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Briassoulis G, Keil MF, Naved B, Liu S, Starost MF, Nesterova M, Gokarn N, Batistatos A, Wu TJ, Stratakis CA. Studies of mice with cyclic AMP-dependent protein kinase (PKA) defects reveal the critical role of PKA's catalytic subunits in anxiety. Behav Brain Res 2016; 307:1-10. [PMID: 26992826 DOI: 10.1016/j.bbr.2016.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 02/23/2016] [Accepted: 03/01/2016] [Indexed: 12/21/2022]
Abstract
Cyclic adenosine mono-phosphate-dependent protein kinase (PKA) is critically involved in the regulation of behavioral responses. Previous studies showed that PKA's main regulatory subunit, R1α, is involved in anxiety-like behaviors. The purpose of this study was to determine how the catalytic subunit, Cα, might affect R1α's function and determine its effects on anxiety-related behaviors. The marble bury (MB) and elevated plus maze (EPM) tests were used to assess anxiety-like behavior and the hotplate test to assess nociception in wild type (WT) mouse, a Prkar1a heterozygote (Prkar1a(+/-)) mouse with haploinsufficiency for the regulatory subunit (R1α), a Prkaca heterozygote (Prkaca(+/-)) mouse with haploinsufficiency for the catalytic subunit (Cα), and a double heterozygote mouse (Prkar1a(+/-)/Prkaca(+/-)) with haploinsufficiency for both R1α and Cα. We then examined specific brain nuclei involved in anxiety. Results of MB test showed a genotype effect, with increased anxiety-like behavior in Prkar1a(+/-) and Prkar1a(+/-)/Prkaca(+/-) compared to WT mice. In the EPM, Prkar1a(+/-) spent significantly less time in the open arms, while Prkaca(+/-) and Prkar1a(+/-)/Prkaca(+/-) mice displayed less exploratory behavior compared to WT mice. The loss of one Prkar1a allele was associated with a significant increase in PKA activity in the basolateral (BLA) and central (CeA) amygdala and ventromedial hypothalamus (VMH) in both Prkar1a(+/-) and Prkar1a(+/-)/Prkaca(+/-) mice. Alterations of PKA activity induced by haploinsufficiency of its main regulatory or most important catalytic subunits result in anxiety-like behaviors. The BLA, CeA, and VMH are implicated in mediating these PKA effects in brain.
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Affiliation(s)
- George Briassoulis
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States; Department of Pediatric Intensive Care, University of Crete, Heraklion, Greece
| | - Margaret F Keil
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States.
| | - Bilal Naved
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Sophie Liu
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Matthew F Starost
- Division of Veterinary Resources, Office of Research Services (ORS), Office of the Director (OD), National Institutes of Health, Bethesda, MD 20892, United States
| | - Maria Nesterova
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Nirmal Gokarn
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Anna Batistatos
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - T John Wu
- Department of Obstetrics and Gynecology and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, United States
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Keil MF, Briassoulis G, Stratakis CA. The Role of Protein Kinase A in Anxiety Behaviors. Neuroendocrinology 2016; 103:625-39. [PMID: 26939049 DOI: 10.1159/000444880] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/19/2016] [Indexed: 11/19/2022]
Abstract
This review focuses on the genetic and other evidence supporting the notion that the cyclic AMP (cAMP) signaling pathway and its mediator, the protein kinase A (PKA) enzyme, which respond to environmental stressors and regulate stress responses, are central to the pathogenesis of disorders related to anxiety. We describe the PKA pathway and review in vitro animal studies (mouse) and other evidence that support the importance of PKA in regulating behaviors that lead to anxiety. Since cAMP signaling and PKA have been pharmacologically exploited since the 1940s (even before the identification of cAMP as a second messenger with PKA as its mediator) for a number of disorders from asthma to cardiovascular diseases, there is ample opportunity to develop therapies using this new knowledge about cAMP, PKA, and anxiety disorders.
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Affiliation(s)
- Margaret F Keil
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Md., USA
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Rodgers RJ. No man is an island. A personal tribute to Bob Blanchard and ethoexperimental approaches to the study of behaviour. Physiol Behav 2015; 146:2-6. [PMID: 25497885 DOI: 10.1016/j.physbeh.2014.12.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022]
Abstract
I first met Bob Blanchard at an international conference in Paris some 40 years ago. We collaborated intensively during the late 1980s/early 1990s on the ethopharmacology of antipredator defence in wild and laboratory rats, and remained good friends until his untimely passing in November 2013. Bob will undoubtedly be remembered as one of the most influential behavioural neuroscientists of the 20th century and, with Caroline, the most eloquent advocate of ethoexperimental approaches to the study of behaviour. In this brief trip down memory lane, I describe when and where Bob and I first met and how, over a lengthy period, he directly and indirectly helped shape my own research career. His profound influence in this regard is illustrated by reference to not only our collaborative research on antipredator behaviour but also my other work on the ethopharmacology of agonistic behaviour, social conflict analgesia, anxiety, and appetite. The element common to all of this work has been ethoexperimental analysis and, for teaching me the true value of this approach, I shall always remain indebted to the big man. Literally and figuratively, Bob was most certainly larger than life.
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Differential behavioral responses of zebrafish larvae to yohimbine treatment. Psychopharmacology (Berl) 2015; 232:197-208. [PMID: 24958231 DOI: 10.1007/s00213-014-3656-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 06/02/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Yohimbine demonstrated both anxiogenic and anxiolytic properties under different conditions in rodents. Few studies were conducted on zebrafish, a newly emerged vertebrate model organism. Zebrafish larvae are particularly suitable for high-throughput screening of drug effects. OBJECTIVES The aim of this study was to elucidate the effect of yohimbine on the anxiety-related behaviors of zebrafish larvae. METHODS AB strain zebrafish larvae at both 5 and 7 days postfertilization (dpf) were treated with different concentrations of yohimbine. General locomotor activities and thigmotaxis behavior were analyzed under continuous illumination, which represented normal condition, or under alternating light-dark challenges, which represented stressful environment. RESULTS Under continuous illumination, the 5-dpf larvae demonstrated increased swimming distances at low yohimbine concentrations, whereas the 7-dpf larvae demonstrated progressively decreased swimming distances with increases in yohimbine concentration. Low concentrations of yohimbine reduced thigmotaxis of the larvae, while high concentrations of yohimbine increased it. During the dark period of the light-dark challenge phase, low concentrations of yohimbine increased swimming distances of the larvae at both 5 and 7 dpf, while high concentrations of yohimbine decreased it. Yohimbine induced increased thigmotaxis in both 5- and 7-dpf larvae during the dark period. CONCLUSIONS Under normal condition (lights on), low doses of yohimbine were anxiolytic in both the 5- and 7-dpf larvae, whereas high doses of yohimbine were anxiogenic only in the 7-dpf larvae. Under mildly stressful condition (lights off), yohimbine treatment demonstrated dose-dependent effects to potentiate anxiety-related behaviors in both the 5- and 7-dpf larvae, although the significant dose varied with age.
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Wrenn CC, Heitzer AM, Roth AK, Nawrocki L, Valdovinos MG. Effects of clonidine and methylphenidate on motor activity in Fmr1 knockout mice. Neurosci Lett 2014; 585:109-13. [PMID: 25433180 DOI: 10.1016/j.neulet.2014.11.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 11/04/2014] [Accepted: 11/24/2014] [Indexed: 01/27/2023]
Abstract
Fragile X syndrome (FXS), a disorder caused by a mutation in the FMR1 gene, is often associated with Attention Deficit Hyperactivity Disorder (ADHD). Common treatments for the hyperactivity often seen in ADHD involve the use of stimulants and α2-adrenergic agonists. The Fmr1 knockout (KO) mouse has been found to be a valid model for FXS both biologically and behaviorally. Of particular interest to our research, the Fmr1 KO mouse has been demonstrated to show increased locomotion in comparison to wild type (WT) littermates. In the present study, we assessed the effects of clonidine (0.05 mg/kg) and methylphenidate (5 mg/kg) on motor activity in Fmr1 KO mice and their WT littermates in the open field test. Results showed that methylphenidate increased motor activity in both genotypes. Clonidine decreased motor activity in both genotypes, but the effect was delayed in the Fmr1 KO mice.
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Affiliation(s)
- Craige C Wrenn
- College of Pharmacy & Health Sciences, Drake University, 2507 University Avenue, Des Moines, IA 50311, USA
| | - Andrew M Heitzer
- Department of Psychology, Drake University, 2507 University Avenue, Des Moines, IA 50311, USA
| | - Alexandra K Roth
- Department of Psychology, Drake University, 2507 University Avenue, Des Moines, IA 50311, USA
| | - Lauren Nawrocki
- Neuroscience Program, Drake University, 2507 University Avenue, Des Moines, IA 50311, USA
| | - Maria G Valdovinos
- Department of Psychology, Drake University, 2507 University Avenue, Des Moines, IA 50311, USA.
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Sorregotti T, Mendes-Gomes J, Rico JL, Rodgers RJ, Nunes-de-Souza RL. Ethopharmacological analysis of the open elevated plus-maze in mice. Behav Brain Res 2013; 246:76-85. [DOI: 10.1016/j.bbr.2013.02.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/20/2013] [Accepted: 02/24/2013] [Indexed: 10/27/2022]
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Campos KFC, Amaral VCS, Rico JL, Miguel TT, Nunes-de-Souza RL. Ethopharmacological evaluation of the rat exposure test: a prey-predator interaction test. Behav Brain Res 2012. [PMID: 23195112 DOI: 10.1016/j.bbr.2012.11.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The rat exposure test (RET) is a prey (mouse)-predator (rat) situation that activates brain defensive areas and elicits hormonal and defensive behavior in the mouse. Here, we investigated possible correlations between the spatiotemporal [time spent in protected (home chamber and tunnel) and unprotected (surface) compartments and frequency of entries into the three compartments] and ethological [e.g., duration of protected and unprotected stretched-attend postures (SAP), duration of contact with the rat's compartment] measures (Experiment 1). Secondly, we investigated the effects of systemic treatment with pro- or anti-aversive drugs on the behavior that emerged from the factor analysis (Experiment 2). The effects of chronic (21 days) imipramine and fluoxetine on defensive behavior were also investigated (Experiment 3). Exp. 1 revealed that the time in the protected compartment, protected SAP and rat contacts loaded on factor 1 (defensive behavior), while the total entries and unprotected SAP loaded on factor 2 (locomotor activity). Exp. 2 showed that alprazolam (but not diazepam) selectively changed the defensive factor. Caffeine produced a mild proaversive-like effect, whereas yohimbine only decreased locomotor activity (total entries). Fluoxetine (but not imipramine) produced a weak proaversive-like effect. 5-HT(1A)/5-HT(2) receptor ligands did not change any behavioral measure. In Exp. 3, chronic fluoxetine (but not imipramine) attenuated the defensive behavior factor without changing locomotion. Given that the defensive factor was sensitive to drugs known to attenuate (alprazolam and chronic fluoxetine) and induce (caffeine) panic attack, we suggest the RET as a useful test to assess the effects of panicolytic and panicogenic drugs.
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Affiliation(s)
- Kelciane Ferreira Caetano Campos
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Universidade Estadual Paulista, UNESP, Araraquara, SP 14801-902, Brazil
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Keil MF, Briassoulis G, Gokarn N, Nesterova M, Wu T, Stratakis CA. Anxiety phenotype in mice that overexpress protein kinase A. Psychoneuroendocrinology 2012; 37:836-43. [PMID: 22024111 PMCID: PMC3320692 DOI: 10.1016/j.psyneuen.2011.09.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 09/07/2011] [Accepted: 09/29/2011] [Indexed: 01/13/2023]
Abstract
The role of cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signaling in the molecular pathways involved in fear and memory is well established. Prior studies in our lab reported that transgenic mice with an inactivating mutation in Prkar1a gene (codes for the 1-alpha regulatory subunit (R1α) of PKA) exhibited behavioral abnormalities including anxiety and depression. In the present study, we examined the role of altered PKA signaling on anxiety-like behaviors in Prkar1a(+/-) mice compared to wild-type (WT) littermates. The elevated plus maze (EPM) and marble bury (MB) tests were used to assess anxiety-like behavior. The hotplate test was performed to evaluate analgesia. We further examined the impact of the Prkar1a inactivating mutation on PKA activity in specific nuclei of the brain associated with anxiety-like behavior. Results for the MB test showed a genotype effect, with increased anxiety-like behavior in Prkar1a(+/-) mice, compared to WT littermates (p<0.05). MANOVA analysis showed a significant genotype difference in anxiety-like behavior in the EPM between WT and Prkar1a(+/-) mice on combined dependent variables (open arm time and open to total time ratio; p<0.05). Results of hotplate testing showed no genotype effect however; the expected sex difference was noted. Analysis of PKA activity showed the loss of one Prkar1a allele led to an increase in basal and cAMP-stimulated kinase activity in both the basolateral and central amygdala. These results suggest that the alteration in PKA signaling in Prkar1a(+/-) mice is not a ubiquitous effect; and supports the importance of cAMP/PKA pathway in neurobiological processes involved in anxiety and fear sensitization.
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Affiliation(s)
- Margaret F. Keil
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892
- Graduate School of Nursing, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - George Briassoulis
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892
| | - Nirmal Gokarn
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892
| | - Maria Nesterova
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892
| | - T.John Wu
- Department of Obstetrics and Gynecology and Program in Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Constantine A. Stratakis
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD 20892
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Laarakker MC, Raai JRV, van Lith HA, Ohl F. The role of the alpha 2A-adrenoceptor in mouse stress-coping behaviour. Psychoneuroendocrinology 2010; 35:490-502. [PMID: 19766405 DOI: 10.1016/j.psyneuen.2009.08.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 08/18/2009] [Accepted: 08/21/2009] [Indexed: 11/30/2022]
Abstract
Acute stress is known to impair memory functions in both men and laboratory rodents. In human the alpha 2A-adrenoceptor system is known to play a critical role in regulating acute neuropsychological stress responses and, ultimately, stress-coping behaviour. In search for neurobiological and central nervous mechanisms behind these behaviours we investigated if the alpha 2A-adrenoceptor is involved in these mechanisms in mice. Phenotypical differences between the A/J and C57BL/6J (B6) mouse inbred strains were evaluated in previous studies. These data showed significant strain differences in various motivational systems (anxiety, exploration, locomotion, memory etc.). From the literature it is known that chromosome 19 contains the gene for the adrenergic alpha 2A receptor that is thought to be involved in emotional behaviours, among others anxiety-related avoidance behaviour and arousal. We investigated if this pathway could possibly be involved in avoidance/arousal susceptibility by applying an agonist (dexmedetomidine) and an antagonist (atipamezole) of the alpha 2A-adrenoceptor to male mice from a consomic strain (C57BL/6J-Chr 19(A)/NaJ, abbreviated to CSS19=anxious), and the corresponding donor (A/J=anxious) and host (B6=non-anxious) strains. The mice were tested in the modified hole board (mHB) test which allows for the assessment of a variety of behavioural patterns by use of only one test. In addition, a forced swimming test (FST) was conducted to test for stress-coping behaviour. Results of the behavioural testing in the mHB-test showed significant strains differences and strain-specific treatment effects for parameters describing anxiety-related endophenotypes. The FST revealed effects of dexmedetomidine and atipamezole on stress-coping behaviour. In conclusion, the involvement of the alpha 2A-adrenoceptor, located on mouse chromosome 19, on anxiety-related behaviour remains unclear and will possibly not play a main role in the development of anxiety-related behaviour in mice. However, we could show involvement of this receptor in stress-coping behaviour in mice.
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Affiliation(s)
- Marijke C Laarakker
- Department of Animals in Science & Society, Division of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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Holmes A, Quirk GJ. Pharmacological facilitation of fear extinction and the search for adjunct treatments for anxiety disorders--the case of yohimbine. Trends Pharmacol Sci 2009; 31:2-7. [PMID: 20036429 DOI: 10.1016/j.tips.2009.10.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 10/02/2009] [Accepted: 10/05/2009] [Indexed: 11/15/2022]
Abstract
There is current interest in identifying drugs that facilitate fear extinction, as this form of learning is the basis of certain cognitive therapies for anxiety disorders. Following an initial report several years ago that the alpha2-adrenoreceptor antagonist yohimbine facilitated extinction in mice, more recent studies have shown mixed effects or even impairment. It has become clear that the effect of yohimbine on extinction depends on a number of factors, including genetic background, contextual variables and the presence of competing behaviors. To what extent theses effects of yohimbine are mediated through the alpha2-adrenoreceptor, as opposed to other sites of action, is also uncertain. More work is needed before this drug can be approved as a pharmacological adjunct for extinction-based therapies. More generally, the case of yohimbine may serve as a model for the development of other extinction facilitators.
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Affiliation(s)
- Andrew Holmes
- Section on Behavioral Science and Genetics, Laboratory for Integrative Neuroscience, National Institute on Alcoholism and Alcohol Abuse, NIH, Bethesda, MD 20852, USA
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Votava M, Hess L, Slíva J, Krsiak M, Agová V. Dexmedetomidine selectively suppresses dominant behaviour in aggressive and sociable mice. Eur J Pharmacol 2005; 523:79-85. [PMID: 16226250 DOI: 10.1016/j.ejphar.2005.08.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 08/10/2005] [Indexed: 11/21/2022]
Abstract
Dexmedetomidine is a highly specific alpha2-adrenoreceptor agonist, which is now clinically used to induce sedation in patients in the intensive care units. Behavioural effects of dexmedetomidine have been little studied so far. The drug was reported to reduce behaviour such as locomotion or measures of anxiety or aggression in animals. The aim of the present study was to ascertain whether dexmedetomidine inhibits behaviour uniformly or with respect to particular stimuli or situations. Therefore, behavioural effects of dexmedetomidine were studied in the social conflict test in male mice (after three weeks of individual housing), which provides a wide spectrum of behavioural activities in two types of animals (aggressive and sociable mice) as well as in the activity cage. Dexmedetomidine (5-40 microg/kg i.p.) decreased locomotion in the activity cage and this effect was fully antagonized by atipamezole, a selective alpha2-adrenereceptor antagonist. However, dexmedetomidine did not reduce locomotion during social conflict. The only significant effects during social conflict were a selective and dose-dependent antiaggressive effect in aggressive mice and a selective reduction of social investigation ('sociability') in sociable mice. Thus, dexmedetomidine appears to inhibit predominantly dominant behaviour evoked by biologically important stimuli. The ability of dexmedetomidine to reduce aggression might be utilized for treatment of aggressive states. Sedation caused by dexmedetomidine can be easily disrupted and thus the drug may have an advantage over benzodiazepines or neuroleptics, which are used in this indication.
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Affiliation(s)
- Martin Votava
- Pharmacology Department, Charles University, 3rd Faculty of Medicine, Ruská 87, 100 00, Prague 10, Czech Republic.
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Massé F, Hascoët M, Bourin M. α2-Adrenergic agonists antagonise the anxiolytic-like effect of antidepressants in the four-plate test in mice. Behav Brain Res 2005; 164:17-28. [PMID: 16081166 DOI: 10.1016/j.bbr.2005.05.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Revised: 05/03/2005] [Accepted: 05/04/2005] [Indexed: 11/28/2022]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) and serotonin/noradrenaline reuptake inhibitors (SNRIs) has been reported to be efficient in anxiety disorders. Some animal models have demonstrated an anxiolytic-like effect following acute administration, however, it is not yet known how noradrenergic receptors are implicated in the therapeutic effects of antidepressants (ADs) in anxiety. The effects of two alpha(2)-adrenoceptor agonists (clonidine, guanabenz) on anxiolytic-like effect of two SSRIs (paroxetine and citalopram) and two SNRIs (venlafaxine and milnacipran) were evaluated in the four-plate test (FPT) in mice. Paroxetine (4 mg/kg), citalopram (8 mg/kg), venlafaxine (8 mg/kg), and milnacipran (8 mg/kg) administered intraperitoneally (i.p.) increased the number of punishments accepted by mice in the FPT. Clonidine (0.0039-0.5 mg/kg) and guanabenz (0.03-0.5mg/kg) had no effect on the number of punishments accepted by mice. Clonidine (0.03 and 0.06 mg/kg) and guanabenz (0.125 and 0.5 mg/kg) (i.p. -45 min) reversed the anti-punishment effect of paroxetine, citalopram, venlafaxine and milnacipran (i.p. -30 min). But if the antidepressants are administered 45 min before the test and alpha(2)-adrenoceptor agonists 30 min before the test, alpha(2)-adrenoceptor agonists failed to alter the anti-punishment effect of antidepressants. The results of this present study indicate that alpha(2)-adrenoceptor agonists antagonise the anxiolytic-like effect of antidepressants in mice when they are administered 15 min before the administration of antidepressant suggesting a close inter-regulation between noradrenergic and serotoninergic system in the mechanism of SSRIs and SNRIs in anxiety-like behaviour.
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Affiliation(s)
- Fabienne Massé
- Neurobiology of Anxiety and Depression, Faculty of Medicine, Nantes, France
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Shishkina GT, Kalinina TS, Dygalo NN. Attenuation of alpha2A-adrenergic receptor expression in neonatal rat brain by RNA interference or antisense oligonucleotide reduced anxiety in adulthood. Neuroscience 2005; 129:521-8. [PMID: 15541874 DOI: 10.1016/j.neuroscience.2004.08.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2004] [Indexed: 11/24/2022]
Abstract
Brain alpha2-adrenergic receptors (alpha2-ARs) have been implicated in the regulation of anxiety, which is associated with stress. Environmental treatments during neonatal development could modulate the level of brain alpha2-AR expression and alter anxiety in adults, suggesting possible involvement of these receptors in early-life programming of anxiety state. The present study was undertaken to determine whether the reduction of the expression of A subtype of these receptors most abundant in the neonatal brain affects anxiety-related behavior in adulthood. We attenuated the expression of alpha2A-ARs during neonatal life by two different sequence specific approaches, antisense technology and RNA interference. Treatment of rats with the antisense oligodeoxynucleotide or short interfering RNA (siRNA) against alpha2A-ARs on the days 2-4 of their life, produced a marked acute decrease in the levels of both alpha2A-AR mRNA and [3H]RX821002 binding sites in the brainstem into which drugs were injected. The decrease of alpha2A-AR expression in the neonatal brainstem influenced the development of this receptor system in the brain regions as evidenced by the increased number of [3H]RX821002 binding sites in the hypothalamus of adult animals with both neonatal alpha2A-AR knockdown treatments; also in the frontal cortex of antisense-treated, and in the hippocampus of siRNA-treated adult rats. These adult animals also demonstrated a decreased anxiety in the elevated plus-maze as evidenced by an increased number of the open arm entries, greater proportion of time spent in the open arms, and more than a two-fold increase in the number of exploratory head dips. The results provide the first evidence that the reduction in the brain expression of a gene encoding for alpha2A-AR during neonatal life led to the long-term neurochemical and behavioral alterations. The data suggests that alterations in the expression of the receptor-specific gene during critical periods of brain development may be involved in early-life programming of anxiety-related behavior.
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MESH Headings
- Adrenergic alpha-Antagonists/pharmacokinetics
- Analysis of Variance
- Animals
- Animals, Genetically Modified
- Animals, Newborn
- Anxiety/drug therapy
- Behavior, Animal
- Blotting, Southern/methods
- Brain Stem/drug effects
- Brain Stem/growth & development
- Gene Expression Regulation, Developmental/drug effects
- Idazoxan/analogs & derivatives
- Idazoxan/pharmacokinetics
- Maze Learning/drug effects
- Norepinephrine/metabolism
- Oligodeoxyribonucleotides, Antisense/administration & dosage
- Protein Binding/drug effects
- RNA, Messenger/metabolism
- RNA, Small Interfering/administration & dosage
- Radioligand Assay
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-2/genetics
- Receptors, Adrenergic, alpha-2/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Tritium/pharmacokinetics
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Affiliation(s)
- G T Shishkina
- Institute of Cytology and Genetics, Lavrentjev Av. 10, Novosibirsk 630090, Russia
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14
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Risbrough VB, Geyer MA. Anxiogenic treatments do not increase fear-potentiated startle in mice. Biol Psychiatry 2005; 57:33-43. [PMID: 15607298 DOI: 10.1016/j.biopsych.2004.10.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 08/09/2004] [Accepted: 10/20/2004] [Indexed: 11/23/2022]
Abstract
BACKGROUND In rodents, the fear-potentiated startle paradigm (FPS; exaggerated startle as a measure of the conditioned fear response to cues associated with footshock) has demonstrated predictive validity for anxiolytic drugs. The predictive validity of the model for anxiogenic drugs, however, remains unclear. Therefore, we evaluated the bi-directionality of the FPS model for anxiety-modulating compounds in mice. METHODS The clinical anxiogenics FG-7142 (1-20 mg/kg), yohimbine (.1-10 mg/kg), and m-Chlorophenylpiperazine (mCPP; .3-3 mg/kg), and the putative anxiogenics atipamezole (.3-3 mg/kg) and corticotropin-releasing factor (h/r-CRF; .03-1 microg) were tested in DBA/1J mice trained for FPS. RESULTS Contrary to predictions, FG-7142 (10 and 20 mg/kg) and yohimbine (10 mg/kg) reduced FPS in mice without affecting baseline startle. Atipamezole (3 mg/kg), mCPP (3 mg/kg), and h/r-CRF (.3, 1 microg) did not affect FPS, but increased startle independently from the presence of the cue. FG-7142 and h/r-CRF had similar effects in 129SvEv mice. CONCLUSIONS Murine FPS is not bi-directionally predictive for anxiety-modulating compounds, although murine baseline startle may have some utility as a bi-directional model of anxiety. These data corroborate the recent hypothesis that systems mediating FPS are independent from systems mediating increased startle from unconditioned and putatively anxiogenic stimuli.
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Affiliation(s)
- Victoria B Risbrough
- Departments of Psychiatry and Neurosciences, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0804, USA
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15
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Lepicard EM, Venault P, Negroni J, Perez-Diaz F, Joubert C, Nosten-Bertrand M, Berthoz A, Chapouthier G. Posture and balance responses to a sensory challenge are related to anxiety in mice. Psychiatry Res 2003; 118:273-84. [PMID: 12834821 DOI: 10.1016/s0165-1781(03)00069-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Anxiety disorders and balance disorders share common clinical features related to perception such as spatial disorientation or dizziness. The search for the mechanism underlying this core of symptoms led us to investigate impairments in multisensory integration. In mice, the 'rotating beam test' allows analysis of changes in balance control and posture in response to a multisensory challenge. We used the BALB/c and C57BL/6 inbred strains of mice, known for their contrasted anxiety-related behavior. The level of anxiety was also manipulated using anxiolytic and anxiogenic pharmacological compounds. Despite equal sensori-motor abilities, anxious mice were more prone to fall off the rotating beam and showed more imbalance than non-anxious mice. Striking inter-strain differences in posture were also observed. Diazepam and beta-CCM reversed these strain-specific responses in opposite directions. We demonstrated that balance and postural strategies developed in response to a multisensory challenge vary as a function of the level of anxiety in mice.
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Affiliation(s)
- Eve M Lepicard
- CNRS UMR 7593 'Vulnérabilité, Adaptation et Psychopathologie', CHU Pitié-Salpêtrière, 91, bd de l'Hôpital, 75013 Paris, France.
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16
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Abstract
Fear is an adaptive component of the acute "stress" response to potentially-dangerous (external and internal) stimuli which threaten to perturb homeostasis. However, when disproportional in intensity, chronic and/or irreversible, or not associated with any genuine risk, it may be symptomatic of a debilitating anxious state: for example, social phobia, panic attacks or generalized anxiety disorder. In view of the importance of guaranteeing an appropriate emotional response to aversive events, it is not surprising that a diversity of mechanisms are involved in the induction and inhibition of anxious states. Apart from conventional neurotransmitters, such as monoamines, gamma-amino-butyric acid (GABA) and glutamate, many other modulators have been implicated, including: adenosine, cannabinoids, numerous neuropeptides, hormones, neurotrophins, cytokines and several cellular mediators. Accordingly, though benzodiazepines (which reinforce transmission at GABA(A) receptors), serotonin (5-HT)(1A) receptor agonists and 5-HT reuptake inhibitors are currently the principle drugs employed in the management of anxiety disorders, there is considerable scope for the development of alternative therapies. In addition to cellular, anatomical and neurochemical strategies, behavioral models are indispensable for the characterization of anxious states and their modulation. Amongst diverse paradigms, conflict procedures--in which subjects experience opposing impulses of desire and fear--are of especial conceptual and therapeutic pertinence. For example, in the Vogel Conflict Test (VCT), the ability of drugs to release punishment-suppressed drinking behavior is evaluated. In reviewing the neurobiology of anxious states, the present article focuses in particular upon: the multifarious and complex roles of individual modulators, often as a function of the specific receptor type and neuronal substrate involved in their actions; novel targets for the management of anxiety disorders; the influence of neurotransmitters and other agents upon performance in the VCT; data acquired from complementary pharmacological and genetic strategies and, finally, several open questions likely to orientate future experimental- and clinical-research. In view of the recent proliferation of mechanisms implicated in the pathogenesis, modulation and, potentially, treatment of anxiety disorders, this is an opportune moment to survey their functional and pathophysiological significance, and to assess their influence upon performance in the VCT and other models of potential anxiolytic properties.
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Affiliation(s)
- Mark J Millan
- Psychopharmacology Department, Centre de Rescherches de Croissy, Institut de Recherches (IDR) Servier, 125 Chemin de Ronde, 78290 Croissy-sur-Seine, Paris, France.
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17
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Millan MJ, Brocco M. The Vogel conflict test: procedural aspects, gamma-aminobutyric acid, glutamate and monoamines. Eur J Pharmacol 2003; 463:67-96. [PMID: 12600703 DOI: 10.1016/s0014-2999(03)01275-5] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A multitude of mechanisms are involved in the control of emotion and in the response to stress. These incorporate mediators/targets as diverse as gamma-aminobutyric acid (GABA), excitatory amino acids, monoamines, hormones, neurotrophins and various neuropeptides. Behavioural models are indispensable for characterization of the neuronal substrates underlying their implication in the etiology of anxiety, and of their potential therapeutic pertinence to its management. Of considerable significance in this regard are conflict paradigms in which the influence of drugs upon conditioned (trained) behaviours is examined. For example, the Vogel conflict test, which was introduced some 30 years ago, measures the ability of drugs to release the drinking behaviour of water-deprived rats exposed to a mild aversive stimulus ("punishment"). This model, of which numerous procedural variants are discussed herein, has been widely used in the evaluation of potential anxiolytic agents. In particular, it has been exploited in the characterization of drugs interacting with GABAergic, glutamatergic and monoaminergic networks, the actions of which in the Vogel conflict test are summarized in this article. More recently, the effects of drugs acting at neuropeptide receptors have been examined with this model. It is concluded that the Vogel conflict test is of considerable utility for rapid exploration of the actions of anxiolytic (and anxiogenic) drugs. Indeed, in view of its clinical relevance, broader exploitation of the Vogel conflict test in the identification of novel classes of anxiolytic agents, and in the determination of their mechanisms of action, would prove instructive.
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Affiliation(s)
- Mark J Millan
- Psychopharmacology Department, Institut de Recherches Servier, Centre de Recherches de Croissy, 125 Chemin de Ronde, 78290 Croissy/Seine, Paris, France.
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18
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Rodgers RJ, Davies B, Shore R. Absence of anxiolytic response to chlordiazepoxide in two common background strains exposed to the elevated plus-maze: importance and implications of behavioural baseline. GENES, BRAIN, AND BEHAVIOR 2002; 1:242-51. [PMID: 12882369 DOI: 10.1034/j.1601-183x.2002.10406.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Although genetic background is acknowledged as a potentially important determinant of mutant phenotypes, publications on genetically modified mice far outnumber those on progenitor strains. We have recently reported major differences in basal anxiety levels (elevated plus-maze & light/dark exploration) among three strains (C57BL/6JOlaHsd, 129/SvEv and 129S2/SvHsd) employed as progenitor stock in European laboratories (Rodgers et al. in press). Furthermore, the phenotypes of these inbred strains differed significantly from that of an outbred strain (Swiss-Webster) commonly used in behavioural pharmacology. In view of these findings, the present study assessed possible differences in the anxiolytic efficacy of chlordiazepoxide (0, 7.5 & 15.0 mg/kg, IP) in three of these strains (Swiss-Webster (SW), C57BL/6JOIaHsd (C57) & 129S2/SvHsd (129)). Experimentally naive mice were exposed to the elevated plus-maze, sessions were videotaped and behaviour analysed using ethological software. The performance of control subjects confirmed significant strain differences in basal levels of activity (SW > C57 > 129) and anxiety-related behaviours (129 = SW > C57), with hypolocomotion dominating the 129 profile. SW mice displayed an anxioselective response to both doses of chlordiazepoxide (CDP), with significant reductions in open arm avoidance and risk assessment observed in the absence of any change in general activity. In direct contrast, the lower dose of CDP (7.5 mg/kg) was without effect in either inbred strain, whereas treatment with 15.0 mg/kg induced a profile indicative of muscle relaxation/mild sedation in C57 mice and virtually abolished all behavioural activity in 129 mice. Although the absence of an anxiolytic response to CDP in C57 mice may be attributed to their low basal anxiety levels, the profile of 129 mice strongly suggests an abnormality in benzodiazepine/GABAA receptor function. The implications of these findings for research on mutant mice are discussed.
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Affiliation(s)
- R J Rodgers
- Behavioural Pharmacology Laboratory, School of Psychology University of Leeds, Leeds, UK.
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19
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Shishkina GT, Kalinina TS, Sournina NY, Saharov DG, Kobzev VF, Dygalo NN. Effects of antisense oligodeoxynucleotide to the alpha2A-adrenoceptors on the plasma corticosterone level and on elevated plus-maze behavior in rats. Psychoneuroendocrinology 2002; 27:593-601. [PMID: 11965357 DOI: 10.1016/s0306-4530(01)00095-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Antisense strategy was used to investigate the role of alpha2A-adrenoceptor (alpha2A-AR) subtype in anxiety-related behavior. A 18-mer phosphorothioate oligodeoxynucleotide (AS-ODN) complementary to the alpha2A-AR mRNA was administered to the adult male rats for 3 days (1 nmol/5 microl/day) into the region of locus coeruleus (LC). Control groups received infusions of either oligodeoxynucleotide of a random sequence (RS-ODN) or saline. Treatment with AS-ODN significantly reduced the levels of alpha2A-AR mRNA in the brain stem. At the same time, AS-ODN treatment caused only a small reduction in [(3)H]clonidine binding (by 26-32%) in the brain stem which was not significant. Compared to both RS-ODN and saline controls, treatment with AS-ODN significantly increased the percentage of open arm entries in the elevated plus-maze while the total number of arm entries was unaltered. Also, AS-ODN treatment elevated basal levels of plasma corticosterone by 217% and 96% compared to both RS-ODN and saline controls. These changes in the hormone concentrations were at a level of marginal significance (p<0.1 versus random group). Taken together, the data indicate that administration of AS-ODN against alpha2A-ARs in the LC significantly reduced expression of alpha2A-AR mRNA in brain stem, moderately increased plasma corticosterone and had anxiolytic-like effect in the elevated plus-maze.
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Affiliation(s)
- G T Shishkina
- Institute of Cytology and Genetics, RAS, Novosibirsk 630090, Russia.
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20
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Olsen CK, Hogg S, Lapiz MDS. Tonic immobility in guinea pigs: a behavioural response for detecting an anxiolytic-like effect? Behav Pharmacol 2002; 13:261-9. [PMID: 12218506 DOI: 10.1097/00008877-200207000-00002] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Tonic immobility (TI) is considered to be an innate fear response characterized by a temporary state of profound and reversible motor inhibition. TI occurs in a wide range of species in a predator-prey confrontation and is hypothesized to be a terminal defence response occurring when there is physical contact between prey and predator. The objective of the present study was to investigate the validity of the TI model in guinea pigs for detection of anxiolytic and/or antidepressant drug activity. Compounds that reduced TI include the serotonin (5-HT) releaser fenfluramine, the 5-HT(1A) receptor agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and buspirone, the 5-HT(2C/2B) receptor antagonist SB206553, the 5-HT(2A) receptor antagonist MDL 100.151 -- but only at doses thought also to inhibit 5-HT(2C) receptors--the noradrenaline (NA) reuptake inhibitor desipramine, the benzodiazepine inverse agonist FG-7142, the alpha(2)-adrenergic receptor antagonist yohimbine, the neurokinin (NK)(1) receptor antagonist L-733.060, and the NK(2) receptor antagonist SR-48968. Compounds that increased TI include the benzodiazepine agonists diazepam and alprazolam, and the alpha(2)-adrenergic receptor agonist clonidine. The selective 5-HT reuptake inhibitors citalopram, paroxetine and fluoxetine, the 5-HT(1A) receptor antagonist WAY100.635, the 5-HT(2C) receptor agonist MK-212, the 5-HT/NA reuptake inhibitor imipramine, the NA reuptake inhibitor talopram, the benzodiazepine antagonist flumazenil, the alpha(2)-adrenergic receptor antagonist idazoxan and the psychostimulant amphetamine did not have any effect. These findings indicate that the serotonergic, noradrenergic and neurokinin systems are involved in mediating or modulating TI behaviour in guinea pigs. The potential of TI as a behaviour for detecting anxiolytic-like effect may be questioned due to the contradictory effect of the benzodiazepine ligands, which may be attributed to the sedative and/or ataxic effects of the compounds. Nevertheless, there is preclinical evidence suggesting that 5-HT(1A) receptor agonists, 5-HT(2C) receptor antagonists and NK(1) and NK(2) receptor antagonists possess anxiolytic potential. Only when results of clinical investigations of the anxiolytic potential of non-benzodiazepine ligands (for example the NK receptor antagonists) are available, will it be possible to determine fully the predictive validity of the TI model.
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Affiliation(s)
- C K Olsen
- Pharmalogical Research, H. Lundbeck A/S, Valby, Copenhagen, Denmark.
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21
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Effects of antisense to the (alpha)2A-adrenoceptors administered into the region of the locus ceruleus on behaviors in plus-maze and sexual behavior tests in sham-operated and castrated male rats. J Neurosci 2001. [PMID: 11160451 DOI: 10.1523/jneurosci.21-02-00726.2001] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Clinical and experimental findings have implicated brain alpha2-adrenoceptors in the regulation of many physiological functions, including sexual activity and stress-related behavior. However, which subtypes of the three alpha2-adrenoceptors that have now been cloned (alpha2A, alpha2B, and alpha2C) are involved in these controls have yet to be established. Here, we investigated the contribution of alpha2A-adrenoceptors of the locus ceruleus, the principal source of brain noradrenaline, to exploratory and sexual behaviors. Using administration of antisense oligodeoxynucleotide to inhibit the receptor expression, we found that reductions in brainstem alpha2A-adrenoceptor mRNA levels and alpha2-adrenoceptor densities induced by antisense treatment were not accompanied by any changes in the major characteristics of male sexual activity, such as mount latencies and numbers of mounts. However, in sexual behavior tests, antisense-treated male rats had decreased numbers of rearings and thus have higher percentages of behaviors positively correlated with sexual activity. Besides, antisense-treated animals had decreased anxiety in plus-maze tests. The data demonstrate that inhibition of alpha2A-adrenoceptor expression in the region of the locus ceruleus has an anxiolytic-like effect and facilitates male's attention to female in sexual behavior test.
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22
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Lepicard EM, Venault P, Perez-Diaz F, Joubert C, Berthoz A, Chapouthier G. Balance control and posture differences in the anxious BALB/cByJ mice compared to the non anxious C57BL/6J mice. Behav Brain Res 2000; 117:185-95. [PMID: 11099772 DOI: 10.1016/s0166-4328(00)00304-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A relation between anxiety disorders and balance control dysfunctions has been observed in many studies in humans. A mismatch in the integration of sensory inputs could trigger these disturbances. Very few experimental animal procedures have been designed to study the functional link between anxiety and balance control. A task was therefore developed, challenging the visual, vestibular and somesthesic sensory systems in mice. The test, called the 'rotating beam', gave an accurate assessment of balance control and the posture, using sensitive measures (number of falls and imbalances, position of tail and trunk). Striking differences were observed between the two inbred strains of mice known to have radically different anxiety-related behaviour. The highly anxious strain, BALB/cByJ, performed poorly compared to the non anxious strain, C57BL/6J. Balance control and postural abilities of anxious mice were improved by acute anxiolytic diazepam treatment. Lower behavioural performance level was registered in non anxious mice given anxiogenic beta-CCM treatment. The findings account for a strong relationship between anxiety and balance control in mice. Finally, the highly sensitive procedure proved to be well suited to the study of functional links between anxiety and sensorimotor processes.
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Affiliation(s)
- E M Lepicard
- CNRS UMR 7593 'Personnalité et conduites adaptatives', CHU Pitié-Salpêtrière, 91, bd de l'Hôpital, 75013, cedex 13, Paris, France.
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23
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Lepicard EM, Joubert C, Hagneau I, Perez-Diaz F, Chapouthier G. Differences in anxiety-related behavior and response to diazepam in BALB/cByJ and C57BL/6J strains of mice. Pharmacol Biochem Behav 2000; 67:739-48. [PMID: 11166064 DOI: 10.1016/s0091-3057(00)00419-6] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The study in an ethological perspective of inbred strains of mice offers a more accurate description of anxiety-related behavior. In this context, behavioral performances of the BALB/cByJ and C57BL/6J strains were systematically compared in the staircase test, the light/dark test and the elevated plus maze test. A rarely used variable, the latency of the first entry in the dark box, was also recorded in the light/dark test. A new statistical approach to this measure meant that specific avoidance strategies could be differentiated in the two strains. A study of the behavioral responses of the two strains given treatment with diazepam, a widely used anxiolytic compound, was also carried out. Results showed substantial differences between BALB/cByJ and C57BL/6J strains. C57BL/6J mice had high baseline activity and exploration of a new environment, suggesting a low level of anxiety. BALB/cByJ mice displayed defensive and protective behavior, with limited exploration of the new environment together with low locomotor activity. The response to diazepam was also different for each strain: C57BL/6J mice showed higher sensitivity to diazepam treatment than did BALB/cByJ mice.
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Affiliation(s)
- E M Lepicard
- CNRS UMR 7593, "Personnalité et conduites adaptatives", CHU Pitié-Salpêtrière, 91, Bd de l'Hôpital, 75013, Paris, France.
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24
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Holmes A, Parmigiani S, Ferrari PF, Palanza P, Rodgers RJ. Behavioral profile of wild mice in the elevated plus-maze test for anxiety. Physiol Behav 2000; 71:509-16. [PMID: 11239669 DOI: 10.1016/s0031-9384(00)00373-5] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Systematic observations of the defensive behavior of wild rodents have greatly informed the experimental study of anxiety and its neural substrates in laboratory animals. However, as the former work has been almost exclusively carried out in rats, few data are available concerning the reactivity of wild mice to standardized tests of anxiety-related behavior. In the present experiments, we employed ethological measures to examine the behavioral responses of a wild-derived population of house mice (Mus musculus) in the elevated plus-maze. In direct comparisons with laboratory Swiss mice, male wild mice exhibited substantially elevated levels of exploratory activities and an overall "preference" for the open arms of the plus-maze. On re-exposure to the plus-maze, male wild mice showed further increases in open arm exploration, while Swiss mice showed a marked shift to the enclosed parts of the plus-maze. Tested over a single session, female wild mice also exhibited a profile of high open arm exploration, but showed levels of exploratory behaviors and locomotor activity similar to female Swiss counterparts. While exploratory patterns in wild mice show similarities to profiles seen in certain laboratory strains (e.g., BALB/c), wild mice displayed a number of additional behaviors that are unprecedented in plus-maze studies with laboratory mice. These included actual and attempted jumps from the maze, spontaneous freezing, and exploration of the upper ledges of the closed arms. Thus, while in conventional terms the behavior of wild mice was consistent with one of low anxiety-like behavior, the presence of these unique elements instead indicates a profile more accurately characterized by high reactivity and escape motivation. We discuss how the use of an ethological approach to measuring plus-maze behavior can support accurate interpretation of other exceptional profiles in this test, such as those possibly arising from phenotyping of transgenic and gene knockout mice.
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Affiliation(s)
- A Holmes
- Dipartimento di Biologia Evolutiva e Funzionale, Universita di Parma, Viale di Scienze, 43100, Parma, Italy.
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25
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Zarrindast MR, Homayoun H, Babaie A, Etminani A, Gharib B. Involvement of adrenergic and cholinergic systems in nicotine-induced anxiogenesis in mice. Eur J Pharmacol 2000; 407:145-58. [PMID: 11050302 DOI: 10.1016/s0014-2999(00)00628-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In the present study, the effect of alpha-adrenoceptor agents on response to nicotine in an anxiety model (elevated plus-maze) in mice was investigated. Administered nicotine reduced indices of anti-anxiety behaviour (percent open-arm time (%open-arm time) and percent open-arm entries (%open-arm entry)) and increased indices of anxiety behaviour (protected stretched attention posture and percent of protected head dipping (%protected dipping)), indicating that nicotine elicits an anxiogenic response. This response to the drug was obtained 7 min but not 30 min after drug injection and with doses of 0.25 and 0.5 mg/kg. Nicotinic receptor antagonists mecamylamine (0.5 and 1 mg/kg) and hexamethonium (5 and 10 mg/kg) reduced the response induced by nicotine (0.25 mg/kg). Mecamylamine (1 mg/kg; decreased %open-arm entry and increased protected stretched attention posture) and hexamethonium (10 mg/kg; decreased %open-arm time) showed an anxiogenic-like profile. A muscarinic receptor antagonist, atropine (2.5 and 5 mg/kg), did not alter the nicotine response but elicited an anxiogenic effect by itself. The alpha(1)-adrenoceptor antagonist prazosin (0.25 and 0.5 mg/kg), but not the alpha(1)-adrenoceptor agonist, phenylephrine (4 and 6 mg/kg), reversed the nicotine effect. Single administration of phenylephrine (6 mg/kg) increased %open-arm time, while prazosin did not alter the anxiety behaviour. The alpha(2)-adrenoceptor agonist clonidine (0.001 and 0.01 mg/kg), induced complete immobility when administered in combination with nicotine. However, an alpha(2)-adrenoceptor antagonist, yohimbine (0.5 and 1 mg/kg), appeared to reverse the nicotine response, but did not show interaction with nicotine's effect. Clonidine did not elicit any effect, but yohimbine (1 mg/kg) increased %open-arm entry and %open-arm time by itself. It can be concluded that certain doses of nicotine (0.25 and 0.5 mg/kg) 7 min after their injection induce an anxiogenic effect through nicotinic mechanism(s), and that involvement of alpha(1)- but not alpha(2)-adrenoceptors in the response to nicotine seems likely.
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Affiliation(s)
- M R Zarrindast
- Department of Pharmacology, Medical School, Tehran University of Medical Sciences, PO Box 13145-784, Tehran, Iran
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26
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Wall PM, Messier C. U-69,593 microinjection in the infralimbic cortex reduces anxiety and enhances spontaneous alternation memory in mice. Brain Res 2000; 856:259-80. [PMID: 10677636 DOI: 10.1016/s0006-8993(99)01990-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present report investigated the contributions of the ventromedial prefrontal cortex to the control of spontaneous alternation/working memory and anxiety-related behaviour. In Experiment 1, we examined the effects of microinjections of the selective kappa(1) receptor agonist, U-69,593, in the infralimbic cortex (IL) of CD-1 mice on several ethologically-derived anxiety indices in the elevated plus-maze (EPM) and defensive/withdrawal (D/W) anxiety in the open field, as well as on memory in the EPM transfer-latency (T-L) test and implicit spontaneous alternation memory (SAP) in the Y-maze. In week 1, pretreatment with one injection of vehicle, 1, 10 or 25 nmol/1.0 microliter U-69,593 in the IL dose-dependently prolonged T-L and produced a dose-dependent anxiolytic behavioural profile in the first EPM trial. Following a 24-h delay, the same mice were given a drug-free second trial in the EPM tests of T-L memory and anxiety. Whereas T-L memory was not disturbed, small but detectable carry-over effects were observed in trial-2 EPM behaviour relative to vehicle-treated animals. In week 2, the same groups of mice were again pretreated with one injection of the same doses of U-69,593 in the IL and given a D/W test in an open field, followed immediately by an 8-min SAP trial in the Y-maze. The smallest U-69,593 dose was anxiolytic in the D/W test, and SAP/working memory was dose-dependently enhanced in the Y-maze. In Experiment 2, we evaluated whether 0.5 microliter volume microinjections would produce comparable behavioural and carry-over effects in the IL of three new groups of CD-1 mice, in the event that the 1.0 microl volume injections used in Experiment 1 diffused beyond the IL and therefore may have confounded some effects. Experiment 2 procedures were carried out in the same manner as in Experiment 1, except the animals were tested in reverse order. Thus in week 1, SAP memory was tested in the Y-maze followed by D/W anxiety in the open field for half of the animals in each group, and the other half was tested in reverse order. In week 2, T/L memory and anxiety were tested in the EPM in 2 trials as described in Experiment 1. Pretreatment with one injection of vehicle, 10 or 25 nmol/0.5 microliter U-69,593 in the IL reduced D/W anxiety and enhanced SAP memory regardless of testing order in week 1. In week 2, the same groups of mice were again pretreated with one injection of the same doses of U-69,593 in 0.5 microliter volumes in the IL and tested in the EPM. In a similar fashion to Experiment 1, U-69,593 dose-dependently prolonged T/L and produced an anxiolytic behavioural profile in the first EPM trial. Following a 24-h delay, T/L recall memory was again not significantly influenced, but a robust anxiolytic behavioural profile was observed in the second drug-free anxiety trial in the EPM relative to vehicle-treated animals. Results are discussed relative to a) injection volumes and testing order, b) the possible influence kappa receptors may exert on neurochemical responsivity to anxiety-provoking environments in the IL area of the mPFC, c) the possibility that kappa-mediated anxiolysis from the IL in CD-1 mice results from interactions with neurochemical systems involved in the blunting of incoming anxiety-provoking information, d) evidence that SAP memory may be an implicit subtype of working memory, and e) the possibility that IL implicit working memory processes may modulate the induction and expression of anxiety-related behaviour.
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Affiliation(s)
- P M Wall
- School of Psychology, University of Ottawa, Vanier: Room 215, Ottawa, Canada.
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27
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Millan MJ, Newman-Tancredi A, Audinot V, Cussac D, Lejeune F, Nicolas JP, Cogé F, Galizzi JP, Boutin JA, Rivet JM, Dekeyne A, Gobert A. Agonist and antagonist actions of yohimbine as compared to fluparoxan at alpha(2)-adrenergic receptors (AR)s, serotonin (5-HT)(1A), 5-HT(1B), 5-HT(1D) and dopamine D(2) and D(3) receptors. Significance for the modulation of frontocortical monoaminergic transmission and depressive states. Synapse 2000; 35:79-95. [PMID: 10611634 DOI: 10.1002/(sici)1098-2396(200002)35:2<79::aid-syn1>3.0.co;2-x] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Herein, we evaluate the interaction of the alpha(2)-AR antagonist, yohimbine, as compared to fluparoxan, at multiple monoaminergic receptors and examine their roles in the modulation of adrenergic, dopaminergic and serotonergic transmission in freely-moving rats. Yohimbine displays marked affinity at human (h)alpha(2A)-, halpha(2B)- and halpha(2C)-ARs, significant affinity for h5-HT(1A), h5-HT(1B), h5-HT(1D), and hD(2) receptors and weak affinity for hD(3) receptors. In [(35)S]GTPgammaS binding protocols, yohimbine exerts antagonist actions at halpha(2A)-AR, h5-HT(1B), h5-HT(1D), and hD(2) sites, yet partial agonist actions at h5-HT(1A) sites. In vivo, agonist actions of yohimbine at 5-HT(1A) sites are revealed by WAY100,635-reversible induction of hypothermia in the rat. In guinea pigs, antagonist actions of yohimbine at 5-HT(1B) receptors are revealed by blockade of hypothermia evoked by the 5-HT(1B) agonist, GR46,611. In distinction to yohimbine, fluparoxan shows only modest partial agonist actions at h5-HT(1A) sites versus marked antagonist actions at halpha(2)-ARs. While fluparoxan selectively enhances hippocampal noradrenaline (NAD) turnover, yohimbine also enhances striatal dopamine (DA) turnover and suppresses striatal turnover of 5-HT. Further, yohimbine decreases firing of serotonergic neurones in raphe nuclei, an action reversed by WAY100,635. Fluparoxan increases extracellular levels of DA and NAD, but not 5-HT, in frontal cortex. In analogy, yohimbine enhances FCX levels of DA and NAD, yet suppresses those of 5-HT, the latter effect being antagonized by WAY100,635. The induction by fluoxetine of FCX levels of 5-HT, DA, and NAD is potentiated by fluparoxan. Yohimbine likewise facilitates the influence of fluoxetine upon DA and NAD levels, but not those of 5-HT. In conclusion, the alpha(2)-AR antagonist properties of yohimbine increase DA and NAD levels both alone and in association with fluoxetine. However, in contrast to the selective alpha(2)-AR antagonist, fluparoxan, the 5-HT(1A) agonist actions of yohimbine suppress 5-HT levels alone and underlie its inability to augment the influence of fluoxetine upon 5-HT levels.
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MESH Headings
- Adrenergic alpha-2 Receptor Agonists
- Adrenergic alpha-2 Receptor Antagonists
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Antidepressive Agents/pharmacology
- Body Temperature/drug effects
- Frontal Lobe/drug effects
- Frontal Lobe/physiology
- Guinea Pigs
- Hippocampus/drug effects
- Hippocampus/physiology
- Humans
- Mice
- Neurons/drug effects
- Neurons/physiology
- Piperoxan/analogs & derivatives
- Piperoxan/pharmacology
- Pyrroles/pharmacology
- Rats
- Receptor, Serotonin, 5-HT1B
- Receptor, Serotonin, 5-HT1D
- Receptors, Dopamine D2/drug effects
- Receptors, Dopamine D2/physiology
- Receptors, Dopamine D3
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Receptors, Serotonin, 5-HT1
- Swine
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- Yohimbine/pharmacology
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Affiliation(s)
- M J Millan
- Psychopharmacology Department, Institut de Recherches Servier, Centre de Recherches de Croissy, 125, Chemin de Ronde, 78290-Croissy-sur-Seine, Paris, France
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28
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Promises and Limitations of Transgenic and Knockout Mice in Modeling Psychiatric Symptoms. CONTEMPORARY ISSUES IN MODELING PSYCHOPATHOLOGY 2000. [DOI: 10.1007/978-1-4757-4860-4_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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Henry B, Fox SH, Peggs D, Crossman AR, Brotchie JM. The alpha2-adrenergic receptor antagonist idazoxan reduces dyskinesia and enhances anti-parkinsonian actions of L-dopa in the MPTP-lesioned primate model of Parkinson's disease. Mov Disord 1999; 14:744-53. [PMID: 10495035 DOI: 10.1002/1531-8257(199909)14:5<744::aid-mds1006>3.0.co;2-7] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Dopamine replacement therapy in patients with Parkinson's disease is plagued by the emergence of abnormal involuntary movements known as L-dopa-induced dyskinesias. It has been demonstrated that yohimbine can reduce L-dopa-induced dyskinesia in the MPTP-lesioned primate model of Parkinson's disease. Yohimbine is, among other things, an alpha-adrenergic receptor antagonist. In this study, we demonstrate that the selective and potent alpha2-adrenergic receptor antagonist idazoxan reduces L-dopa-induced dyskinesia in the MPTP-lesioned marmoset model of Parkinson's disease. The alpha2-adrenergic receptor antagonists rauwolscine and yohimbine also reduce L-dopa-induced dyskinesia. Furthermore, we demonstrate that coadministration of idazoxan with L-dopa can provide an anti-parkinsonian action more than twice the length of that seen with L-dopa alone. However, idazoxan as a monotherapy displayed no anti-parkinsonian actions. We propose that idazoxan in combination with L-dopa may provide a novel approach to the treatment of Parkinson's disease that will not only reduce the dyskinetic side effects, but extend the anti-parkinsonian actions of L-dopa. Idazoxan, as an adjunct to dopamine replacement, may prove useful in the treatment of parkinsonian patients at all stages of disease progression.
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Affiliation(s)
- B Henry
- Organon Laboratories Limited, Department of Pharmacology, Lanarkshire, Scotland, UK
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30
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Ferrari PF, Palanza P, Parmigiani S, Rodgers RJ. Interindividual variability in Swiss male mice: relationship between social factors, aggression, and anxiety. Physiol Behav 1998; 63:821-7. [PMID: 9618005 DOI: 10.1016/s0031-9384(97)00544-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the present study we carried out a series of experiments in Swiss albino male mice to investigate a) the effects of previous social experience on the levels of anxiety in the elevated plus-maze (EPM) and b) whether the response of males in the EPM differs in relation to the different social status. In Experiment 1 we tested in the EPM male mice that received different social experience. Results showed that individually housing generally increased measures of anxiety in the EPM compared with the group-housing condition. Moreover, aggressive males, screened during dyadic encounters in a neutral cage, displayed the highest levels of anxiety relative to the other experimental conditions. In Experiment 2 male mice remained group-housed and were observed to record their social status. Results showed that those animals rated as socially dominant displayed a higher level of EPM anxiety relative to subordinates. From an ethological perspective our findings may be interpreted in terms of coping strategies, with aggressive/dominant animals typified by higher levels of risk assessment and open-arm avoidance than defensive/subordinate animals.
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Affiliation(s)
- P F Ferrari
- Dipartimento di Biologia Evolutiva e Funzionale, Università di Parma, Italy.
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31
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Abstract
The elevated plus-maze test has been in use as a rodent model of anxiety for a decade, and is representative of those tests that are based upon the study of spontaneous behaviour patterns and which have high ecological validity. The origins of the test in studies of the relationship between exploration and fear are reviewed, and attention is drawn to the distinct possibility that variation in the pharmacosensitivity of the procedure may be attributable to often extreme methodological variation between laboratories. In considering further this issue, attention is also drawn to the need to collect data under constant test conditions and to provide the minimum database necessary to reach conclusions regarding the behavioural specificity of drug action. Recent research, which has extended the conventional plus-maze scoring technique to include specific behavioural acts and postures (in particular, those relating to defensive behaviour), is described. The value of such an ethological approach to the plus-maze is then exemplified with original data that demonstrate behaviourally selective, anti-anxiety effects of the GABAA receptor agonist, muscimol (0.125-1.0 mg/kg). It is concluded that, when used appropriately, the elevated plus-maze test can be a very valuable tool in drug screening and in the study of the neurobiology of anxiety and defence. More attention to behaviour and somewhat less emphasis on test simplicity and convenience would seem to be warranted.
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Affiliation(s)
- R J Rodgers
- Department of Psychology, University of Leeds, UK.
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32
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Hendrie CA, Eilam D, Weiss SM. Effects of diazepam and buspirone on the behaviour of wild voles (Microtus socialis) in two models of anxiety. Pharmacol Biochem Behav 1997; 58:573-6. [PMID: 9300621 DOI: 10.1016/s0091-3057(97)00278-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Exploration models of anxiety rely almost universally on the use of laboratory species. Furthermore, the spontaneous patterns of locomotion displayed are often interpreted as being an expression of antipredator defense. However, there is no direct link between the experience of these animals and the proposed motivation for their behaviour. To address this problem, the behaviour of wild trapped voles (Microtus socialis), a small-rodent species that is heavily predated upon, was examined in the elevated plus-maze and the black/white exploration model. It was hypothesised that the patterns of locomotion in these exploration models of anxiety should be similar to those reported for laboratory animals if the reactions of the laboratory animals are related to antipredator defense. Data revealed that voles show a similar preference for the protected areas in these models (closed arms or dark section) and that this preference can be modified by buspirone and diazepam. Interestingly, although the effective doses of each drug was the same within each model, it differed between models, with the minimum effective doses of these compounds being lower in the black/white exploration model (1 mg/kg) than in the elevated plus-maze (4 mg/kg). These data provide valuable information concerning the actions of anxiolytic compounds in wild trapped animals as assessed by formal laboratory models and provide useful verification that findings in these models may be generalised to species other than laboratory rodents.
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Affiliation(s)
- C A Hendrie
- Department of Psychology, University of Leeds, West Yorkshire, United Kingdom.
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33
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Cao BJ, Rodgers RJ. Comparative behavioural profiles of buspirone and its metabolite 1-(2-pyrimidinyl)-piperazine (1-PP) in the murine elevated plus-maze. Neuropharmacology 1997; 36:1089-97. [PMID: 9294974 DOI: 10.1016/s0028-3908(97)00094-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
It has been suggested that in vivo formation of the metabolite 1-(2-pyrimidinyl)-piperazine (1-PP) may be a major drawback in the use of buspirone as an anti-anxiety agent. To test this hypothesis, the effects of buspirone, alone or with proadifen (an inhibitor of liver microsomal enzymes) pretreatment, were contrasted with those of 1-PP in the murine elevated plus-maze test of anxiety. At 3.0 mg/kg (but not lower doses), buspirone per se had modest anxiolytic-like effects (increased percentage of open arm entries; reduced stretched-attend postures and flatback approach) that were associated with increased grooming and immobility. However, in proadifen-pretreated mice, buspirone produced behavioural depression only, with marked effects evident both at 1.0 and 3.0 mg/kg. As proadifen blocks the biotransformation of buspirone to 1-PP, these data suggest that any anxiolytic activity of buspirone in the murine plus-maze may be attributable to its principal active metabolite. Consistent with this hypothesis, 1-PP (0.5-13.5 mg/kg) produced dose-dependent anti-anxiety effects on both conventional and ethological measures that were not confounded by motoric impairment. Results are discussed in relation to biochemical and electrophysiological studies suggesting that 1-PP has a direct action at 5-HT1A receptors.
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Affiliation(s)
- B J Cao
- Department of Psychology, University of Leeds, U.K
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34
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Rodgers RJ, Cutler MG, Jackson JE. Behavioural effects in mice of subchronic chlordiazepoxide, maprotiline and fluvoxamine. II. The elevated plus-maze. Pharmacol Biochem Behav 1997; 57:127-36. [PMID: 9164563 DOI: 10.1016/s0091-3057(96)00134-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In view of apparent commonalities in the aetiology, symptomatology, and pharmacotherapy of anxiety and depressive disorders, the present study compares the effects of the benzodiazepine, chlordiazepoxide (1.0-8.0 mg/kg), the selective noradrenaline (NA) reuptake inhibitor, maprotiline (0.5-10.0 mg/kg), and the serotonin (5-HT)-selective reuptake inhibitor, fluvoxamine (2.0-8.0 mg/kg), on the behaviour of mice in the elevated plus-maze test of anxiety. To more accurately reflect the clinical situation, subjects were treated daily for 21 days prior to testing, and comprehensive behavioural profiles were obtained through the application of an ethological scoring technique. Results show that subchronic treatment with chlordiazepoxide produced clear anxiolytic-like effects at the highest dose tested, coupled with an inhibition of risk assessment over the entire dose range. With the exception of risk assessment measures, anxiolytic-like effects were also seen with a low dose (0.5 mg/kg) of maprotiline: these effects were lost at higher doses. In contrast to these data, fluvoxamine produced minimal behavioural change under present test conditions. Findings are discussed in relation to the relative efficacy of selective monoamine. reuptake inhibitors in the treatment of anxiety disorders, and the nature of anxiety evoked in mice by exposure to the elevated plus-maze.
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Affiliation(s)
- R J Rodgers
- Department of Psychology, University of Leeds, UK
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35
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Abstract
In the field of anxiety research, animal models are used as screening tools in the search for compounds with therapeutic potential and as simulations for research on mechanism underlying emotional behaviour. However, a solely pharmacological approach to the validation of such tests has resulted in distinct problems with their applicability to systems other than those involving the benzodiazepine/GABAA receptor complex. In this context, recent developments in our understanding of mammalian defensive behaviour have not only prompted the development of new models but also attempts to refine existing ones. The present review focuses on the application of ethological techniques to one of the most widely used animal models of anxiety, the elevated plus-maze paradigm. This fresh approach to an established test has revealed a hitherto unrecognized multidimensionality to plus-maze behaviour and, as it yields comprehensive behavioural profiles, has many advantages over conventional methodology. This assertion is supported by reference to recent work on the effects of diverse manipulations including psychosocial stress, benzodiazepines, GABA receptor ligands, neurosteroids, 5-HT1A receptor ligands, and panicolytic/panicogenic agents. On the basis of this review, it is suggested that other models of anxiety may well benefit from greater attention to behavioural detail.
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Affiliation(s)
- R J Rodgers
- Department of Psychology, University of Leeds, England.
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36
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Haller J, Makara GB, Kovács JL. The effect of alpha 2 adrenoceptor blockers on aggressive behavior in mice: implications for the actions of adrenoceptor agents. Psychopharmacology (Berl) 1996; 126:345-50. [PMID: 8878351 DOI: 10.1007/bf02247386] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effects of three alpha 2 adrenoceptor blockers (idazoxan, yohimbine and CH-38083) on isolation-induced aggressive behavior was studied in male mice. The three drugs produced different behavioral profiles. Idazoxan reduced aggressiveness dose-dependently by decreasing the duration of offensive/aggressive interactions and increasing the duration of defensive behaviors. The other two drugs produced only parts of the dual action of idazoxan: yohimbine affected mainly defensive behaviors, while CH-38083 affected only the time spent with fighting. Saline injections per se also influenced behavior and, in contrast to alpha 2 adrenoceptor blockers, induced an increase in aggressiveness. These results are different from those previously obtained in rats, which show bell-shaped dose-response curves in response to alpha 2 adrenoceptor blockers (small doses increased, while large doses decreased aggression). It is postulated that the strong behavioral reaction of mice to the injection per se may mask the aggression-heightening effects of small doses of alpha 2 adrenoceptor blockers in this species. A theory is also presented regarding the complexity of adrenoceptor interactions when both pre-, and postsynaptic alpha 2 adrenoceptors are blocked.
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Affiliation(s)
- J Haller
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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37
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Abstract
Despite or possibly by virtue of the fact that it is one of the most commonly used animal models of anxiety the Elevated Plus-Maze (EPM) results in a wide range of, often contradictory, results following pharmacological experiments. The responses from a questionnaire distributed to 65 groups that have published studies using the EPM in the past 3 years has, along with reference to published reports, enabled some conclusions regarding the influencing factors to be drawn. Some evidence for differential sensitivities between strains exists, with albino rats being more sensitive to the anxiolytic effects of 5-HT3 receptor antagonists and 5-HT1A receptor agonists than pigmented animals. Most important, however, is the manipulation of the animals prior to testing and the aversiveness of the test conditions themselves. Stressing animals before testing (e.g., by moving from holding to test room) or using more aversive test conditions (e.g., elevated light levels) increases sensitivity to potential anxiolytics. Animals that are habituated to gentle handling or tested in less aversive conditions (e.g., EPM with ledges) show reduced likelihood of anxiolytic responses with administration of 5-HT3 antagonists, 5-HT1A agonists, and benzodiazepines.
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Affiliation(s)
- S Hogg
- Psychopharmacology Research Unit, UMDS Division of Pharmacology, Guy's Hospital Medical School, London, UK
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38
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Johnson NJ, Rodgers RJ. Ethological analysis of cholecystokinin (CCKA and CCKB) receptor ligands in the elevated plus-maze test of anxiety in mice. Psychopharmacology (Berl) 1996; 124:355-64. [PMID: 8739551 DOI: 10.1007/bf02247441] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The literature on the effects of CCK receptor manipulations in animal models of anxiety is rife with inconsistency, and the data subject to a variety of methodological and interpretative difficulties. In the present paper, the effects of a range of CCK receptor ligands on anxiety in male mice have been assessed using an ethological version of the elevated plus-maze test. Compounds selected for study were the agonists, CCK-4 and CCK-8s (12.5-100 micrograms/kg), and the antagonists, devazepide, L-365, 260 and PD 135158 (1.0 microgram/kg-1.0 mg/kg). CCK-4 failed to produce any significant behavioural effects over the dose range tested, while treatment with the sulphated octapeptide, CCK-8s, induced signs of behavioural inhibition at 100 microgram/kg without altering anxiety-related indices. Furthermore, in contrast to the clear anxiolytic profile of diazepam (1 mg/kg), and despite the comprehensive behavioural profiles yielded by ethological analysis, all three CCK receptor antagonists studied (devazepide, L-365, 260 and PD 135158) were found to be without significant effect under present test conditions. Together, present findings provide little support for the involvement of CCK receptor mechanisms in anxiety and, in particular, the form of anxiety evoked in mice by exposure to a plus-maze.
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Affiliation(s)
- N J Johnson
- Department of Psychology, University of Leeds, UK
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39
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Rodgers RJ, Johnson NJ. Factor analysis of spatiotemporal and ethological measures in the murine elevated plus-maze test of anxiety. Pharmacol Biochem Behav 1995; 52:297-303. [PMID: 8577794 DOI: 10.1016/0091-3057(95)00138-m] [Citation(s) in RCA: 575] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Recent research employing the elevated plus-maze to assess anxiety in rodents has incorporated a variety of behavioral elements in addition to the standard parameters of entries onto and time spent in the aversive open arms. In the present study, we have used a large database comprising the behavioral profiles of 90 undrugged mice to examine the relationship between the standard spatiotemporal measures and a range of specific behaviors related to the defensive repertoire of the mouse. A factor analysis applied to the standard measures revealed two factors related to anxiety and locomotor activity. The simple addition of center time (an infrequently recorded measure) to the analysis yielded a third factor, most probably related to decision making. A large-scale factor analysis applied to all measures further confirmed the existence of factors related to anxiety, locomotor activity, and decision making, and revealed three further factors thought to represent risk assessment, vertical activity, and exploratory behavior. Thus, the inclusion of ethological measures not only confirmed prior knowledge based on a very limited range of measures, but also demonstrated the existence of additional behavioral dimensions. The potential applications of this knowledge are discussed.
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Affiliation(s)
- R J Rodgers
- Department of Psychology, University of Leeds, UK
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