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Ahmed N, Kassis A, Malone J, Yang J, Zamzami E, Lin AH, Gordon SM, Gong M, Bardo M, Dalmasso C, Loria AS. Prenatal Morphine Exposure Increases Cardiovascular Disease Risk and Programs Neurogenic Hypertension in the Adult Offspring. Hypertension 2023; 80:1283-1296. [PMID: 37042247 PMCID: PMC10274123 DOI: 10.1161/hypertensionaha.122.20262] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/20/2023] [Indexed: 04/13/2023]
Abstract
BACKGROUND The opioid overdose and opioid use disorder epidemics are concomitant with increased metabolic and CVD risk. Although opioid use disorder causes adverse pregnancy outcomes, the offspring's cardiovascular health is understudied. We hypothesized that offspring exposed to in utero morphine exposure (IUME) would show increased CVD risk factors and endogenous opioid system dysregulation. METHODS Sprague Dawley dams were treated with saline (vehicle, n=10) or escalating doses of morphine (5-20 mg/kg per day, SC, n=10) during gestation. Cardiovascular and metabolic parameters were assessed in adult offspring. RESULTS Litter size and pups' birth weight were not different in response to IUME. Female and male IUME offspring showed reduced body length at birth (P<0.05) and body weight from weeks 1 to 3 of life (P<0.05), followed by a catch-up growth effect. By week 16, female and male IUME rats showed reduced tibia length (P<0.05) and fat mass. IUME increases the mean arterial pressure and the depressor response to mecamylamine (5 mg/kg per day, IP) induced by IUME were abolished by a chronic treatment with an alpha-adrenergic receptor blocker (prazosin; 1 mg/kg per day, IP). Although circulating levels of angiotensin peptides were similar between groups, IUME exacerbated maximal ex vivo Ang (angiotensin) II-induced vasoconstriction (P<0.05) and induced endothelial dysfunction in a sex-specific manner (P<0.05). Proenkephalin, an endogenous opioid peptide that lowers blood pressure and sympathetic-mediated vasoconstriction, showed reduced mRNA expression in the heart, aorta, and kidneys from morphine versus vehicle group (P<0.05). CONCLUSIONS Among the effects of IUME, neurogenic hypertension, vascular dysfunction, and metabolic dysfunction could be associated with the dysregulation of the endogenous opioid system.
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Affiliation(s)
- Nermin Ahmed
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Alana Kassis
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Jena Malone
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Jodie Yang
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Esraa Zamzami
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - An-Hsuan Lin
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Scott M. Gordon
- SAHA Cardiovascular Center, University of Kentucky, Lexington, KY 40536
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Ming Gong
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Michael Bardo
- Department of Psychology, College of Arts and Sciences, University of Kentucky, Lexington, KY 40536
| | - Carolina Dalmasso
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536
| | - Analia S. Loria
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536
- SAHA Cardiovascular Center, University of Kentucky, Lexington, KY 40536
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Olmsted ZT, Paluh JL. Co-development of central and peripheral neurons with trunk mesendoderm in human elongating multi-lineage organized gastruloids. Nat Commun 2021; 12:3020. [PMID: 34021144 PMCID: PMC8140076 DOI: 10.1038/s41467-021-23294-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/20/2021] [Indexed: 02/04/2023] Open
Abstract
Stem cell technologies including self-assembling 3D tissue models provide access to early human neurodevelopment and fundamental insights into neuropathologies. Gastruloid models have not been used to investigate co-developing central and peripheral neuronal systems with trunk mesendoderm which we achieve here in elongating multi-lineage organized (EMLO) gastruloids. We evaluate EMLOs over a forty-day period, applying immunofluorescence of multi-lineage and functional biomarkers, including day 16 single-cell RNA-Seq, and evaluation of ectodermal and non-ectodermal neural crest cells (NCCs). We identify NCCs that differentiate to form peripheral neurons integrated with an upstream spinal cord region after day 8. This follows initial EMLO polarization events that coordinate with endoderm differentiation and primitive gut tube formation during multicellular spatial reorganization. This combined human central-peripheral nervous system model of early organogenesis highlights developmental events of mesendoderm and neuromuscular trunk regions and enables systemic studies of tissue interactions and innervation of neuromuscular, enteric and cardiac relevance.
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Affiliation(s)
- Zachary T Olmsted
- State University of New York Polytechnic Institute, College of Nanoscale Science and Engineering, Nanobioscience Constellation, Albany, NY, USA
| | - Janet L Paluh
- State University of New York Polytechnic Institute, College of Nanoscale Science and Engineering, Nanobioscience Constellation, Albany, NY, USA.
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3
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Harder HJ, Murphy AZ. Early life opioid exposure and potential long-term effects. Neurobiol Stress 2019; 10:100156. [PMID: 31338390 PMCID: PMC6629922 DOI: 10.1016/j.ynstr.2019.100156] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/13/2019] [Accepted: 03/08/2019] [Indexed: 11/09/2022] Open
Abstract
The long-term consequences of perinatal opioid exposure and subsequent development of neonatal opioid withdrawal syndrome is largely unknown and likely dependent on a multitude of factors, including co-morbid drug use, pre- and post-natal care, and individual factors including the maternal-infant relationship and home environment. This review summarizes the current literature from clinical and preclinical studies on perinatal opioid exposure, focusing on the consequences in the offspring. Although a large number of preclinical studies have been conducted examining the impact of prenatal opioid exposure, the models employed are not necessarily representative of clinical use patterns, making it challenging to translate these results to the impacted population. Use of more clinically-relevant models of perinatal opioid exposure are requisite for the development of improved pharmacological and behavioral treatment strategies to improve quality of life for this vulnerable population.
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Affiliation(s)
| | - Anne Z. Murphy
- Neuroscience Institute, Georgia State University, Atlanta, GA, 30308, USA
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Samir S, Yllanes AP, Lallemand P, Brewer KL, Clemens S. Morphine responsiveness to thermal pain stimuli is aging-associated and mediated by dopamine D1 and D3 receptor interactions. Neuroscience 2017; 349:87-97. [PMID: 28257894 DOI: 10.1016/j.neuroscience.2017.02.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 01/16/2017] [Accepted: 02/20/2017] [Indexed: 01/09/2023]
Abstract
Morphine actions involve the dopamine (DA) D1 and D3 receptor systems (D1R and D3R), and the responses to morphine change with age. We here explored in differently aged wild-type (WT) and D3R knockout mice (D3KO) the interactions of the D1R/D3R systems with morphine in vivo at three different times of the animals' lifespan (2months, 1year, and 2years). We found that: (1) thermal pain withdrawal reflexes follow an aging-associated phenotype, with relatively longer latencies at 2months and shorter latencies at 1year, (2) over the same age range, a dysfunction of the D3R subtype decreases reflex latencies more than aging alone, (3) morphine altered reflex responses in a dose-dependent manner in WT animals and changed at its higher dose the phenotype of the D3KO animals from a morphine-resistant state to a morphine-responsive state, (4) block of D1R function had an aging-dependent effect on thermal withdrawal latencies in control animals that, in old animals, was stronger than that of low-dose morphine. Lastly, (5) block of D1R function in young D3KO animals mimicked the behavioral phenotype observed in the aged WT. Our proof-of-concept data from the rodent animal model suggest that, with age, block of D1R function may be considered as an alternative to the use of morphine, to modulate the response to painful stimuli.
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Affiliation(s)
- Sophia Samir
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Alexander P Yllanes
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Perrine Lallemand
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Kori L Brewer
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, United States.
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5
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Tadros MA, Lim R, Hughes DI, Brichta AM, Callister RJ. Electrical maturation of spinal neurons in the human fetus: comparison of ventral and dorsal horn. J Neurophysiol 2015; 114:2661-71. [PMID: 26334015 DOI: 10.1152/jn.00682.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/26/2015] [Indexed: 11/22/2022] Open
Abstract
The spinal cord is critical for modifying and relaying sensory information to, and motor commands from, higher centers in the central nervous system to initiate and maintain contextually relevant locomotor responses. Our understanding of how spinal sensorimotor circuits are established during in utero development is based largely on studies in rodents. In contrast, there is little functional data on the development of sensory and motor systems in humans. Here, we use patch-clamp electrophysiology to examine the development of neuronal excitability in human fetal spinal cords (10-18 wk gestation; WG). Transverse spinal cord slices (300 μm thick) were prepared, and recordings were made, from visualized neurons in either the ventral (VH) or dorsal horn (DH) at 32°C. Action potentials (APs) could be elicited in VH neurons throughout the period examined, but only after 16 WG in DH neurons. At this age, VH neurons discharged multiple APs, whereas most DH neurons discharged single APs. In addition, at 16-18 WG, VH neurons also displayed larger AP and after-hyperpolarization amplitudes than DH neurons. Between 10 and 18 WG, the intrinsic properties of VH neurons changed markedly, with input resistance decreasing and AP and after-hyperpolarization amplitudes increasing. These findings are consistent with the hypothesis that VH motor circuitry matures more rapidly than the DH circuits that are involved in processing tactile and nociceptive information.
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Affiliation(s)
- M A Tadros
- School of Biomedical Sciences & Pharmacy, Faculty of Health and Medicine, Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
| | - R Lim
- School of Biomedical Sciences & Pharmacy, Faculty of Health and Medicine, Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
| | - D I Hughes
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - A M Brichta
- School of Biomedical Sciences & Pharmacy, Faculty of Health and Medicine, Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
| | - R J Callister
- School of Biomedical Sciences & Pharmacy, Faculty of Health and Medicine, Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
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Brewer KL, Baran CA, Whitfield BR, Jensen AM, Clemens S. Dopamine D3 receptor dysfunction prevents anti-nociceptive effects of morphine in the spinal cord. Front Neural Circuits 2014; 8:62. [PMID: 24966815 PMCID: PMC4052813 DOI: 10.3389/fncir.2014.00062] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/23/2014] [Indexed: 01/11/2023] Open
Abstract
Dopamine (DA) modulates spinal reflexes, including nociceptive reflexes, in part via the D3 receptor subtype. We have previously shown that mice lacking the functional D3 receptor (D3KO) exhibit decreased paw withdrawal latencies from painful thermal stimuli. Altering the DA system in the CNS, including D1 and D3 receptor systems, reduces the ability of opioids to provide analgesia. Here, we tested if the increased pain sensitivity in D3KO might result from a modified μ-opioid receptor (MOR) function at the spinal cord level. As D1 and D3 receptor subtypes have competing cellular effects and can form heterodimers, we tested if the changes in MOR function may be mediated in D3KO through the functionally intact D1 receptor system. We assessed thermal paw withdrawal latencies in D3KO and wild type (WT) mice before and after systemic treatment with morphine, determined MOR and phosphorylated MOR (p-MOR) protein expression levels in lumbar spinal cords, and tested the functional effects of DA and MOR receptor agonists in the isolated spinal cord. In vivo, a single morphine administration (2 mg/kg) increased withdrawal latencies in WT but not D3KO, and these differential effects were mimicked in vitro, where morphine modulated spinal reflex amplitudes (SRAs) in WT but not D3KO. Total MOR protein expression levels were similar between WT and D3KO, but the ratio of pMOR/total MOR was higher in D3KO. Blocking D3 receptors in the isolated WT cord precluded morphine's inhibitory effects observed under control conditions. Lastly, we observed an increase in D1 receptor protein expression in the lumbar spinal cord of D3KO. Our data suggest that the D3 receptor modulates the MOR system in the spinal cord, and that a dysfunction of the D3 receptor can induce a morphine-resistant state. We propose that the D3KO mouse may serve as a model to study the onset of morphine resistance at the spinal cord level, the primary processing site of the nociceptive pathway.
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Affiliation(s)
- Kori L Brewer
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Christine A Baran
- Department of Emergency Medicine, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Brian R Whitfield
- Department of Emergency Medicine, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - A Marley Jensen
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
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7
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Niknam NA, Azarnia M, Bahadoran H, Kazemi M, Tekieh E, Ranjbaran M, Sahraei H. Evaluating the effects of oral morphine on embryonic development of cerebellum in wistar rats. Basic Clin Neurosci 2013; 4:130-5. [PMID: 25337339 PMCID: PMC4202532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 02/04/2013] [Accepted: 02/15/2013] [Indexed: 11/06/2022] Open
Abstract
In the present research, the effect of morphine consumption during pregnancy on the development of the embryo's spinal cord was studied in Wistar rat. FEMALE WISTAR RATS (WT 250-300 g) were mated with males. The test group received morphine (0.01 mg/ml) in their drinking water. Pregnant rats were later killed with chloroform on the 12th, 13th and 14th days of pregnancy, and the embryos were taken out surgically. The embryos were fixed in formalin 10% for 2 weeks. Then, the weight of fixed embryos was calculated by a scale. In addition, several animals' sizes including fronto-posterior and lateral length were measured by a caliper. Tissue processing, sectioning and hematoxylin and eosin (H&E) staining were applied for the embryos. The sections were examined for spinal cord development by light microscope and MOTIC software. Significant decrease was observed in the fronto-posterior and lateral length and the weight of the embryos in the test groups. The thickness of the white matter layer decreased on the 12th, 13th and 14th embryonic days. The thickness of the spine's grey layer was also less than the control group, on the same days. Increase in the length of the ependimal duct observed as well. Number of grey substance cells decreased compared to the control group within the same days. Meanwhile, thickness of the germinal layer reduced in comparison to the control group on the mentioned days. In conclusion, morphine consumption during pregnancy causes defects in growth and completion of the spinal cord.
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Affiliation(s)
- Narges A. Niknam
- Department of Biology, School of Science, Tehran North Branch, Islamic Azad University, Tehran, Iran
| | - Mahnaz Azarnia
- Department of Biology, School of Science, Kharazmi University, Tehran, Iran
| | - Hossein Bahadoran
- Department of Anatomy, Faculty of Medicine, Baqiyatallah (a.s.) University of Medical Sciences, Tehran, Iran
| | - Masoomeh Kazemi
- Neuroscience Research Center, Baqiyatallah (a.s.) University of Medical Sciences, Tehran, Iran
| | - Elaheh Tekieh
- Neuroscience Research Center, Baqiyatallah (a.s.) University of Medical Sciences, Tehran, Iran
| | - Mina Ranjbaran
- Neuroscience Research Center, Baqiyatallah (a.s.) University of Medical Sciences, Tehran, Iran
| | - Hedayat Sahraei
- Neuroscience Research Center, Baqiyatallah (a.s.) University of Medical Sciences, Tehran, Iran,Corresponding Author: Hedyat Sahraei, PhD, Department of Physiology and Biophysics, School of Medicine, Baqiyatallah (a.s.) University of Medical Sciences, Tehran, Iran. P.O.Box: 19395-6558, Tel & Fax: (+9821)2612725. E-mail:
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8
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Thorpe AJ, Clair A, Hochman S, Clemens S. Possible Sites of Therapeutic Action in Restless Legs Syndrome: Focus on Dopamine and α 2δ Ligands. Eur Neurol 2011; 66:18-29. [DOI: 10.1159/000328431] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 04/11/2011] [Indexed: 01/01/2023]
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Fitting S, Zou S, Chen W, Vo P, Hauser KF, Knapp PE. Regional heterogeneity and diversity in cytokine and chemokine production by astroglia: differential responses to HIV-1 Tat, gp120, and morphine revealed by multiplex analysis. J Proteome Res 2010; 9:1795-804. [PMID: 20121167 DOI: 10.1021/pr900926n] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
HIV-infected individuals who abuse opiates show a faster progression to AIDS and higher incidence of encephalitis. The HIV-1 proteins Tat and gp120 have been shown to cause neurodegenerative changes either in vitro or when injected or expressed in the CNS, and we have shown that opiate drugs can exacerbate neurotoxic effects in the striatum through direct actions on pharmacologically discrete subpopulations of mu-opioid receptor-expressing astroglia. Opiate coexposure also significantly enhances release of specific inflammatory mediators by astroglia from the striatum, and we theorize that astroglial reactivity may underlie aspects of HIV neuropathology. To determine whether astroglia from different regions of the central nervous system have distinct, intrinsic responses to HIV-1 proteins and opiates, we used multiplex suspension array analyses to define and compare the inflammatory signature of cytokines released by murine astrocytes grown from cerebral cortex, cerebellum, and spinal cord. Results demonstrate significant regional differences in baseline secretion patterns, and in responses to viral proteins. Of importance for the disease process, astrocytes from all regions have very limited inflammatory response to gp120 protein, as compared to Tat protein, either in the presence or absence of morphine. Overall, the chemokine/cytokine release is higher from spinal cord and cortical astroglia than from cerebellar astroglia, paralleling the relatively low incidence of HIV-related neuropathology in the cerebellum.
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Affiliation(s)
- Sylvia Fitting
- Department of Anatomy and Neurobiology, Department of Pharmacology and Toxicology, and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia 23298-0709, USA
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Schmid M, Kuessel L, Klein K, Metz V, Fischer G, Krampl-Bettelheim E. First-trimester fetal heart rate in mothers with opioid addiction. Addiction 2010; 105:1265-8. [PMID: 20642509 DOI: 10.1111/j.1360-0443.2010.02982.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIM To investigate the difference in fetal heart rate of opioid-dependent mothers compared to non-dependent mothers in the first trimester of pregnancy. DESIGN The data of 74 consecutive singleton pregnancies of mothers enrolled in a maintenance programme for opioid-dependent women was matched to 74 non-exposed singleton pregnancies by maternal age, crown-rump length, smoking status, ethnic background and mode of conception. MEASUREMENT Fetal heart rate measured as part of first-trimester screening by Doppler ultrasound between 11+0 and 13+6 gestational weeks was compared retrospectively. FINDINGS The mean fetal heart rate in opioid-dependent mothers was 156.0 beats per minute (standard deviation 7.3) compared to 159.6 (6.5) in controls. The difference in fetal heart rate was significant (P = 0.02). There was a significant difference in mean maternal body mass index (P = 0.01) but not in mean nuchal translucency (P = 0.3), gestational age (0.5), fetal gender (P = 0.3) and parity (P = 0.3) between both groups. Fifty-five per cent (41 of 74) of cases were taking methadone, 30% (22 of 74) buprenorphine and 15% (11 of 74) were taking slow-release morphines throughout the pregnancy. CONCLUSIONS In fetuses of opioid-dependent mothers a decreased fetal heart rate can already be observed between 11+0 and 13+6 gestational weeks. The effect of opioid intake needs to be taken into consideration when interpreting fetal heart rate in opioid-dependent mothers at first-trimester screening.
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Affiliation(s)
- Maximilian Schmid
- Department of Obstetrics and Feto-maternal Medicine, Medical University of Vienna, A-1090 Vienna, Austria.
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Maternal Oral Consumption of Morphine Increases Bax/Bcl-2 Ratio and Caspase 3 Activity During Early Neural System Development in Rat Embryos. J Mol Neurosci 2009; 41:156-64. [DOI: 10.1007/s12031-009-9312-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 11/03/2009] [Indexed: 12/19/2022]
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Ray SB, Gupta H, Gupta YK. Up-regulation of mu-opioid receptors in the spinal cord of morphine-tolerant rats. J Biosci 2009; 29:51-6. [PMID: 15286403 DOI: 10.1007/bf02702561] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Though morphine remains the most powerful drug for treating pain, its effectiveness is limited by the development of tolerance and dependence. The mechanism underlying development of tolerance to morphine is still poorly understood. One of the factors could be an alteration in the number of micro-receptors within specific parts of the nervous system. However, reports on changes in the micro-opioid receptor density in the spinal cord after chronic morphine administration are conflicting. Most of the studies have used subcutaneously implanted morphine pellets to produce tolerance. However, it does not simulate clinical conditions, where it is more common to administer morphine at intervals, either by injections or orally. In the present study, rats were made tolerant to morphine by injecting increasing doses of morphine (10-50 mg/kg, subcutaneously) for five days. In vitro tissue autoradiography for localization of micro-receptor in the spinal cord was done using [3H]-DAMGO. As compared to the spinal cord of control rats, the spinal cord of tolerant rats showed an 18.8% increase or up-regulation in the density of micro-receptors in the superficial layers of the dorsal horn. This up-regulation of micro-receptors after morphine tolerance suggests that a fraction of the receptors have been rendered desensitized, which in turn could lead to tolerance
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Affiliation(s)
- Subrata Basu Ray
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
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Developmental expression and distribution of opioid receptors in zebrafish. Neuroscience 2007; 151:129-37. [PMID: 18082336 DOI: 10.1016/j.neuroscience.2007.09.086] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 09/24/2007] [Accepted: 10/27/2007] [Indexed: 11/22/2022]
Abstract
Zebrafish is a novel experimental model that has been used in developmental studies as well as in the study of pathological processes involved in human diseases. It has been demonstrated that the endogenous opioid system is involved in developmental mechanisms. We have studied the relationship between the different embryonic stages and opioid receptor expression for the four known opioid receptors in zebrafish (mu, delta 1, delta 2 and kappa). The mu opioid receptor is detected at higher levels than the other opioid receptors before the midblastula transition and during the segmentation period. The delta duplicate 2 exhibits only one peak of expression at 21 h postfertilization (hpf), when the motor nervous system is forming. The kappa receptor is expressed at very low levels. In situ hybridization studies at 24 hpf show that the opioid receptors are widely distributed in zebrafish CNS and at 48 hpf their localization is detected in more defined structures. Our results support specific implications of the opioid receptors in developmental processes such as morphogenesis of the CNS, neurogenesis, neuroprotection and development of neuromuscular and digestive system. Pain-related alterations can be a consequence of changes in the endogenous opioid system during development, hence we provide important information that might help to solve pain-related pathological situations.
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Nasiraei-Moghadam S, Sahraei H, Bahadoran H, Sadooghi M, Salimi SH, Kaka GR, Imani H, Mahdavi-Nasab H, Dashtnavard H. Effects of maternal oral morphine consumption on neural tube development in Wistar rats. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 159:12-7. [PMID: 16054236 DOI: 10.1016/j.devbrainres.2005.06.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2005] [Revised: 05/28/2005] [Accepted: 06/01/2005] [Indexed: 11/18/2022]
Abstract
Opiate abuse during pregnancy may result in abnormal nervous system function. In order to evaluate the effects of morphine on the development of the nervous system, the present study focused on the effects of maternal morphine consumption on neural tube development in Wistar rats. Female Wistar rats (250-300 g) were crossed with male rats and coupling time was recorded (embryonic day 0-E0). Experimental groups received 0.1, 0.05, and 0.01 mg/ml of morphine in drinking water daily (14 ml water for each rat). Control group received tap water. On embryonic day 9.5 (E9.5), the animals were anesthetized and the embryos were surgically removed. The embryos were fixed in 10% formalin for 1 week. After this time, weights and lengths (antero-posterior axis--A-P) of the embryos were determined and then tissues were processed, sectioned, and stained in hematoxylin and eosin (H&E). The sections were investigated for neural tube development by light microscope and MOTIC software. The decrease in "A-P" length and embryonic weight for the group that received 0.01 mg/ml morphine was significant. It seems that daily consumption of morphine sulfate could delay neural tube development. In addition, administration of 0.01 mg/ml of morphine led to damage to the regulated neuro-ectoderm layer and its thickness. This study showed that oral morphine consumption leads to neural tube defects, as indicated in the morphometric change and also reduction in weight and length of the embryos. These defects might affect the behavior of the animals.
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Sandman CA, Glynn L, Wadhwa PD, Chicz-DeMet A, Porto M, Garite T. Maternal hypothalamic-pituitary-adrenal disregulation during the third trimester influences human fetal responses. Dev Neurosci 2003; 25:41-9. [PMID: 12876430 DOI: 10.1159/000071467] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2002] [Accepted: 02/07/2003] [Indexed: 11/19/2022] Open
Abstract
Maternal peptides from the hypothalamic-pituitary-adrenal (HPA) axis rise during human pregnancy. The effects of circulating maternal adrenocorticotropin (ACTH) and beta-endorphin (BE) on human fetal behavior was determined in 135 women during their 32nd week of gestation. Fetal behavior was measured by assessing heart rate habituation to a series of repeated vibroacoustic stimuli. Individual differences in habituation were determined by computing the number of consecutive responses above the standard deviation during a control period. There was no significant relation between levels of ACTH, BE and the rate of fetal heart rate habituation. However, an index of HPA disregulation (uncoupling of ACTH and BE) was related significantly to fetal behavior. Fetal exposure to high levels of maternal BE relative to ACTH was associated with significantly lower rates of habituation. Results indicate that maternal stress and stress-related peptides influence fetal response patterns. It is possible that this influence persists over the life span.
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Affiliation(s)
- Curt A Sandman
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA.
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Beland B, Fitzgerald M. Mu- and delta-opioid receptors are downregulated in the largest diameter primary sensory neurons during postnatal development in rats. Pain 2001; 90:143-50. [PMID: 11166980 DOI: 10.1016/s0304-3959(00)00397-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of this study was to investigate the postnatal development of mu-(MOR) and delta-opioid receptor (DOR) immunoreactivity in rat dorsal root ganglia. Lumbar dorsal root ganglia (DRG) from postnatal day (P) 0, 3, 7 and 21 rat pups were immunostained for MOR and DOR. Proportions of MOR +ve and DOR +ve cells were calculated from profile counts. Diameters of MOR +ve and DOR +ve cells were measured and compared to -ve cells. The coexpression of MOR and neurofilament (NF200) in DRG over this postnatal period was also investigated. A greater proportion of cells were immunoreactive for MOR and DOR in neonatal rat DRG at P0, P3 and P7 compared to P21. At P3, 39.5+/-1.7% of cells were MOR +ve and 30.3+/-1.5% were DOR +ve, whereas at P21, the values were 30.1+/-1.7% and 21.8+/-1.6% (mean+/-SEM), respectively. During the first postnatal week both opioid receptors were expressed in cells across the whole diameter range but by 3 weeks of age, expression was restricted to small and medium diameter cells. Furthermore, a significantly higher proportion of NF200 +ve cells expressed MOR in new-born compared to P21 rats. The results show that MOR and DOR expression is downregulated in the largest diameter, NF200 +ve primary sensory neurons postnatally. Since these neurons are mainly non-nociceptive, this may explain previous reports of opioid agonists affecting reflex responses to both innocuous and noxious stimuli in rat pups. The results highlight an important difference between opioid function in the immature and adult nervous system.
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Affiliation(s)
- B Beland
- Department of Anatomy and Developmental Biology, University College London, Gower Street, WC1E 6BT, London, UK
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Abstract
This paper is the twenty-second installment of the annual review of research concerning the opiate system. It summarizes papers published during 1999 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; learning, memory, and reward; eating and drinking; alcohol and other drugs of abuse; sexual activity, pregnancy, and development; mental illness and mood; seizures and other neurologic disorders; electrical-related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregulation; and immunologic responses.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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