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Dutra-Tavares AC, Souza TP, Silva JO, Semeão KA, Mello FF, Filgueiras CC, Ribeiro-Carvalho A, Manhães AC, Abreu-Villaça Y. Neonatal phencyclidine as a model of sex-biased schizophrenia symptomatology in adolescent mice. Psychopharmacology (Berl) 2023; 240:2111-2129. [PMID: 37530885 DOI: 10.1007/s00213-023-06434-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 07/22/2023] [Indexed: 08/03/2023]
Abstract
Sex-biased differences in schizophrenia are evident in several features of the disease, including symptomatology and response to pharmacological treatments. As a neurodevelopmental disorder, these differences might originate early in life and emerge later during adolescence. Considering that the disruption of the glutamatergic system during development is known to contribute to schizophrenia, we hypothesized that the neonatal phencyclidine model could induce sex-dependent behavioral and neurochemical changes associated with this disorder during adolescence. C57BL/6 mice received either saline or phencyclidine (5, 10, or 20 mg/kg) on postnatal days (PN) 7, 9, and 11. Behavioral assessment occurred in late adolescence (PN48-50), when mice were submitted to the open field, social interaction, and prepulse inhibition tests. Either olanzapine or saline was administered before each test. The NMDAR obligatory GluN1 subunit and the postsynaptic density protein 95 (PSD-95) were evaluated in the frontal cortex and hippocampus at early (PN30) and late (PN50) adolescence. Neonatal phencyclidine evoked dose-dependent deficits in all analyzed behaviors and males were more susceptible. Males also had reduced GluN1 expression in the frontal cortex at PN30. There were late-emergent effects at PN50. Cortical GluN1 was increased in both sexes, while phencyclidine increased cortical and decreased hippocampal PSD-95 in females. Olanzapine failed to mitigate most phencyclidine-evoked alterations. In some instances, this antipsychotic aggravated the deficits or potentiated subthreshold effects. These results lend support to the use of neonatal phencyclidine as a sex-biased neurodevelopmental preclinical model of schizophrenia. Olanzapine null effects and deleterious outcomes suggest that its use during adolescence should be further evaluated.
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Affiliation(s)
- Ana Carolina Dutra-Tavares
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil
| | - Thainá P Souza
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil
| | - Juliana O Silva
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil
| | - Keila A Semeão
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil
| | - Felipe F Mello
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil
| | - Claudio C Filgueiras
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil
| | - Anderson Ribeiro-Carvalho
- Departamento de Ciências, Faculdade de Formação de Professores da Universidade do Estado do Rio de Janeiro (UERJ), RJ, São Gonçalo, Brazil
| | - Alex C Manhães
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil
| | - Yael Abreu-Villaça
- Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Av. Prof. Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ, 20550-170, Brazil.
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Latham LE, Wang C, Patterson TA, Slikker W, Liu F. Neuroprotective Effects of Carnitine and Its Potential Application to Ameliorate Neurotoxicity. Chem Res Toxicol 2021; 34:1208-1222. [PMID: 33570912 DOI: 10.1021/acs.chemrestox.0c00479] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Carnitine is an essential metabolite that is absorbed from the diet and synthesized in the kidney, liver, and brain. It ferries fatty acids across the mitochondrial membrane to undergo β-oxidation. Carnitine has been studied as a therapy or protective agent for many neurological diseases and neurotoxicity (e.g., prolonged anesthetic exposure-induced developmental neurotoxicity in preclinical models). Preclinical and clinical data support the notion that carnitine or acetyl carnitine may improve a patient's quality of life through increased mitochondrial respiration, release of neurotransmitters, and global gene expression changes, showing the potential of carnitine beyond its approved use to treat primary and secondary carnitine deficiency. In this review, we summarize the beneficial effects of carnitine or acetyl carnitine on the central nervous system, highlighting protective effects against neurotoxicity-induced damage caused by various chemicals and encouraging a thorough evaluation of carnitine use as a therapy for patients suffering from neurotoxicant exposure.
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Affiliation(s)
- Leah E Latham
- Division of Neurotoxicology, National Center for Toxicological Research/FDA, Jefferson, Arkansas 72079, United States
| | - Cheng Wang
- Division of Neurotoxicology, National Center for Toxicological Research/FDA, Jefferson, Arkansas 72079, United States
| | - Tucker A Patterson
- Office of Director, National Center for Toxicological Research/FDA, Jefferson, Arkansas 72079, United States
| | - William Slikker
- Office of Director, National Center for Toxicological Research/FDA, Jefferson, Arkansas 72079, United States
| | - Fang Liu
- Division of Neurotoxicology, National Center for Toxicological Research/FDA, Jefferson, Arkansas 72079, United States
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Wang C, Inselman A, Liu S, Liu F. Potential mechanisms for phencyclidine/ketamine-induced brain structural alterations and behavioral consequences. Neurotoxicology 2019; 76:213-219. [PMID: 31812709 DOI: 10.1016/j.neuro.2019.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/24/2019] [Accepted: 12/04/2019] [Indexed: 01/30/2023]
Abstract
Evidence of structural abnormalities in the nervous system of recreational drug [e.g., phencyclidine (PCP) or ketamine] users and/or preclinical animal research models suggests interference with the activity of multiple neurotransmitters, particularly glutamate neurotransmission. The damage to the central nervous system (CNS) may include neuronal loss, synaptic changes, disturbed neural network formation and reduced projections to subcortical fields. Notably, the reduced projections may considerably compromise the establishment of the subcortical areas, such as the nucleus accumbens located in the basal forebrain. With its abundant dopaminergic innervation, the nucleus accumbens is believed to be directly associated with addictive behaviors and mental disorders. This review seeks to delineate the relationship between PCP/ketamine-induced loss of cortical neurons and the reduced level of polysialic acid neural cell adhesion molecule (PSA-NCAM) in the striatum, and the likely changes in striatal synaptogenesis during development. The basic mechanism of how PSA-NCAM cell surface expression may be regulated will also be discussed, as well as the hypothesis that PSA-NCAM activity is critical to the regulation of synaptic protein expression. Overall, the present review will address the general hypothesis that damage/interruption of cortico-striatal communication and subcortical synaptogenesis could underlie the erratic/sensitization or addictive states produced by chronic or prolonged PCP/ketamine usage.
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Affiliation(s)
- Cheng Wang
- Division of Neurotoxicology, National Center for Toxicological Research/U.S. Food & Drug Administration, Jefferson, AR, United States.
| | - Amy Inselman
- Division of Systems Biology, National Center for Toxicological Research/U.S. Food & Drug Administration, Jefferson, AR, United States
| | - Shuliang Liu
- Division of Neurotoxicology, National Center for Toxicological Research/U.S. Food & Drug Administration, Jefferson, AR, United States
| | - Fang Liu
- Division of Neurotoxicology, National Center for Toxicological Research/U.S. Food & Drug Administration, Jefferson, AR, United States.
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Robinson BL, Dumas M, Ali SF, Paule MG, Gu Q, Kanungo J. Mechanistic studies on ketamine-induced mitochondrial toxicity in zebrafish embryos. Neurotoxicol Teratol 2017; 69:63-72. [PMID: 29225006 DOI: 10.1016/j.ntt.2017.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 12/06/2017] [Accepted: 12/06/2017] [Indexed: 12/26/2022]
Abstract
Ketamine, a phencyclidine derivative, is an antagonist of the Ca2+-permeable N-methyl-d-aspartate (NMDA)-type glutamate receptors. It is a pediatric anesthetic and has been implicated in developmental neurotoxicity. Ketamine has also been shown to deplete ATP in mammalian cells. Our previous studies showed that acetyl l-carnitine (ALCAR) prevented ketamine-induced cardiotoxicity and neurotoxicity in zebrafish embryos. Based on our finding that ALCAR's protective effect was blunted by oligomycin A, an inhibitor of ATP synthase, we further investigated the effects of ketamine and ALCAR on ATP levels, mitochondria and ATP synthase in zebrafish embryos. The results demonstrated that ketamine reduced ATP levels in the embryos but not in the presence of ALCAR. Ketamine reduced total mitochondrial protein levels and mitochondrial potential, which were prevented with ALCAR co-treatment. To determine the cause of ketamine-induced ATP deficiency, we explored the status of ATP synthase. The results showed that a subunit of ATP synthase, atp5α1, was transcriptionally down-regulated by ketamine, but not in the presence of ALCAR, although ketamine caused a significant upregulation in another ATP synthase subunit, atp5β and total ATP synthase protein levels. Most of the ATP generated by heart mitochondria are utilized for its contraction and relaxation. Ketamine-treated embryos showed abnormal heart structure, which was abolished with ALCAR co-treatment. This study offers evidence for a potential mechanism by which ketamine could cause ATP deficiency mediated by mitochondrial dysfunction.
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Affiliation(s)
- Bonnie L Robinson
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Melanie Dumas
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Syed F Ali
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Merle G Paule
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Qiang Gu
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Jyotshna Kanungo
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA.
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Guo X, Dumas M, Robinson BL, Ali SF, Paule MG, Gu Q, Kanungo J. Acetyl L-carnitine targets adenosine triphosphate synthase in protecting zebrafish embryos from toxicities induced by verapamil and ketamine: An in vivo assessment. J Appl Toxicol 2016; 37:192-200. [PMID: 27191126 DOI: 10.1002/jat.3340] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 03/31/2016] [Accepted: 03/31/2016] [Indexed: 01/21/2023]
Abstract
Verapamil is a Ca2+ channel blocker and is highly prescribed as an anti-anginal, antiarrhythmic and antihypertensive drug. Ketamine, an antagonist of the Ca2+ -permeable N-methyl-d-aspartate-type glutamate receptors, is a pediatric anesthetic. Previously we have shown that acetyl l-carnitine (ALCAR) reverses ketamine-induced attenuation of heart rate and neurotoxicity in zebrafish embryos. Here, we used 48 h post-fertilization zebrafish embryos that were exposed to relevant drugs for 2 or 4 h. Heart beat and overall development were monitored in vivo. In 48 h post-fertilization embryos, 2 mm ketamine reduced heart rate in a 2 or 4 h exposure and 0.5 mm ALCAR neutralized this effect. ALCAR could reverse ketamine's effect, possibly through a compensatory mechanism involving extracellular Ca2+ entry through L-type Ca2+ channels that ALCAR is known to activate. Hence, we used verapamil to block the L-type Ca2+ channels. Verapamil was more potent in attenuating heart rate and inducing morphological defects in the embryos compared to ketamine at specific times of exposure. ALCAR reversed cardiotoxicity and developmental toxicity in the embryos exposed to verapamil or verapamil plus ketamine, even in the presence of 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester, an inhibitor of intracellular Ca2+ release suggesting that ALCAR acts via effectors downstream of Ca2+ . In fact, ALCAR's protective effect was blunted by oligomycin A, an inhibitor of adenosine triphosphate synthase that acts downstream of Ca2+ during adenosine triphosphate generation. We have identified, for the first time, using in vivo studies, a downstream effector of ALCAR that is critical in abrogating ketamine- and verapamil-induced developmental toxicities. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Xiaoqing Guo
- Division of Neurotoxicology, National Center for Toxicological, Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA.,Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA
| | - Melanie Dumas
- Division of Neurotoxicology, National Center for Toxicological, Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA
| | - Bonnie L Robinson
- Division of Neurotoxicology, National Center for Toxicological, Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA
| | - Syed F Ali
- Division of Neurotoxicology, National Center for Toxicological, Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA
| | - Merle G Paule
- Division of Neurotoxicology, National Center for Toxicological, Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA
| | - Qiang Gu
- Division of Neurotoxicology, National Center for Toxicological, Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA
| | - Jyotshna Kanungo
- Division of Neurotoxicology, National Center for Toxicological, Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA
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Gaskin PLR, Alexander SPH, Fone KCF. Neonatal phencyclidine administration and post-weaning social isolation as a dual-hit model of 'schizophrenia-like' behaviour in the rat. Psychopharmacology (Berl) 2014; 231:2533-45. [PMID: 24402141 DOI: 10.1007/s00213-013-3424-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 12/16/2013] [Indexed: 01/07/2023]
Abstract
RATIONALE Schizophrenia is a debilitating disorder comprising positive, negative and cognitive deficits with a poorly defined neurobiological aetiology; therefore, animal models with greater translational reliability are essential to develop improved therapies. OBJECTIVES This study combines two developmental challenges in rats, neonatal phencyclidine (PCP) injection and subsequent rearing in social isolation from weaning, to attempt to produce more robust behavioural deficits with greater translational relevance to schizophrenia than either challenge alone. METHODS Forty-two male Lister-hooded rat pups received the N-methyl-D-aspartate (NMDA) receptor antagonist, phencyclidine (PCP, 10 mg/kg, s.c.), or vehicle on post-natal day (PND) 7, 9 and 11 and were weaned on PND 23 into group housing (saline-treated n = 11 or PCP-treated n = 10) or isolation (saline n = 10 or PCP n = 11). Six weeks post-weaning, novelty- and PCP-induced (3.2 mg/kg) locomotor activity, novel object discrimination, prepulse inhibition of acoustic startle and contextual memory in a conditioned emotion response (CER) were recorded. RESULTS Isolation rearing alone significantly elevated baseline locomotor activity and induced visual recognition memory impairment in novel object discrimination. Neonatal PCP treatment did not induce locomotor sensitisation to a subsequent acute PCP injection, but it impaired prepulse inhibition when combined with isolation rearing. CER freezing behaviour was significantly reduced by isolation rearing but an even greater effect occurred when combined with neonatal PCP treatment. CONCLUSIONS Neonatal PCP and isolation rearing both produce behavioural deficits in adult rats, but combined treatment caused a wider range of more severe cognitive impairments, providing a more comprehensive preclinical model to determine the neurobiological aetiology of schizophrenia than either treatment alone.
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Affiliation(s)
- Philip L R Gaskin
- School of Life Sciences, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, NG7 2UH, UK
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Cuevas E, Trickler WJ, Guo X, Ali SF, Paule MG, Kanungo J. Acetyl L-carnitine protects motor neurons and Rohon-Beard sensory neurons against ketamine-induced neurotoxicity in zebrafish embryos. Neurotoxicol Teratol 2013; 39:69-76. [PMID: 23896048 DOI: 10.1016/j.ntt.2013.07.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 07/15/2013] [Accepted: 07/16/2013] [Indexed: 12/13/2022]
Abstract
Ketamine, a non-competitive antagonist of N-methyl-D-aspartate (NMDA) type glutamate receptors is commonly used as a pediatric anesthetic. Multiple studies have shown ketamine to be neurotoxic, particularly when administered during the brain growth spurt. Previously, we have shown that ketamine is detrimental to motor neuron development in the zebrafish embryos. Here, using both wild type (WT) and transgenic (hb9:GFP) zebrafish embryos, we demonstrate that ketamine is neurotoxic to both motor and sensory neurons. Drug absorption studies showed that in the WT embryos, ketamine accumulation was approximately 0.4% of the original dose added to the exposure medium. The transgenic embryos express green fluorescent protein (GFP) localized in the motor neurons making them ideal for evaluating motor neuron development and toxicities in vivo. The hb9:GFP zebrafish embryos (28 h post fertilization) treated with 2 mM ketamine for 20 h demonstrated significant reductions in spinal motor neuron numbers, while co-treatment with acetyl L-carnitine proved to be neuroprotective. In whole mount immunohistochemical studies using WT embryos, a similar effect was observed for the primary sensory neurons. In the ketamine-treated WT embryos, the number of primary sensory Rohon-Beard (RB) neurons was significantly reduced compared to that in controls. However, acetyl L-carnitine co-treatment prevented ketamine-induced adverse effects on the RB neurons. These results suggest that acetyl L-carnitine protects both motor and sensory neurons from ketamine-induced neurotoxicity.
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Affiliation(s)
- Elvis Cuevas
- Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA
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Amani M, Samadi H, Doosti MH, Azarfarin M, Bakhtiari A, Majidi-Zolbanin N, Mirza-Rahimi M, Salari AA. Neonatal NMDA receptor blockade alters anxiety- and depression-related behaviors in a sex-dependent manner in mice. Neuropharmacology 2013; 73:87-97. [PMID: 23688920 DOI: 10.1016/j.neuropharm.2013.04.056] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/26/2013] [Accepted: 04/28/2013] [Indexed: 11/29/2022]
Abstract
There is increasing evidence that N-methyl-D-aspartate (NMDA) receptor blockade in the neonatal period has a long-lasting influence on brain and behavior development and has been linked to an increased risk for neuropsychiatric disorders in later life. We sought to determine whether postnatal NMDA receptor blockade can affect normal development of body weight, corticosterone levels, anxiety- and depression-related behaviors in male and female mice in adulthood. For this purpose, male and female NMRI mice were treated with either saline or phencyclidine (PCP; 5 and 10 mg/kg, s.c.) on postnatal days (PND) 7, 9, and 11, and then subjected to different behavioral tests, including open field, elevated plus-maze, elevated zero-maze, light-dark box, tail suspension test and forced swimming test in adulthood. The results indicated that neonatal PCP treatment reduced body weight during neonatal and adulthood periods, and did not alter baseline corticosterone levels in both male and female mice. Moreover, this study obtained some experimental evidence showing the PCP at dose of 10 mg/kg increases stress-induced corticosterone levels, anxiety- and depression-related behaviors in males, while decreasing levels of anxiety without any significant effect on depression in female mice in adulthood. These data support the argument that neonatal NMDA receptor blockade can lead to behavioral abnormalities and psychiatric diseases in adulthood. Collectively, our findings suggest that neonatal exposure to PCP may have profound effects on the development of anxiety- and depression-related behaviors in a sex- and dose-dependent manner in mice.
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Affiliation(s)
- Mohammad Amani
- Department of Physiology, Faculty of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
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L-Carnitine rescues ketamine-induced attenuated heart rate and MAPK (ERK) activity in zebrafish embryos. Reprod Toxicol 2011; 33:205-12. [PMID: 22027688 DOI: 10.1016/j.reprotox.2011.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 10/04/2011] [Accepted: 10/05/2011] [Indexed: 02/07/2023]
Abstract
Ketamine, an antagonist of the N-methyl-D-aspartate (NMDA)-type glutamate receptors, is a pediatric anesthetic. Ketamine has been shown to be neurotoxic and cardiotoxic in mammals. Here, we show that after 2 h of exposure, 5 mM ketamine significantly reduced heart rate in 26 h old zebrafish embryos. In 52 h old embryos, 1 mM ketamine was effective after 2 h and 0.5 mM ketamine at 20 h of exposure. Ketamine also induced significant reductions in activated MAPK (ERK) levels. Treatment of the embryos with the ERK inhibitor, PD 98059, also significantly reduced heart rate whereas the p38/SAPK inhibitor, SB203580, was ineffective. Ketamine is known to inhibit lipolysis and a decrease of ATP content in the heart. Co-treatment with l-carnitine that enhances fatty acid metabolism effectively rescued ketamine-induced attenuated heart rate and ERK activity. These findings demonstrate that l-carnitine counteracts ketamine's negative effects on heart rate and ERK activity in zebrafish embryos.
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Ferguson SA, Law CD, Abshire JS. Developmental Treatment with Bisphenol A or Ethinyl Estradiol Causes Few Alterations on Early Preweaning Measures. Toxicol Sci 2011; 124:149-60. [DOI: 10.1093/toxsci/kfr201] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Gutierrez S, Carnes A, Finucane B, Musci G, Oelsner W, Hicks L, Russell GB, Liu C, Turner CP. Is age-dependent, ketamine-induced apoptosis in the rat somatosensory cortex influenced by temperature? Neuroscience 2010; 168:253-62. [PMID: 20298758 DOI: 10.1016/j.neuroscience.2010.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 02/09/2010] [Accepted: 03/08/2010] [Indexed: 01/18/2023]
Abstract
General anesthetics have long been thought to be relatively safe but recent clinical studies have revealed that exposure of very young children (4 years or less) to agents that act by blocking the N-methyl-D-aspartate receptor (NMDAR) can lead to cognitive deficits as they mature. In rodent and non-human primate studies, blockade of this receptor during the perinatal period leads to a number of molecular, cellular and behavioral pathologies. Despite the overwhelming evidence from such studies, doubt remains as to their clinical relevance. A key issue is whether the primary injury (apoptotic cell death) is specific to receptor blockade or due to non-specific, patho-physiological changes. Principal to this argument is that loss of core body temperature following NMDAR blockade could explain why injury is observed hours later. We therefore examined the neurotoxicity of the general anesthetic ketamine in P7, P14 and P21 rats while monitoring core body temperature. We found that, at P7, ketamine induced the pro-apoptotic enzyme activated caspase-3 in a dose-dependent manner. As expected, injury was greatly diminished by P14 and absent by P21. However, contrary to expectations, we found that core body temperature was not a factor in determining injury. Our data imply that injury is directly related to receptor blockade and is unlikely to be overcome by artificially changing core body temperature.
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Affiliation(s)
- S Gutierrez
- Department of Neurobiology & Anatomy, Wake Forest University School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157-1010, USA
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Developmental neurotoxicity of sedatives and anesthetics: a concern for neonatal and pediatric critical care medicine? Pediatr Crit Care Med 2010; 11:217-26. [PMID: 19770789 DOI: 10.1097/pcc.0b013e3181b80383] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate the currently available evidence for the deleterious effects of sedatives and anesthetics on developing brain structure and neurocognitive function. DESIGN A computerized, bibliographic search of the literature regarding neurodegenerative effects of sedatives and anesthetics in the developing brain. MEASUREMENTS AND MAIN RESULTS A growing number of animal studies demonstrate widespread structural damage of the developing brain and long-lasting neurocognitive abnormalities after exposure to sedatives commonly used in neonatal and pediatric critical care medicine. These studies reveal a dose and exposure time dependence of neuronal cell death, characterize its molecular pathways, and suggest a potential early window of susceptibility in humans. Several clinical studies document neurologic abnormalities in neonatal intensive care unit graduates, usually attributed to comorbidities. Emerging human epidemiologic data, however, do not exclude prolonged or repetitive exposure to sedatives and anesthetics in early childhood as contributing factors to some of these abnormalities. CONCLUSIONS Neuronal cell death after neonatal exposure to sedatives and anesthetics has been clearly demonstrated in developing animal models. Although the relevance for human medicine remains speculative, the phenomenon's serious implications for public health necessitate further preclinical and clinical studies. Intensivists using sedatives and anesthetics in neonates and infants need to stay informed about this rapidly emerging field of research.
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Neonatal exposure to MK801 promotes prepulse-induced delay in startle response time in adult rats. Exp Brain Res 2009; 197:215-22. [PMID: 19565228 DOI: 10.1007/s00221-009-1906-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 06/10/2009] [Indexed: 10/20/2022]
Abstract
The acoustic startle reflex in rats can be inhibited if a prepulse stimulus is presented just before the startle stimulus (prepulse inhibition; PPI). When postnatal day 7 (P7) rats are exposed to agents that block the NMDA receptor (NMDAR), robust apoptosis is observed within hours and is thought to be followed at later ages by a significant loss of PPI. To understand these observations further, we exposed rat pups to vehicle or the NMDAR antagonist MK801 (1 mg/kg) at P6, P8, and P10. We then examined animals for PPI at P28 and P56. Compared to vehicle controls, we found no evidence for PPI deficits in the MK801-treated group, although we did observe prepulse-induced delay in response time at P56 (but not at P28). In a parallel study, we also performed histological analysis of brain sections for evidence of the pro-apoptotic marker activated caspase-3, 8 h after vehicle or MK801 injection into P6 animals. We found that there was a robust increase in this marker of cell death in the inferior colliculus of MK801 compared to vehicle-treated animals. Thus, transient blockade of the NMDAR during the postnatal period not only promotes early apoptosis in a brain region critical for acoustic processing but also leads to auditory deficits at a later age, suggesting that injury-induced loss of collicular neurons leads to network reorganization in the auditory system that is progressive in nature.
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Boctor SY, Ferguson SA. Neonatal NMDA receptor antagonist treatments have no effects on prepulse inhibition of postnatal day 25 Sprague-Dawley rats. Neurotoxicology 2008; 30:151-4. [PMID: 19038286 DOI: 10.1016/j.neuro.2008.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/29/2008] [Accepted: 10/29/2008] [Indexed: 11/29/2022]
Abstract
Glutamate activation of the NMDA receptor is essential for neuronal differentiation, migration, and survival. Treatment with NMDA receptor antagonists, such as ketamine (KET) or phencyclidine (PCP), can trigger apoptosis in neonatal rats. However, L-carnitine (LC) treatment appears to prevent glutamate-induced toxicity in the developing CNS. Previously, we described altered preweaning behaviors (i.e., abnormal home cage, slant board and forelimb hang behaviors) resulting from neonatal PCP and KET treatment. Those adverse effects of KET were somewhat ameliorated by LC [Boctor SY, Wang C, Ferguson SA. Neonatal PCP is more potent than ketamine at modifying preweaning behaviors of Sprague-Dawley rats. Toxicol Sci 2008;106:172-9]. Here, a portion of those subjects were evaluated for prepulse inhibition (PPI) of the acoustic startle response at postnatal day (PND) 25 since previous reports described PCP-induced effects on this response. Rats were subcutaneously treated with: saline; 10 mg/kg PCP (1x/day) on PNDs 7, 9 and 11; 20 mg/kg KET (6 injections every 2h on PND 7); or a similar regimen of ketamine and 250 mg/kg LC on PND 7, with a single injection of 250 mg/kg LC on PNDs 8-11 (KLC). Male and female rats were assessed using a standard PPI paradigm with prepulses of 68, 78 and 82 dB. Body weight was decreased 17-21% and whole brain weight was decreased 10% in PCP-treated rats. Specifically, cerebellar weight was significantly less in PCP-treated rats relative to control. Despite the magnitude of those PCP-induced changes, startle response in normal pulse only trials and percent of PPI in PCP-, KET-, and KLC-treated groups were comparable to controls. Average latency to maximum startle was 2.6 ms less in females than males (p<0.007); there were no other significant sex effects. The lack of neonatal PCP treatment on later PPI is similar to that reported by Rasmussen et al. [Rasmussen BA, O'Neil J, Manaye KF, Perry DC, Tizabi Y. Long-term effects of developmental PCP administration on sensorimotor gating in male and female rats. Psychopharmacology (Berl) 2007; 190: 43-9.], and indicates that neonatal PCP-induced effects on PPI [Wang C, McInnis J, Ross-Sanchez M, Shinnick-Gallagher P, Wiley JL, Johnson KM. Long-term behavioral and neurodegenerative effects of perinatal phencyclidine administration: implications for schizophrenia. Neuroscience 2001; 107: 535-50.] appear difficult to replicate.
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Affiliation(s)
- Sherin Y Boctor
- Department of Interdisciplinary Biomedical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
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Response to the comment on Viberg et al. (2008) “Neonatal ketamine exposure results in changes in biochemical substrates of neuronal growth and synaptogenesis, and alters adult behavior irreversibly” by Ching-Hung Hsu. Toxicology 2008. [DOI: 10.1016/j.tox.2008.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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