of the observed drug effects, particularly in the case of dopamine, the opioids, serotonin and glutamate. Brain sites that have been implicated in the mediation of drug-induced place conditioning include the 'traditional' brain reward sites, ventral tegmental area and nucleus accumbens, but the medial prefrontal cortex, ventral pallidum, amygdala and the pedunculopontine tegmental nucleus have also been shown to play important roles in the mediation of place conditioning induced by drugs or natural reinforcers. Thus, although the paradigm has also been criticized because of some inherent methodological problems, it is clear that during the past decade place preference conditioning has become a valuable and firmly established and very widely used tool in behavioural pharmacology and addiction research.
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Affiliation(s)
- T M Tzschentke
- Department of Neuropharmacology, University of Tübingen, Germany.
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11
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Kouznetsova M, Nistri A. Modulation by substance P of synaptic transmission in the mouse hippocampal slice. Eur J Neurosci 1998; 10:3076-84. [PMID: 9786202 DOI: 10.1046/j.1460-9568.1998.00318.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The modulatory action of substance P on synaptic transmission of CA1 neurons was studied using intra- or extracellular recording from the mouse hippocampal slice preparation. Bath-applied substance P (2-4 microM) or the selective NK1 receptor agonist substance P methylester (SPME, 10 nM-5 microM) depressed field potentials (recorded from stratum pyramidale) evoked by focal stimulation of Schaffer collaterals. This effect was apparently mediated via NK1 receptors since it was completely blocked by the selective NK1 antagonist SR 140333. The field potential depression by SPME was significantly reduced in the presence of bicuculline. Intracellular recording from CA1 pyramidal neurons showed that evoked excitatory postsynaptic potentials (EPSPs) and evoked inhibitory postsynaptic potentials (IPSPs) were similarly depressed by SPME, which at the same time increased the frequency of spontaneous GABAergic events and reduced that of spontaneous glutamatergic events. The effects of SPME on spontaneous and evoked IPSPs were prevented by the ionotropic glutamate receptor blocker kynurenic acid. In tetrodotoxin (TTX) solution, no change in either the frequency of spontaneous GABAergic and glutamatergic events or in the amplitude of responses of pyramidal neurons to 4 microM alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) or 10 microM N-methyl-D-aspartate (NMDA) was observed. On the same cells, SPME produced minimal changes in passive membrane properties unable to account for the main effects on synaptic transmission. The present data indicate that SPME exerted its action on CA1 pyramidal neurons via a complex network mechanism, which is hypothesized to involve facilitation of a subset of GABAergic neurons with widely distributed connections to excitatory and inhibitory cells in the CA1 area.
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Affiliation(s)
- M Kouznetsova
- Biophysics Sector and INFM Unit, International School for Advanced Studies (SISSA), Trieste, Italy
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12
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Schechter MD, Calcagnetti DJ. Continued trends in the conditioned place preference literature from 1992 to 1996, inclusive, with a cross-indexed bibliography. Neurosci Biobehav Rev 1998; 22:827-46. [PMID: 9809314 DOI: 10.1016/s0149-7634(98)00012-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In light of the overwhelming response to the previous publication in Neuroscience and Biobehavioral Reviews (1993, 17, 21-41) regarding trends in place conditioning (either preference or aversion), the present work constitutes a five-year follow-up to review the empirical research in this behavioral paradigm from 1992 to 1996, inclusively. The behavioral technique has grown as indicated by the number of publications over the last five years which equals those authored over the 35 years covered by our last survey. The previous work used descriptive statistics to explore topical issues, whereas the present work discusses trends since that time and hopes to provide an exhaustive bibliography of the CPP literature, including articles, published abstracts, book chapters and reviews, as well as providing a cross-index of identified key words/drugs tested.
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Affiliation(s)
- M D Schechter
- Department of Pharmacology, Northeastern Ohio University College of Medicine, Rootstown 44272-0095, USA.
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Hasenöhrl RU, Jentjens O, De Souza Silva MA, Tomaz C, Huston JP. Anxiolytic-like action of neurokinin substance P administered systemically or into the nucleus basalis magnocellularis region. Eur J Pharmacol 1998; 354:123-33. [PMID: 9754912 DOI: 10.1016/s0014-2999(98)00441-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
There is evidence that the neurokinin substance P plays a role in neural mechanisms governing learning and reinforcement. Reinforcing and memory-promoting effects of substance P were found after it was injected into several parts of the brain and intraperitoneally. With regard to the close link between anxiety and memory processes for negative reinforcement learning, the aim of the present study was to gauge the effect of substance P on anxiety-related behaviors in the rat elevated plus-maze and social interaction test. Substance P was tested at injection sites where the neurokinin has been shown to promote learning and to serve as a reinforcer, namely in the periphery (after i.p. administration) and after injection into the nucleus basalis magnocellularis region. When administered i.p., substance P had a biphasic dose-response effect on behavior in the plus-maze with an anxiolytic-like action at 50 microg/kg and an anxiogenic-like one at 500 microg/kg. After unilateral microinjection into the nucleus basalis magnocellularis region, substance P (1 ng) was found to exert anxiolytic-like effects, because substance P-treated rats spent more time on the open arms of the plus-maze and showed an increase in time spent in social interaction. Furthermore, the anxiolytic effects of intrabasalis substance P were sequence-specific since injection of a compound with the inverse amino acid sequence of substance P (0.1 to 100 ng) did not influence anxiety parameters. These results show that substance P has anxiolytic-like properties in addition to its known promnestic and reinforcing effects, supporting the hypothesis of a close relationship between anxiety, memory and reinforcement processes.
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Affiliation(s)
- R U Hasenöhrl
- Institute of Physiological Psychology and Center for Biological and Medical Research, University of Düsseldorf, Germany.
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Nikolaus S, Huston JP, Körber B, Thiel C, Schwarting RK. Pretreatment with neurokinin substance P but not with cholecystokinin-8S can alleviate functional deficits of partial nigrostriatal 6-hydroxydopamine lesion. Peptides 1997; 18:1161-8. [PMID: 9396056 DOI: 10.1016/s0196-9781(97)00181-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The neuropeptide substance P (SP) has been implicated in the control of various neuro-behavioral functions including reinforcement and learning processes. It also exerts neurotrophic and regenerating effects in vitro and in vivo. A previous study indicated a potential therapeutic effect of SP in rats with partial 6-hydroxydopamine lesions of the nigrostriatal dopamine system when SP was administered after the lesion. The purpose of the present study was to determine whether prelesion treatment with SP would also interact with the effects of unilateral 6-hydroxydopamine lesion of the substantia nigra. Thus, SP (50 micrograms/kg) was administered i.p. on 8 consecutive days prior to unilateral lesion of the substantia nigra. Furthermore, we investigated the effects of prelesion treatment with cholecystokinin-8S (CCK; 1 microgram/kg), another neuropeptide, which is closely related to dopaminergic neurons, and which also can have neurotrophic and neuroprotective functions. Our results show that animals with partial neostriatal dopamine depletions (residual dopamine levels of more than 10%) did not show turning asymmetries when pretreated with SP, whereas animals pretreated with vehicle exhibited an initial ipsiversive asymmetry from which they recovered. In contrast, behavioral asymmetries were most pronounced in animals which had been pretreated with CCK. These peptide treatments did not affect the degree of neostriatal dopamine depletion; however, dihydroxyphenylacetic acid/dopamine ratios were enhanced in the neurostriatum of animals with partial dopamine damage after SP- and CCK-pretreatment, and in the ventral striatum of SP-pretreated animals. These data provide evidence that prelesion treatment with SP, but not with CCK, can alleviate functional deficits induced by a partial nigro-striatal dopamine lesion. This effect may be related to enhanced ventral striatal dopamine activity and/or to the peptide's known effects on learning, motivation, and emotion.
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Affiliation(s)
- S Nikolaus
- Institute for Physiological Psychology I, Heinrich-Heine-University of Düsseldorf, Germany
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