1
|
Intermittent access cocaine self-administration produces psychomotor sensitization: effects of withdrawal, sex and cross-sensitization. Psychopharmacology (Berl) 2020; 237:1795-1812. [PMID: 32206828 PMCID: PMC7244391 DOI: 10.1007/s00213-020-05500-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/28/2020] [Indexed: 02/05/2023]
Abstract
RATIONALE With repeated administration, the psychomotor activating effects of drugs such as cocaine or amphetamine can change in very different ways-showing sensitization or tolerance-depending on whether they are administered more or less intermittently. This behavioral plasticity is thought to reflect, at least in part, changes in dopamine (DA) neurotransmission, and therefore, may provide insights into the development of substance use disorders. Indeed, the most widely used preclinical model of cocaine addiction, which involves Long Access (LgA) self-administration procedures, is reported to produce tolerance to cocaine's psychomotor activating effects and effects on DA activity. In contrast, Intermittent Access (IntA) cocaine self-administration is more effective than LgA in producing addiction-like behavior, but sensitizes DA neurotransmission. There is, however, very little information concerning the effects of IntA experience on the psychomotor activating effects of cocaine. OBJECTIVE The objective of this study was to determine whether IntA experience produces psychomotor sensitization with similar characteristics to that produced by the intermittent, noncontingent administration of cocaine. RESULTS IntA to cocaine did indeed produce psychomotor sensitization that (1) was greater after a long (30 days) vs. short (1 day) period of withdrawal, (2) was greater in females than males, and (3) resulted in cross-sensitization to another psychomotor stimulant drug, amphetamine. CONCLUSION The tolerance sometimes associated with LgA cocaine self-administration has been cited in support of the idea that, in addiction, drug-seeking and drug-taking is motivated to overcome a DA deficiency and associated anhedonia. In contrast, the neurobehavioral sensitization associated with IntA cocaine self-administration favors an incentive-sensitization view.
Collapse
|
2
|
Marie N, Canestrelli C, Noble F. Role of pharmacokinetic and pharmacodynamic parameters in neuroadaptations induced by drugs of abuse, with a focus on opioids and psychostimulants. Neurosci Biobehav Rev 2019; 106:217-226. [DOI: 10.1016/j.neubiorev.2018.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/29/2018] [Accepted: 06/06/2018] [Indexed: 01/16/2023]
|
3
|
Trujillo KA, Heller CY. Ketamine sensitization: Influence of dose, environment, social isolation and treatment interval. Behav Brain Res 2019; 378:112271. [PMID: 31593791 DOI: 10.1016/j.bbr.2019.112271] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/12/2019] [Accepted: 09/30/2019] [Indexed: 12/18/2022]
Abstract
Ketamine is a dissociative anesthetic first developed in the 1960s but is increasingly used at subanesthetic doses for both clinical and non-clinical purposes. There is evidence from human recreational users of compulsive use and addiction. Sensitization is an increase in an effect of a drug with repeated use that is thought to be important in the development of addiction. Research on psychomotor stimulants has shown the development of sensitization in laboratory animals to be modified by factors that influence addiction. In the current paper we describe four experiments on the development of sensitization in laboratory rats aimed at determining if ketamine sensitization is also influenced by factors thought to be important in addiction. Adult, male Sprague-Dawley rats received ketamine (5, 10, 20 or 50 mg/kg i.p.) for five or more days and the development of locomotor sensitization was followed. Experiment 1 examined the ability of low doses of ketamine to produce sensitization and found sensitization at 5, 10 and 20 mg/kg. Experiment 2 examined the influence of environmental context and found that ketamine sensitization (20 mg/kg) was greater when administration occurred in a novel environment (the experimental apparatus) than in home cages. Experiment 3 found that ketamine sensitization (20 mg/kg) did not occur when animals were housed in social isolation but occurred readily in pair-housed animals. Finally, Experiment 4 found that ketamine sensitization (20 or 50 mg/kg) was similar whether drug was administered daily or at 3-day intervals. Together, the results demonstrate that ketamine sensitization is robust and reliable, occurring under a variety of circumstances. Moreover, ketamine sensitization is influenced by factors that influence the development of addiction in humans. The current results may lead to a better understanding of ketamine abuse and addiction and may help inform clinical use of the drug.
Collapse
Affiliation(s)
- Keith A Trujillo
- Department of Psychology and Office for Training, Research, and Education in the Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096-0001, USA.
| | - Colleen Y Heller
- Department of Psychology and Office for Training, Research, and Education in the Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096-0001, USA
| |
Collapse
|
4
|
Nona CN, Hendershot CS, Lê AD. Behavioural sensitization to alcohol: Bridging the gap between preclinical research and human models. Pharmacol Biochem Behav 2018; 173:15-26. [DOI: 10.1016/j.pbb.2018.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 07/31/2018] [Accepted: 08/07/2018] [Indexed: 12/28/2022]
|
5
|
Hendershot CS, Nona CN. A Review of Developmental Considerations in Human Laboratory Alcohol Research. CURRENT ADDICTION REPORTS 2017; 4:364-378. [PMID: 29326866 DOI: 10.1007/s40429-017-0173-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE OF REVIEW Human laboratory studies involving alcohol administration have generated critical knowledge about individual differences in risk for alcohol use disorder (AUD), but have primarily involved adult populations and cross-sectional research designs. Ethical constraints have largely precluded human laboratory alcohol research in adolescence, and prospective studies have been rare. This paper provides an overview of developmental considerations in human laboratory alcohol research, with a focus on studies conducted with youth. RECENT FINDINGS Recent human laboratory studies from Europe and Canada have examined aspects of alcohol response during late adolescence, while recent survey studies from the United States have highlighted methods for circumventing alcohol administration in studies of adolescents. SUMMARY Across several decades of research, exceedingly few laboratory studies have examined developmental differences in alcohol responses or utilized prospective designs. Efforts to prioritize prospective research would further clarify the role of alcohol sensitivity traits as predictors or markers of AUD onset and progression.
Collapse
Affiliation(s)
- Christian S Hendershot
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Christina N Nona
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| |
Collapse
|
6
|
Rocha A, Hart N, Trujillo KA. Differences between adolescents and adults in the acute effects of PCP and ketamine and in sensitization following intermittent administration. Pharmacol Biochem Behav 2017; 157:24-34. [PMID: 28442368 DOI: 10.1016/j.pbb.2017.04.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/08/2023]
Abstract
Adolescence is a phase of development during which many physiological and behavioral changes occur, including increased novelty seeking and risk taking. In humans, this is reflected in experimentation with drugs. Research demonstrates that drug use that begins during adolescence is more likely to lead to addiction than drug use that begins later in life. Despite this, relatively little is known of the effects of drugs in adolescence, and differences in response between adolescents and adults. PCP and ketamine are popular club drugs, both possessing rewarding properties that could lead to escalating use. Drug sensitization (or reverse tolerance), which refers to an increase in an effect of a drug following repeated use, has been linked with the development of drug cravings that is a hallmark of addiction. The current work investigated the acute response and the development of sensitization to PCP and ketamine in adolescent and adult rats. Periadolescent Sprague-Dawley rats (30days or 38days of age), and young adults (60days of age) received PCP (6mg/kg IP) or ketamine (20mg/kg IP) once every three days, for a total of five drug injections. Adolescents and adults showed a stimulant response to the first injection of either drug, however the response was considerably greater in the youngest adolescents and lowest in the adults. With repeated administration, adults showed a robust escalation in activity that was indicative of the development of sensitization. Adolescents showed a flatter trajectory, with similar high levels of activity following an acute treatment and after five drug treatments. The results demonstrate important distinctions between adolescents and adults in the acute and repeated effects of PCP and ketamine.
Collapse
Affiliation(s)
- Angelica Rocha
- Office for Training Research, and Education in the Sciences, California State University San Marcos, CA 92096, USA
| | - Nigel Hart
- Office for Training Research, and Education in the Sciences, California State University San Marcos, CA 92096, USA
| | - Keith A Trujillo
- Office for Training Research, and Education in the Sciences, California State University San Marcos, CA 92096, USA; Department of Psychology, California State University San Marcos, CA 92096, USA.
| |
Collapse
|
7
|
Zhou L, Sun WL, Weierstall K, Minerly AC, Weiner J, Jenab S, Quinones-Jenab V. Sex differences in behavioral and PKA cascade responses to repeated cocaine administration. Psychopharmacology (Berl) 2016; 233:3527-36. [PMID: 27553823 DOI: 10.1007/s00213-016-4387-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 07/13/2016] [Indexed: 11/26/2022]
Abstract
Previous studies have shown sex different patterns in behavioral responses to cocaine. Here, we used between-subject experiment design to study whether sex differences exist in the development of behavioral sensitization and tolerance to repeated cocaine, as well as the role of protein kinase A (PKA) signaling cascade in this process. Ambulatory and rearing responses were recorded in male and female rats after 1 to 14 days of administration of saline or cocaine (15 mg/kg; ip). Correspondent PKA-associated signaling in the nucleus accumbens (NAc) and caudate-putamen (CPu) was measured at each time point. Our results showed that females exhibited higher cocaine-induced behavioral responses and developed behavioral sensitization and tolerance faster than males. Whereas females developed behavioral sensitization to cocaine after 2 days and tolerance after 14 days, male rats developed sensitization after 5 days. In addition, cocaine induced a sexual dimorphic pattern in the progression of neuronal adaptations on the PKA cascade signaling in region (NAc vs. CPu) and time (days of cocaine administration)-dependent manners. In general, more PKA signaling cascade changes were found in the NAc of males on day 5 and in the CPu of females with repeated cocaine injection. In addition, in females, behavioral activities positively correlated with FosB levels in the NAc and CPu and negatively correlated with Cdk5 and p35 in the CPu, while no correlation was observed in males. Our studies suggest that repeated cocaine administration induced different patterns of behavioral and molecular responses in the PKA cascade in male and female rats.
Collapse
Affiliation(s)
- Luyi Zhou
- Department of Biological Sciences, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biology PhD Program, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, 29208, USA
| | - Wei-Lun Sun
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, 29208, USA
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Karen Weierstall
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Ana Christina Minerly
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Jan Weiner
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Shirzad Jenab
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA
| | - Vanya Quinones-Jenab
- Department of Biology PhD Program, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA.
- Department of Psychology, Hunter College of the City University of New York, New York, NY, 10065, USA.
- Department of Biopsychology and Behavioral Neuroscience PhD Subprogram, Graduate School and University Center of the City University of New York, New York, NY, 10016, USA.
| |
Collapse
|
8
|
Carneiro de Oliveira PE, Leão RM, Bianchi PC, Marin MT, Planeta CDS, Cruz FC. Stress-Induced Locomotor Sensitization to Amphetamine in Adult, but not in Adolescent Rats, Is Associated with Increased Expression of ΔFosB in the Nucleus Accumbens. Front Behav Neurosci 2016; 10:173. [PMID: 27672362 PMCID: PMC5018519 DOI: 10.3389/fnbeh.2016.00173] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/30/2016] [Indexed: 12/18/2022] Open
Abstract
While clinical and pre-clinical evidence suggests that adolescence is a risk period for the development of addiction, the underlying neural mechanisms are largely unknown. Stress during adolescence has a huge influence on drug addiction. However, little is known about the mechanisms related to the interaction among stress, adolescence and addiction. Studies point to ΔFosB as a possible target for this phenomenon. In the present study, adolescent and adult rats (postnatal day 28 and 60, respectively) were restrained for 2 h once a day for 7 days. Three days after their last exposure to stress, the animals were challenged with saline or amphetamine (1.0 mg/kg i.p.) and amphetamine-induced locomotion was recorded. Immediately after the behavioral tests, rats were decapitated and the nucleus accumbens was dissected to measure ΔFosB protein levels. We found that repeated restraint stress increased amphetamine-induced locomotion in both the adult and adolescent rats. Furthermore, in adult rats, stress-induced locomotor sensitization was associated with increased expression of ΔFosB in the nucleus accumbens. Our data suggest that ΔFosB may be involved in some of the neuronal plasticity changes associated with stress induced-cross sensitization with amphetamine in adult rats.
Collapse
Affiliation(s)
- Paulo E Carneiro de Oliveira
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University-UNESP Araraquara, Brazil
| | - Rodrigo M Leão
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University-UNESP Araraquara, Brazil
| | - Paula C Bianchi
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University-UNESPAraraquara, Brazil; Joint Graduate Program in Physiological Sciences, UFSCar/UNESP, Faculdade de Odontologia de AraraquaraAraraquara, Brazil
| | - Marcelo T Marin
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University-UNESPAraraquara, Brazil; Joint Graduate Program in Physiological Sciences, UFSCar/UNESP, Faculdade de Odontologia de AraraquaraAraraquara, Brazil
| | - Cleopatra da Silva Planeta
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University-UNESPAraraquara, Brazil; Joint Graduate Program in Physiological Sciences, UFSCar/UNESP, Faculdade de Odontologia de AraraquaraAraraquara, Brazil
| | - Fábio C Cruz
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University-UNESP Araraquara, Brazil
| |
Collapse
|
9
|
Jones CG, Yang PB, Wilcox VT, Burau KD, Dafny N. Acute and chronic psychostimulant treatment modulates the diurnal rhythm activity pattern of WKY female adolescent rats. J Neural Transm (Vienna) 2014; 121:457-68. [PMID: 24482155 DOI: 10.1007/s00702-013-1141-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 12/12/2013] [Indexed: 11/28/2022]
Abstract
The psychostimulants considered the gold standard in the treatment of attention deficit hyperactivity disorder, one of the most common childhood disorders, are also finding their way into the hands of healthy young adults as brain augmentation to improve cognitive performance. The possible long-term effects of psychostimulant exposure in adolescence are considered controversial, and thus, the objective of this study was to investigate whether the chronic exposure to the psychostimulant amphetamine affects the behavioral diurnal rhythm activity patterns of female adolescent Wistar-Kyoto (WKY) rat. The hypothesis of this study is that change in diurnal rhythm activity pattern is an indicator for the long-term effect of the treatment. Twenty-four rats were divided into two groups, control (N = 12) and experimental (N = 12), and kept in a 12:12-h light/dark cycle in an open-field cage. After 5-7 days of acclimation, 11 days of consecutive non-stop behavioral recordings began. On experimental day 1 (ED1), all groups were given an injection of saline. On ED2 to ED7, the experimental group was injected with 0.6 mg/kg amphetamine followed by 3 days of washout from ED8 to ED10, and amphetamine re-challenge on ED11 similar to ED2. The locomotor movements were counted by the computerized animal activity monitoring system, and the cosinor statistical test analysis was used to fit a 24-h curve of the control recording to the activity pattern after treatment. The horizontal activity, total distance, number of stereotypy, vertical activity, and stereotypical movements were analyzed to find out whether the diurnal rhythm activity patterns were altered. Data obtained using these locomotor indices of diurnal rhythm activity pattern suggest that amphetamine treatment significantly modulates the locomotor diurnal rhythm activity pattern of female WKY adolescent rats.
Collapse
Affiliation(s)
- Cathleen G Jones
- Department of Neurobiology and Anatomy, The University of Texas-Medical School at Houston, P.O. Box 20708, Houston, TX, 77225, USA
| | | | | | | | | |
Collapse
|
10
|
Adult female rats' altered diurnal locomotor activity pattern following chronic methylphenidate treatment. J Neural Transm (Vienna) 2013; 120:1717-31. [PMID: 23893293 DOI: 10.1007/s00702-013-1063-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 06/25/2013] [Indexed: 12/25/2022]
Abstract
Methylphenidate (MPD) is one of the most prescribed pharmacological agents, which is also used for cognitive enhancement and recreational purposes. The objective of this study was to investigate the repetitive dose-response effects of MPD on circadian rhythm of locomotor activity pattern of female WKY rats. The hypothesis is that a change in the circadian activity pattern indicates a long-lasting effect of the drug. Four animal groups (saline control, 0.6, 2.5, and 10.0 mg/kg MPD dose groups) were housed in a sound-controlled room at 12:12 light/dark cycle. All received saline injections on experimental day 1 (ED 1). On EDs 2-7, the control group received saline injection; the other groups received 0.6, 2.5, or 10.0 mg/kg MPD, respectively. On ED 8-10, injections were withheld. On ED 11, each group received the same dose as EDs 2-7. Hourly histograms and cosine statistical analyses calculating the acrophase (ϕ), amplitude (A), and MESOR (M) were applied to assess the 24-h circadian activity pattern. The 0.6 and 2.5 mg/kg MPD groups exhibited significant (p < 0.05) change in their circadian activity pattern on ED 11. The 10.0 mg/kg MPD group exhibited tolerance on ED 11 and also a significant change in activity pattern on ED 8 compared to ED 1, consistent with withdrawal behavior (p < 0.007). In conclusion, chronic MPD administration alters circadian locomotor activity of adult female WKY rats and confirms that chronic MPD use elicits long-lasting effects.
Collapse
|
11
|
Zago A, Leão RM, Carneiro-de-Oliveira PE, Marin MT, Cruz FC, Planeta CS. Effects of simultaneous exposure to stress and nicotine on nicotine-induced locomotor activation in adolescent and adult rats. Braz J Med Biol Res 2011; 45:33-7. [PMID: 22086465 PMCID: PMC3854140 DOI: 10.1590/s0100-879x2011007500153] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 10/24/2011] [Indexed: 11/21/2022] Open
Abstract
Preclinical studies have shown that repeated stress experiences can result in an increase in the locomotor response to the subsequent administration of drugs of abuse, a phenomenon that has been termed behavioral cross-sensitization. Behavioral sensitization reflects neuroadaptive processes associated with drug addiction and drug-induced psychosis. Although cross-sensitization between stress- and drug-induced locomotor activity has been clearly demonstrated in adult rats, few studies have evaluated this phenomenon in adolescent rats. In the present study, we determined if the simultaneous exposure to stress and nicotine was capable of inducing behavioral sensitization to nicotine in adolescent and adult rats. To this end, adolescent (postnatal day (P) 28-37) and adult (P60-67) rats received nicotine (0.4 mg/kg, sc) or saline (0.9% NaCl, sc) and were immediately subjected to restraint stress for 2 h once a day for 7 days. The control group for stress was undisturbed following nicotine or saline injections. Three days after the last exposure to stress and nicotine, rats were challenged with a single dose of nicotine (0.4 mg/kg, sc) or saline and nicotine-induced locomotion was then recorded for 30 min. In adolescent rats, nicotine caused behavioral sensitization only in animals that were simultaneously exposed to stress, while in adult rats nicotine promoted sensitization independently of stress exposure. These findings demonstrate that adolescent rats are more vulnerable to the effects of stress on behavioral sensitization to nicotine than adult rats.
Collapse
Affiliation(s)
- A Zago
- Laboratório de Farmacologia, Universidade Estadual Paulista, Araraquara, SP, Brasil
| | | | | | | | | | | |
Collapse
|
12
|
Stress-induced cross-sensitization to amphetamine is related to changes in the dopaminergic system. J Neural Transm (Vienna) 2011; 119:415-24. [PMID: 22006016 DOI: 10.1007/s00702-011-0720-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 09/28/2011] [Indexed: 01/21/2023]
Abstract
Repeated stress engenders behavioral sensitization. The mesolimbic dopamine system is critically involved in drug-induced behavioral sensitization. In the present study we examined the differences between adolescent and adult rats in stress-induced behavioral sensitization to amphetamine and changes in dopamine (DA) and its metabolite levels in the mesolimbic system. Adolescent or adult rats were restrained for 2 h, once a day, for 7 days. Three days after the last exposure to stress, the animals were challenged with saline or amphetamine (1.0 mg/kg i.p.) and amphetamine-induced locomotion was recorded for 40 min. Immediately after the behavioral tests, rats were decapitated and the nucleus accumbens (NAcc), ventral tegmental area (VTA) and amygdala (AM) were removed to measure tissue levels of DA and its metabolites by HPLC. Exposure to repeated restraint stress promoted behavioral sensitization to amphetamine in both adult and adolescent rats. In adult rats, amphetamine administration increased DA levels in both the stress and control groups in the NAcc and VTA. In adolescent rats, amphetamine increased DA levels in the NAcc in rats exposed to stress. Furthermore, in the AM of adolescent rats in the control group, amphetamine increased the DA levels; however, amphetamine reduced this neurotransmitter in the rats that were exposed to stress. No alteration was observed in the dopamine metabolite levels. Therefore, stress promoted behavioral sensitization to amphetamine and this may be related to changes in DA levels in the mesolimbic system. These changes appear to be dependent on ontogeny.
Collapse
|
13
|
Abstract
Drug addiction is marked by continued drug-seeking behavior despite deleterious consequences and a heightened propensity to relapse not withstanding long, drug-free periods. The enduring nature of addiction has been hypothesized to arise from perturbations in intracellular signaling, gene expression, and brain circuitry induced by substance abuse. Ameliorating some of these aberrations should abate behavioral and neurochemical markers associated with an 'addiction phenotype'. This review summarizes data showing that protein expression and signaling through the nonreceptor activator of G-protein signaling 3 (AGS3) are altered by commonly abused substances in rat and in in-vitro addiction models. AGS3 structure and function are unrelated to the more broadly studied regulator of G-protein signaling family. Thus, the unique role of AGS3 is the focus of this review. Intriguingly, AGS3 protein changes persist into drug abstinence. Accordingly, studies probing the role of AGS3 in the neurochemistry of drug-seeking behavior and relapse are studied in detail. To illuminate this study, AGS3 structure, cellular localization, and function are covered so that an idealized AGS3-targeted pharmacotherapy can be proposed.
Collapse
Affiliation(s)
- Michael Scott Bowers
- Department of Psychiatry, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
| |
Collapse
|
14
|
Chandrasekar V, Dreyer JL. The brain-specific Neural Zinc Finger transcription factor 2b (NZF-2b/7ZFMyt1) causes suppression of cocaine-induced locomotor activity. Neurobiol Dis 2009; 37:86-98. [PMID: 19786102 DOI: 10.1016/j.nbd.2009.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 09/03/2009] [Accepted: 09/15/2009] [Indexed: 01/29/2023] Open
Abstract
Chronic cocaine induces high expression of the brain-specific Neural-Zinc-Finger transcription factor-2b (NZF-2b/7ZFMyt1), particularly in the mesolimbic dopaminergic pathway, resulting in a 11-fold increase in NZF-2b/7ZFMyt1 expression in the Nucleus Accumbens (NAc). Overexpression of this gene in the NAc with a NZF-2b/7ZFMyt1-expressing lentivirus resulted in >55% decrease in locomotor activity upon chronic cocaine administration, compared to control animals. In contrast knocking-down the gene in the NAc with lentiviruses expressing shRNAs against NZF-2b/7ZFMyt1 induced strong hyperlocomotor activity upon cocaine. Strong inhibition of BDNF is observed upon NZF-2b/7ZFMyt1 expression, concomitant with strong induction of transcription factors REST1 (RE silencing transcription factor-1) and NAC1, probably leading to regulation of gene expression by interaction with histone deacetylases. These changes lead to decreased responsiveness of the animal to the locomotor-activating effects of cocaine, indicating that NZF-2b/7ZFMyt1 expression plays an important role in phenotypic changes induced by the drug.
Collapse
Affiliation(s)
- Vijay Chandrasekar
- Division of Biochemistry, Department of Medicine, University of Fribourg, Rue du Musée 5, CH-1700 Fribourg, Switzerland
| | | |
Collapse
|
15
|
Mathews IZ, Waters P, McCormick CM. Changes in hyporesponsiveness to acute amphetamine and age differences in tyrosine hydroxylase immunoreactivity in the brain over adolescence in male and female rats. Dev Psychobiol 2009; 51:417-28. [DOI: 10.1002/dev.20381] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
16
|
O'Sullivan SS, Evans AH, Lees AJ. Dopamine dysregulation syndrome: an overview of its epidemiology, mechanisms and management. CNS Drugs 2009; 23:157-70. [PMID: 19173374 DOI: 10.2165/00023210-200923020-00005] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Dopamine dysregulation syndrome (DDS) is a relatively recently described iatrogenic disturbance that may complicate long-term symptomatic therapy of Parkinson's disease. Patients with DDS develop an addictive pattern of dopamine replacement therapy (DRT) use, administering doses in excess of those required to control their motor symptoms. The prevalence of DDS in patients attending specialist Parkinson's disease centres is 3-4%. Amongst the behavioural disturbances associated with DDS are punding, which is a complex stereotyped behaviour, and impulse control disorders (ICDs), such as pathological gambling, hypersexuality, compulsive shopping and compulsive eating. We review the risk factors and potential mechanisms for the development of DDS, including personality traits, potential genetic influences and Parkinson's disease-related cognitive deficits. Impulsive personality traits are prominent in patients developing DDS, and have been previously associated with the development of substance dependence. Candidate genes affecting the dopamine 'D(2)-like' receptor family have been associated with impulsive personality traits in addition to drug and nondrug addictions. Impaired decision making is implicated in addictive behaviours, and decision-making abilities can be influenced by dopaminergic medications. In Parkinson's disease, disruption of the reciprocal loops between the striatum and structures in the prefrontal cortex following dopamine depletion may predispose to DDS. The role of DRT in DDS is discussed, with particular reference to models of addiction, suggesting that compulsive drug use is due to progressive neuroadaptations in dopamine projections to the accumbens-related circuitry. Evidence for neuroadaptations and sensitization occurring in DDS include enhanced levodopa-induced ventral striatal dopamine release. Levodopa is still considered the most potent trigger for DDS in Parkinson's disease, but subcutaneous apomorphine and oral dopamine agonists may also be responsible. In the management of DDS, further research is needed to identify at-risk groups, thereby facilitating more effective early intervention. Therefore, an increased awareness of the syndrome amongst treating physicians is vital. Medication reduction strategies are employed, particularly with regard to avoiding rapidly acting 'booster' DRT formulations. Psychosocial treatments, including cognitive-behavioural therapy, have been beneficial in treating substance use disorders and ICDs in non-Parkinson's disease patients, but there are currently no published trials of psychological interventions in DDS. Further studies are also required to identify factors that can predict those patients with DDS or ICDs who will derive benefit from surgical interventions such as deep brain stimulation.
Collapse
Affiliation(s)
- Sean S O'Sullivan
- Reta Lila Weston Institute of Neurological Studies, Institute of Neurology, University College London, London, England
| | | | | |
Collapse
|
17
|
Rice OV, Grande AV, Dehktyar N, Bruneus M, Robinson JK, Gatley SJ. Long-term effects of irradiation with iron-56 particles on the nigrostriatal dopamine system. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2009; 48:215-225. [PMID: 19259693 DOI: 10.1007/s00411-009-0220-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 02/13/2009] [Indexed: 05/27/2023]
Abstract
Exposure to heavy ions during a Mars mission might damage the brain, thus compromising mission success and the quality of life of returning astronauts. Several workers have suggested that the dopamine system is particularly sensitive to heavy ion radiation, but direct evidence for this notion is lacking. We examined measures of brain dopamine viability at times up to 15 months after acute exposure of rats to (56)Fe (1.2-2.4 Gy). No effects were seen in brain sections stained for tyrosine hydroxylase, the classical marker for dopamine cells and nerve terminals. Locomotion stimulated by cocaine, which directly activates the dopamine system, was reduced at 6 months but not at 12 months. Furthermore, in a visually cued lever-pressing test, reaction times, which are prolonged by dopamine system damage, were identical in irradiated and control animals. However, learning times were increased by irradiation. Our data suggest that the midbrain dopamine system is not especially sensitive to damage by (56)Fe particles at doses much higher than would be associated with travel to and from Mars.
Collapse
Affiliation(s)
- Onarae V Rice
- Center for Translational Neuroimaging, Brookhaven National Laboratory, Upton, NY 11973, USA
| | | | | | | | | | | |
Collapse
|
18
|
Prolonged methylphenidate treatment alters the behavioral diurnal activity pattern of adult male Sprague-Dawley rats. Pharmacol Biochem Behav 2009; 92:93-9. [PMID: 19028517 DOI: 10.1016/j.pbb.2008.10.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2008] [Revised: 10/24/2008] [Accepted: 10/27/2008] [Indexed: 11/21/2022]
|
19
|
Wheeler RA, Twining RC, Jones JL, Slater JM, Grigson PS, Carelli RM. Behavioral and electrophysiological indices of negative affect predict cocaine self-administration. Neuron 2008; 57:774-85. [PMID: 18341996 DOI: 10.1016/j.neuron.2008.01.024] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 12/11/2007] [Accepted: 01/14/2008] [Indexed: 10/22/2022]
Abstract
The motivation to seek cocaine comes in part from a dysregulation of reward processing manifested in dysphoria, or affective withdrawal. Learning is a critical aspect of drug abuse; however, it remains unclear whether drug-associated cues can elicit the emotional withdrawal symptoms that promote cocaine use. Here we report that a cocaine-associated taste cue elicited a conditioned aversive state that was behaviorally and neurophysiologically quantifiable and predicted subsequent cocaine self-administration behavior. Specifically, brief intraoral infusions of a cocaine-predictive flavored saccharin solution elicited aversive orofacial responses that predicted early-session cocaine taking in rats. The expression of aversive taste reactivity also was associated with a shift in the predominant pattern of electrophysiological activity of nucleus accumbens (NAc) neurons from inhibitory to excitatory. The dynamic nature of this conditioned switch in affect and the neural code reveals a mechanism by which cues may exert control over drug self-administration.
Collapse
Affiliation(s)
- Robert A Wheeler
- Department of Psychology, University of North Carolina, Chapel Hill, NC 27599, USA
| | | | | | | | | | | |
Collapse
|
20
|
Mills K, Ansah T, Ali S, Mukherjee S, Shockley D. Augmented behavioral response and enhanced synaptosomal calcium transport induced by repeated cocaine administration are decreased by calcium channel blockers. Life Sci 2007; 81:600-8. [PMID: 17689567 PMCID: PMC2765982 DOI: 10.1016/j.lfs.2007.06.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Revised: 06/19/2007] [Accepted: 06/29/2007] [Indexed: 11/26/2022]
Abstract
Recent studies suggest that calcium influx via L-type calcium channels is necessary for psychostimulant-induced behavioral sensitization. In addition, chronic amphetamine upregulates subtype Cav1.2-containing L-type calcium channels. In the present studies, we assessed the effect of calcium channel blockers (CCBs) on cocaine-induced behavioral sensitization and determined whether the functional activity of L-type calcium channels is altered after repeated cocaine administration. Rats were administered daily intraperitoneal injections of either flunarizine (40 mg/kg), diltiazem (40 mg/kg) or cocaine (20 mg/kg) and the combination of the CCBs and cocaine for 30 days. Motor activities were monitored on Day 1, and every 6th day during the 30-day treatment period. Daily cocaine administration produced increased locomotor activity. Maximal augmentation of behavioral response to repeated cocaine administration was observed on Day 18. Flunarizine pretreatment abolished the augmented behavioral response to repeated cocaine administration while diltiazem was less effective. Measurement of tissue monoamine levels on Day 18 revealed cocaine-induced increases in DA and 5-HT in the nucleus accumbens. By contrast to behavioral response, diltiazem was more effective in attenuating increases in monoamine levels than flunarizine. Cocaine administration for 18 days produced increases in calcium uptake in synaptosomes prepared from the nucleus accumbens and frontal cortex. Increases in calcium uptake were abolished by flunarizine and diltiazem pretreatment. Taken together, the augmented cocaine-induced behavioral response on Day 18 may be due to increased calcium uptake in the nucleus accumbens leading to increased dopamine (DA) and serotonin (5-HT) release. Flunarizine and diltiazem attenuated the behavioral response by decreasing calcium uptake and decreasing neurochemical release.
Collapse
Affiliation(s)
- K. Mills
- Department of Pharmacology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, Tennessee 37208, USA
| | - T.A. Ansah
- Department of Pharmacology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, Tennessee 37208, USA
- Corresponding author: Department of Pharmacology, Meharry Medical College, 1005 D.B. Todd Blvd, Nashville, TN 37208, Tel: 615 327 6295, Fax: 615 327 6632, (T.A. Ansah)
| | - S.F. Ali
- Department of Pharmacology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, Tennessee 37208, USA
- Neurochemistry Laboratory, Division of Neurotoxicology, National Center for Toxicological Research/FDA, 3900 NCTR Drive, Jefferson, Arkansas 72079-9502, USA
| | - S. Mukherjee
- Department of Pharmacology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, Tennessee 37208, USA
| | - D.C. Shockley
- Department of Pharmacology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, Tennessee 37208, USA
| |
Collapse
|
21
|
Geary EH, Akins CK. Cocaine sensitization in male quail: temporal, conditioning, and dose-dependent characteristics. Physiol Behav 2007; 90:818-24. [PMID: 17316715 PMCID: PMC2095127 DOI: 10.1016/j.physbeh.2007.01.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Revised: 12/16/2006] [Accepted: 01/10/2007] [Indexed: 11/17/2022]
Abstract
Chronic cocaine administration typically results in increased locomotor activity, known as behavioral sensitization. Investigating the time course of locomotor activity across trials may provide a more detailed analysis of the temporal changes that might occur within sensitization. Prior research with rodents shows that the peak of locomotor activity shifts from acute to chronic drug administration. The purpose of the current experiment was to investigate acute versus chronic cocaine effects on locomotor activity in an avian species, Japanese quail, and to investigate whether this phenomenon is dose-dependent. Subjects received daily i.p. injections of saline or 5, 10, or 20 mg/kg cocaine for 20 days. Following each injection, birds were placed in standard locomotor activity chambers, and activity was recorded for 150 min. A cocaine challenge was given after a ten-day withdrawal period. Two retraining trials were given to re-establish cocaine responding prior to a saline challenge in the drug-paired environment. Results showed that repeated administration of the 10 mg/kg dose of cocaine enhanced activity across 120 min compared with acute administration. In contrast, repeated administration of the 20 mg/kg dose resulted in greater cocaine-induced activity for 60 min compared with acute administration. In addition, behavioral sensitization was shown to be dose-dependent and appeared to be due, at least in part, to conditioning.
Collapse
Affiliation(s)
- Emily H Geary
- Department of Psychology, University of Kentucky, Lexington, Kentucky 40506-0044, USA
| | | |
Collapse
|
22
|
Wedzony K, Markowicz-Kula K, Chocyk A, Fijał K, Maćkowiak M. The effect of ‘binge’ cocaine administration on the expression of cyclin-dependent kinase 5 and its activator p35 in various regions of rat brain. Brain Res 2005; 1063:195-200. [PMID: 16263094 DOI: 10.1016/j.brainres.2005.09.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 08/31/2005] [Accepted: 09/25/2005] [Indexed: 11/19/2022]
Abstract
The present study was aimed at determining whether the administration of cocaine in 'binge' pattern regimen that evoked tolerance to the locomotor stimulant effects of cocaine also influenced the expression of cyclin-dependent kinase 5 (Cdk5) and its activator p35 in the amygdala, medial prefrontal cortex, nucleus accumbens septi and caudate-putamen. Western blot techniques revealed that acute and repeated 'binge' cocaine decreased expression of the Cdk5 protein in the amygdala. In the medial prefrontal cortex, only exposure to repeated 'binge' cocaine decreased the content of the Cdk5 protein. 'Binge' cocaine administration also altered the expression of Cdk5 activator p35 protein. In the amygdala, only repeated 'binge' cocaine decreased the expression of p35, while in the medial prefrontal cortex, a decrease was observed after acute and repeated 'binge' cocaine exposure. In neither the nucleus accumbens septi nor the caudate-putamen acute or repeated 'binge' cocaine modified the expression of Cdk5 and p35. The above data indicate that in contrast to sensitizing doses of cocaine, a single and repeated binge of cocaine, which evoked tolerance to its locomotor stimulant effects, decreases expression of Cdk5 and p35 and possibly decreases the efficacy of neurotransmission or induces brain plastic changes regulated by Cdk5 and its activator p35.
Collapse
Affiliation(s)
- Krzysztof Wedzony
- Laboratory of Pharmacology and Brain Biostructure, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, PL 31-343 Kraków, Poland.
| | | | | | | | | |
Collapse
|
23
|
Hope BT, Crombag HS, Jedynak JP, Wise RA. Neuroadaptations of total levels of adenylate cyclase, protein kinase A, tyrosine hydroxylase, cdk5 and neurofilaments in the nucleus accumbens and ventral tegmental area do not correlate with expression of sensitized or tolerant locomotor responses to cocaine. J Neurochem 2005; 92:536-45. [PMID: 15659224 DOI: 10.1111/j.1471-4159.2004.02891.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neuroadaptations induced by high-dose cocaine treatment have been hypothesized to persist after the cessation of drug treatment and mediate the expression of sensitization and tolerance to cocaine. We looked for evidence of these neuroadaptations in rats receiving more modest behaviorally effective cocaine treatments. Rats were exposed to either a sensitizing regimen of seven once-daily injections of 15 mg/kg cocaine or a tolerance-producing regimen involving a continuous infusion of the same daily dose. We assessed enzyme activity levels of protein kinase A and adenylate cyclase, and protein levels of tyrosine hydroxylase, cdk5 and neurofilaments in the nucleus accumbens and ventral tegmental area. Only protein kinase A activity levels were altered by cocaine treatment, but this alteration persisted for only 7 days, whereas a sensitized locomotor response was still evident at 21 days. Although behavioral tolerance to cocaine was seen the day after the termination of treatment, none of the molecular measures was altered on this or any other day. Thus, although increased protein kinase A activity can temporarily modulate sensitized responses to cocaine, alterations in total levels of the molecules assessed in our study do not correlate with the expression of sensitized or tolerant locomotor responses to cocaine.
Collapse
Affiliation(s)
- B T Hope
- National Institute on Drug Abuse, National Institutes of Health/DHHS, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA.
| | | | | | | |
Collapse
|
24
|
Williams JM, Steketee JD. Time-dependent effects of repeated cocaine administration on dopamine transmission in the medial prefrontal cortex. Neuropharmacology 2005; 48:51-61. [PMID: 15617727 DOI: 10.1016/j.neuropharm.2004.09.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2004] [Revised: 08/30/2004] [Accepted: 09/15/2004] [Indexed: 11/28/2022]
Abstract
The medial prefrontal cortex (mPFC) has been implicated in the development of behavioral sensitization, which is the progressive enhancement of locomotor activity that occurs with repeated administration of psychostimulants. Previous data suggest that mPFC dopamine (DA) transmission may be attenuated in cocaine-sensitized animals, but the onset and duration of this effect have not been investigated. After recovery from stereotaxic surgeries, animals were given four daily injections of saline (1 ml/kg, i.p.) or cocaine (15 mg/kg, i.p.) and were subsequently challenged with saline or cocaine after 1, 7 or 30 d of withdrawal, on which days in vivo microdialysis of the mPFC was conducted simultaneously with monitoring of locomotor activity. Compared to acutely administered controls, the results in cocaine-pretreated animals were as follows: 1d of withdrawal was associated with a significant attenuation in cocaine-induced locomotion and mPFC DA overflow; after 7d, behavioral sensitization was accompanied by a significant attenuation in cocaine-induced elevations in mPFC DA levels; 30 d of withdrawal led to the expression of sensitized behaviors paralleled by an augmentation in cocaine-induced mPFC DA. These data suggest that repeated cocaine produces temporally distinct behavioral effects associated with alterations in mPFC DA responsiveness to cocaine that may be involved in the development of behavioral sensitization.
Collapse
Affiliation(s)
- Jason M Williams
- Department of Pharmacology, University of Tennessee Health Science Center, 874 Union Avenue, Memphis, TN 38163, USA
| | | |
Collapse
|
25
|
Abstract
Drugs of abuse are able to elicit compulsive drug-seeking behaviors upon repeated administration, which ultimately leads to the phenomenon of addiction. Evidence indicates that the susceptibility to develop addiction is influenced by sources of reinforcement, variable neuroadaptive mechanisms, and neurochemical changes that together lead to altered homeostasis of the brain reward system. Addiction is hypothesized to be a cycle of progressive dysregulation of the brain reward system that results in the compulsive use and loss of control over drug taking and the initiation of behaviors associated with drug seeking. The view that addiction represents a pathological state of reward provides an approach to identifying the factors that contribute to vulnerability, addiction, and relapse in genetic animal models.
Collapse
Affiliation(s)
- Aki Laakso
- Howard Hughes Medical Institute Laboratories, Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | | | | | | |
Collapse
|