1
|
Zvozilova A, Bukatova S, Koprdova R, Mach M. Evaluation of New Approaches to Depression Treatment Using an Animal Model of Pharmacoresistant Depression. Int J Mol Sci 2024; 25:5265. [PMID: 38791304 PMCID: PMC11121040 DOI: 10.3390/ijms25105265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
Depression is emerging as the predominant psychiatric disorder globally. Despite the wide availability of antidepressants, up to 30% of patients exhibit poor response to treatment, falling into the category of treatment-resistant depression (TRD). This underscores the need for the exploration of novel therapeutic options. Our work aims to study the effect of chronic administration of the pyridoindole derivative SMe1EC2M3, a triple reuptake inhibitor, and the combination of zoletil and venlafaxine under conditions of stress induced by a 4-week chronic mild stress (CMS) procedure in Wistar-Kyoto male rats as an animal model of TRD. Therefore, we investigated the possible effect of the selected compounds in four experimental groups, i.e., stress + vehicle, stress + venlafaxine, stress + zoletil + venlafaxine and stress + SMe1EC2M3. The following variables were assessed: anhedonia in sucrose preference test (SPT), spontaneous locomotion and exploration in open field test (OF), anxiety-like behavior in elevated plus maze test (EPM), motivation and depressive-like behavior in forced swim test (FST) and nociception in tail flick test. We also evaluated cognition, particularly recognition memory, in the novel object recognition test (NOR). Sucrose preference was significantly increased in the SMe1EC2M3 group (p < 0.05) in comparison with the venlafaxine animals. In the OF, we observed a significantly higher number of entries into both the central and peripheral zones in the venlafaxine (p < 0.05 central zone; p ≤ 0.05 periphery zone) and SMe1EC2M3 (p < 0.05 central zone; p < 0.05 periphery zone) groups compared to the venlafaxine + zoletil group. SMe1EC2M3 was able to significantly increase the time of climbing in FST (p < 0.05) in comparison with the venlafaxine and control groups. The NOR test revealed a significantly higher discrimination ratio in the SMe1EC2M3 group (p < 0.05) compared to the control and venlafaxine groups. Analyses of the tail flick test showed a significant increase in reaction time to painful stimuli in the SMe1EC2M3 group (p < 0.05) in comparison to both the control and venlafaxine groups. Our findings suggest that SMe1EC2M3 has the potential to ameliorate some behavioral changes associated with TRD, and the venlafaxine + zoletil combination treatment was not a promising treatment alternative in the animal model of TRD.
Collapse
Affiliation(s)
- Alexandra Zvozilova
- Centre of Experimental Medicine of the Slovak Academy of Sciences, Institute of Experimental Pharmacology and Toxicology, 841 04 Bratislava, Slovakia; (A.Z.); (S.B.); (R.K.)
- Department of Pharmacology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Stanislava Bukatova
- Centre of Experimental Medicine of the Slovak Academy of Sciences, Institute of Experimental Pharmacology and Toxicology, 841 04 Bratislava, Slovakia; (A.Z.); (S.B.); (R.K.)
| | - Romana Koprdova
- Centre of Experimental Medicine of the Slovak Academy of Sciences, Institute of Experimental Pharmacology and Toxicology, 841 04 Bratislava, Slovakia; (A.Z.); (S.B.); (R.K.)
| | - Mojmir Mach
- Centre of Experimental Medicine of the Slovak Academy of Sciences, Institute of Experimental Pharmacology and Toxicology, 841 04 Bratislava, Slovakia; (A.Z.); (S.B.); (R.K.)
| |
Collapse
|
2
|
Korlatowicz A, Pabian P, Solich J, Kolasa M, Latocha K, Dziedzicka-Wasylewska M, Faron-Górecka A. Habenula as a Possible Target for Treatment-Resistant Depression Phenotype in Wistar Kyoto Rats. Mol Neurobiol 2023; 60:643-654. [PMID: 36344870 PMCID: PMC9849162 DOI: 10.1007/s12035-022-03103-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 10/23/2022] [Indexed: 11/09/2022]
Abstract
The mechanisms of treatment-resistant depression (TRD) are not clear and are difficult to study. An animal model resembling human TRD is the Wistar Kyoto rat strain. In the present study, we focused on selecting miRNAs that differentiate rats of the WKY strain from Wistar Han (WIS) rats in two divisions of the habenula, the lateral and medial (LHb and MHb, respectively). Based on our preliminary study and literature survey, we identified 32 miRNAs that could be potentially regulated in the habenula. Six miRNAs significantly differentiated WKY rats from WIS rats within the MHb, and three significantly differentiated WKY from WIS rats within the LHb. Then, we selected relevant transcripts regulated by those miRNAs, and their expression in the habenular nuclei was investigated. For mRNAs that differentiated WKY rats from WIS rats in the MHb (Cdkn1c, Htr7, Kcnj9, and Slc12a5), their lower expression correlated with a higher level of relevant miRNAs. In the LHb, eight mRNAs significantly differentiated WKY from WIS rats (upregulated Htr4, Drd2, Kcnj5, and Sstr4 and downregulated Htr2a, Htr7, Elk4, and Slc12a5). These data indicate that several important miRNAs are expressed in the habenula, which differentiates WKY rats from WIS rats and in turn correlates with alterations in the expression of target transcripts. Of particular note are two genes whose expression is altered in WKY rats in both LHb and MHb: Slc12a5 and Htr7. Regulation of KCC2 via the 5-HT7 receptor may be a potential target for the treatment of TRD.
Collapse
Affiliation(s)
- Agata Korlatowicz
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Paulina Pabian
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Joanna Solich
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Magdalena Kolasa
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Katarzyna Latocha
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Marta Dziedzicka-Wasylewska
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Agata Faron-Górecka
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
| |
Collapse
|
3
|
Maternal stress and vulnerability to depression: coping and maternal care strategies and its consequences on adolescent offspring. Transl Psychiatry 2022; 12:463. [PMID: 36333302 PMCID: PMC9636172 DOI: 10.1038/s41398-022-02220-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 09/30/2022] [Accepted: 10/12/2022] [Indexed: 11/06/2022] Open
Abstract
Depressive mothers often find mother-child interaction to be challenging. Maternal stress may further impair mother-child attachment, which may increase the risk of negative developmental consequences. We used rats with different vulnerability to depressive-like behavior (Wistar and Kyoto) to investigate the impact of stress (maternal separation-MS) on maternal behavior and adolescent offspring cognition. MS in Kyoto dams increased pup-contact, resulting in higher oxytocin levels and lower anxiety-like behavior after weaning, while worsening their adolescent offspring cognitive behavior. Whereas MS in Wistar dams elicited higher quality of pup-directed behavior, increasing brain-derived neurotrophic factor (BDNF) in the offspring, which seems to have prevented a negative impact on cognition. Hypothalamic oxytocin seems to affect the salience of the social environment cues (negatively for Kyoto) leading to different coping strategies. Our findings highlight the importance of contextual and individual factors in the understanding of the oxytocin role in modulating maternal behavior and stress regulatory processes.
Collapse
|
4
|
Validation of chronic mild stress in the Wistar-Kyoto rat as an animal model of treatment-resistant depression. Behav Pharmacol 2020; 30:239-250. [PMID: 30204592 DOI: 10.1097/fbp.0000000000000431] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A recent review proposed four criteria for an animal model of treatment-resistant depression (TRD): a phenotypic resemblance to a risk factor for depression; enhanced response to stress; nonresponse to antidepressant drugs and response to treatments effective in TRD, such as deep brain stimulation (DBS) of the prefrontal cortex or ketamine. Chronic mild stress (CMS) provides a valid model of depression; the Wistar-Kyoto (WKY) rat is considered to be nonresponsive to antidepressant drugs. Here, we applied CMS to WKY rats. WKY and Wistar rats were exposed to CMS, then treated with saline, imipramine, citalopram or venlafaxine. After 5 weeks of CMS and 3 weeks of drug treatment, all WKY groups were implanted unilaterally with DBS electrodes in the prefrontal cortex, and examined in sucrose intake, elevated plus maze (EPM; decreased entries and time in the open arms) and novel object recognition (decreased exploration) tests, following 2×2 h of DBS. CMS decreased sucrose intake, open arm entries on the EPM, and object recognition. Relative to Wistars, WKY rats showed evidence of increased emotionality in the EPM and novel object recognition tests, and a greater impact of CMS on body weight gain and open arm entries. Wistars responded to drug treatment with an increase in sucrose intake but WKY were nonresponsive to drug treatment on all three behavioural tests. With one exception, DBS reversed the anhedonic, anxiogenic and dyscognitive effects of CMS in all groups of WKY rats. In a further experiment, subacute ketamine (10 mg/kg) also normalized behaviour on all three tests. We conclude that WKY rats subjected to CMS meet all four criteria for a valid model of TRD, and provide a basis for studying the mechanism of action of DBS.
Collapse
|
5
|
Papp M, Gruca P, Faron-Górecka A, Kusmider M, Willner P. Genomic Screening of Wistar and Wistar-Kyoto Rats Exposed to Chronic Mild Stress and Deep Brain Stimulation of Prefrontal Cortex. Neuroscience 2019; 423:66-75. [DOI: 10.1016/j.neuroscience.2019.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/13/2022]
|
6
|
Rea K, Olango WM, Okine BN, Madasu MK, McGuire IC, Coyle K, Harhen B, Roche M, Finn DP. Impaired endocannabinoid signalling in the rostral ventromedial medulla underpins genotype-dependent hyper-responsivity to noxious stimuli. Pain 2014; 155:69-79. [DOI: 10.1016/j.pain.2013.09.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 08/18/2013] [Accepted: 09/09/2013] [Indexed: 12/20/2022]
|
7
|
Bianchi M, Fone KCF, Shah AJ, Atkins AR, Dawson LA, Heidbreder CA, Hagan JJ, Marsden CA. Chronic fluoxetine differentially modulates the hippocampal microtubular and serotonergic system in grouped and isolation reared rats. Eur Neuropsychopharmacol 2009; 19:778-90. [PMID: 19584022 DOI: 10.1016/j.euroneuro.2009.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 05/05/2009] [Accepted: 06/09/2009] [Indexed: 10/20/2022]
Abstract
Social isolation from weaning in rats produces behavioural and hippocampal structural changes at adulthood. Here, rats were group or isolation reared for eight-weeks. Following the initial four-week period of rearing, fluoxetine (10 mg/kg i.p.) was administered for 28 days. Changes in recognition memory, hippocampal monoamines, and cytoskeletal microtubules were investigated. Isolation-rearing for four- or eight-weeks produced recognition memory deficits that were not reversed by fluoxetine. Eight-weeks of isolation decreased alpha-tubulin acetylation (Acet-Tub) and the tyrosinated/detyrosinated alpha-tubulin ratio (Tyr/Glu-Tub), suggesting major alterations in microtubule dynamics and neuronal plasticity. In grouped rats, fluoxetine decreased Acet-Tub without changes in Tyr/Glu-Tub. In isolates, fluoxetine did not affect Acet-Tub but increased Tyr/Glu-Tub. Finally, fluoxetine altered serotonin metabolism in grouped, but not in isolated animals. Therefore, isolation-rearing changes the hippocampal responses of the serotonergic and microtubular system to fluoxetine. These findings show that early-life experience induces behavioural changes paralleled by alterations in cytoskeletal and neurochemical functions.
Collapse
Affiliation(s)
- Massimiliano Bianchi
- Institute of Neuroscience, School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK.
| | | | | | | | | | | | | | | |
Collapse
|
8
|
McDermott C, Kelly JP. Comparison of the behavioural pharmacology of the Lister-Hooded with 2 commonly utilised albino rat strains. Prog Neuropsychopharmacol Biol Psychiatry 2008; 32:1816-23. [PMID: 18727950 DOI: 10.1016/j.pnpbp.2008.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 07/23/2008] [Accepted: 08/02/2008] [Indexed: 10/21/2022]
Abstract
The use of animal models (particularly rats) in research for developing drugs for central nervous system diseases is well validated. However a range of strains are often utilised in these models. The Lister-Hooded (LH) strain is beginning to be increasingly used in preclinical investigations. Thus, the objective of the present study was to investigate the comparative behavioural pharmacology of this strain, with the two most widely used rat strains, namely the Sprague-Dawley (SD), and Wistar (W) strains. The tests used were the forced swim test (FST) for antidepressants, the amphetamine-locomotor activity test for antipsychotics, the elevated plus maze (EPM) for anxiolytics, as well as tests of general locomotor activity using home cage monitoring (HCM) and the open field test. Continuous HCM revealed a significantly higher daily activity and lower nocturnal activity for LH compared to the other strains; there were no strain-related differences in the open field test. In the FST, there were no strain differences in immobility time and a similar magnitude of desipramine-induced reduction in immobility across strains. In the locomotor activity test, control LH rats showed significantly higher activity whilst significant amphetamine-induced hyperactivity was seen only with the LH and W strains. In the EPM, control LH rats had a significantly larger percentage of open arm entries, whilst only the SD strain displayed a significant diazepam-induced increase in this parameter. These findings suggest that strain variation can cause markedly different results in behavioural pharmacological tests where locomotor activity plays a significant role, and should be taken into account when selecting a strain for evaluating the behavioural effects of psychotropic drugs. Such differences in locomotor activity in the LH strain could be accounted for by an altered diurnal pattern in this strain.
Collapse
Affiliation(s)
- Claire McDermott
- Department of Pharmacology and Therapeutics, University Road, NUI, Galway, Ireland
| | | |
Collapse
|
9
|
Bianchi M, Fone KFC, Azmi N, Heidbreder CA, Hagan JJ, Marsden CA. Isolation rearing induces recognition memory deficits accompanied by cytoskeletal alterations in rat hippocampus. Eur J Neurosci 2006; 24:2894-902. [PMID: 17116162 DOI: 10.1111/j.1460-9568.2006.05170.x] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Social isolation from weaning affects hippocampal structure and function in the rat. The intrinsic dynamic instability of the cytoskeletal microtubular system is essential for neuronal development and organization. Accordingly, the present paper investigated the effects of social isolation on hippocampal levels of alpha-tubulin isoforms associated with microtubule dynamics, the dendritic marker MAP-2 and alterations in locomotor activity and recognition memory. Male Lister Hooded rats (postnatal day 25-28) were housed either in groups or singly (isolated animals) for 30 days. Locomotor activity in a novel arena and novel object recognition were monitored in activity boxes. The hippocampus was dissected out 18 h after the novel object recognition task. Levels of alpha-tubulin isoforms and MAP-2 were analysed using Western blots. The experiments were conducted in duplicate, using two batches of rats obtained from different suppliers. Isolated animals were hyperactive and showed recognition memory deficits in the novel object recognition task. These behavioural alterations were accompanied by specific alterations in hippocampal alpha-tubulin isoforms and decreased MAP-2 expression. The results confirm that rearing rats in isolation produces hyperactivity and cognitive deficits. The behavioural alterations were accompanied by hippocampal cytoskeletal changes consistent with microtubule stabilization, and by decreased MAP-2 expression. These findings are indicative of an abnormal development of synaptic connections and/or reductions in neuronal cell number. The developmental structural abnormalities in the hippocampus may contribute to the cognitive impairments which result from isolation rearing in rats.
Collapse
Affiliation(s)
- M Bianchi
- Institute of Neuroscience, School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
| | | | | | | | | | | |
Collapse
|
10
|
Burgdorf J, Panksepp J, Brudzynski SM, Kroes R, Moskal JR. Breeding for 50-kHz positive affective vocalization in rats. Behav Genet 2005; 35:67-72. [PMID: 15674533 DOI: 10.1007/s10519-004-0856-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Adolescent and adult rats exhibit at least two distinct ultrasonic vocalizations that reflect distinct emotional states. Rats exhibit 22-kHz calls during social defeat, drug withdrawal, as well as in anticipation of aversive events. In contrast, 50-kHz calls are exhibited in high rates during play behavior, mating, as well as in anticipation of rewarding events. The neurochemistry of 22-kHz and 50-kHz calls closely matches that of negative and positive emotional systems in humans, respectively. The aim of this study was to replicate and further evaluate selective breeding for 50-kHz vocalization, in preparation for the analysis of the genetic underpinnings of the 50-kHz ultrasonic vocalization (USV). Isolate housed adolescent rats (23-26 days old) received experimenter administered tactile stimulation (dubbed "tickling"), which mimicked the rat rough-and-tumble play behavior. This stimulation has previously been shown to elicit high levels of 50-kHz USVs and to be highly rewarding in isolate-housed animals. Each tickling session consisted of 4 cycles of 15 seconds stimulation followed by 15 seconds no stimulation for a total of 2 min, and was repeated once per day across 4 successive days. Rats were then selected for either High or Low levels of sonographically verified 50-kHz USVs in response to the stimulation, and a randomly selected line served as a control (Random group). Animals emitted both 22-kHz and 50-kHz types of calls. After 5 generations, animals in the High Line exhibited significantly more 50-kHz and fewer 22-kHz USVs than animals in the Low Line. Animals selected for low levels of 50-kHz calls showed marginally more 22-kHz USVs then randomly selected animals but did not differ in the rate of 50-kHz calls. These results extend our previous findings that laboratory rats could be bred for differential rates of sonographically verified 50-kHz USVs.
Collapse
Affiliation(s)
- Jeffrey Burgdorf
- J.P. Scott Center for Neuroscience, Mind and Behavior Department of Psychology, Bowling Green State University, Bowling Green, OH 43403, USA
| | | | | | | | | |
Collapse
|
11
|
Ferguson SA, Cada AM. Spatial learning/memory and social and nonsocial behaviors in the Spontaneously Hypertensive, Wistar–Kyoto and Sprague–Dawley rat strains. Pharmacol Biochem Behav 2004; 77:583-94. [PMID: 15006470 DOI: 10.1016/j.pbb.2003.12.014] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2003] [Revised: 12/15/2003] [Accepted: 12/22/2003] [Indexed: 10/26/2022]
Abstract
The Spontaneously Hypertensive rat (SHR) is often described as less behaviorally reactive than its normotensive strain, the Wistar-Kyoto (WKY), although results are somewhat inconsistent across studies. In part, this may be due to the lack of a definitive characterization of "reactivity." Still, results from identical behavioral tests of SHR and WKY across studies are sometimes conflicting. Further, few comparisons with other rodent strains are available and these might provide guidance in outlining the meaning of reactivity. Here, social and nonsocial behaviors and spatial learning and memory were measured in male and female SHR, WKY, and Sprague-Dawley (SD) rats. Systolic blood pressure measurements at adulthood confirmed hypertension in the SHR. Juvenile play behavior indicated that SHRs were more sensitive to the strain of their play partner than were the WKY or SD, playing less with different strain partners than with same strain partners. However, adult dominance behavior (restricted access in a water competition test) indicated no strain differences. The SHR appeared to exhibit attenuated acoustic startle relative to the WKY and SD and their prepulse inhibition was substantially less at higher prepulse decibel intensities; however, this decreased prepulse inhibition was not the result of decreased startle during the test. Anxiety-related behavior in the elevated plus maze was most prominent in the SD strain, possibly as a result of poorer motor coordination as measured by rotarod performance. Elevated plus maze behavior as well as motor coordination did not differ between the SHR and WKY strains. Performance in the NCTR complex maze and the Morris water maze was significantly better in the SHR. These results do not support hypotheses of decreased behavioral reactivity in the SHR strain. Rather, they suggest complex interactions between social and nonsocial environments and the behavioral capabilities and requirements of the rat strain.
Collapse
Affiliation(s)
- Sherry A Ferguson
- Division of Neurotoxicology, National Center for Toxicological Research/FDA, HFT-132, 3900 NCTR Road, Jefferson, AR 72079, USA.
| | | |
Collapse
|
12
|
Ferguson SA, Cada AM. A longitudinal study of short- and long-term activity levels in male and female spontaneously hypertensive, Wistar-Kyoto, and Sprague-Dawley rats. Behav Neurosci 2003; 117:271-82. [PMID: 12708524 DOI: 10.1037/0735-7044.117.2.271] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The pattern of locomotor activity across development was assessed in male and female spontaneously hypertensive (SHR), Wistar-Kyoto (WKY), and Sprague-Dawley (SD) rats. Open field activity did not indicate hyperactivity in the SHR. Instead, the SD strain was generally more active. Strains and sexes did not differ in open-field locomotor response to drug challenges. When short-term (10-12 min) activity in different apparatuses was compared, the SD were most active in the open field, the SHR in the residential figure-eight maze, and the WKY in the running wheel. Long-term tests indicated hyperactivity in the SHR in the residential figure-eight maze and hypoactivity in the SD in the running wheels. Until such strain differences in activity are thoroughly defined, the use of the SHR as a model of attention-deficit/ hyperactivity disorder is limited.
Collapse
Affiliation(s)
- Sherry A Ferguson
- Division of Neurotoxicology, Jefferson, National Center for Toxicological Research, U.S. Food and Drug Administration, Arkansas 72079, USA.
| | | |
Collapse
|
13
|
Abstract
The way genetic and/or environmental factors influence psychiatric disorders is an enduring question in the field of human psychiatric diseases. Anxiety-related disorders provide a relevant example of how such an interaction is involved in the aetiology of a psychiatric disease. In this paper we review the literature on that subject, reporting data derived from human and rodent studies. We present in a critical way the animal models used in the studies aimed at investigating the genetic basis of anxiety, including inbred mice, selected lines, multiple marker strains, or knockout mice and review data reporting environmental components influencing anxiety-related behaviours. We conclude that anxiety is a complex behaviour, underlined not only by genetic or environmental factors but also by multiple interactions between these two factors.
Collapse
Affiliation(s)
- Yan Clément
- Université Reims Champagne-Ardenne, Taittinger, Reims Cedex, France
| | | | | |
Collapse
|
14
|
Knapp DJ, Sim-Selley LJ, Breese GR, Overstreet DH. Selective breeding of 5-HT(1A) receptor-mediated responses: application to emotion and receptor action. Pharmacol Biochem Behav 2000; 67:701-8. [PMID: 11166060 DOI: 10.1016/s0091-3057(00)00415-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rat lines that were selectively bred for high (high DPAT-sensitive, HDS) or low (low DPAT-sensitive, LDS) hypothermic responses to the specific 5-HT(1A) receptor agonist, 8-hydroxy-di-n-propylaminotetralin (8-OH-DPAT), differ in receptor binding and certain behaviors related to anxiety and depression. After reviewing this literature, the present communication summarizes new experiments designed to clarify and extend the nature of the pharmacological and biochemical differences between the lines. A challenge with the 5-HT(2) receptor agonist, DOI, produced similar degrees of head shakes and skin crawls in the HDS and LDS rats, suggesting similar sensitivity of 5-HT(2A) and 5-HT(2C) receptors. In contrast, DOI-induced flat body posture (FBP), which has been linked to 5-HT(1A) receptor stimulation, was observed more readily in the HDS rats. The HDS and LDS rats exhibited similar degrees of increase in 8-OH-DPAT-stimulated [35S]GTPgammaS binding in several brain regions. This result suggests that the dramatic differences in hypothermia in HDS and LDS rats cannot be related to 5-HT(1A) receptor-mediated action on G proteins. Overall, these findings indicate that the selective breeding for 5-HT(1A)-mediated hypothermia has been fairly selective, and that differences in emotionally relevant behaviors between these two rat lines can strongly be associated with an unidentified component of the 5-HT(1A) receptor signaling pathway.
Collapse
Affiliation(s)
- D J Knapp
- Bowles Center for Alcohol Studies and Department of Psychiatry, CB 7178, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
| | | | | | | |
Collapse
|
15
|
Marissal-Arvy N, Mormède P, Sarrieau A. Strain differences in corticosteroid receptor efficiencies and regulation in Brown Norway and Fischer 344 rats. J Neuroendocrinol 1999; 11:267-73. [PMID: 10223280 DOI: 10.1046/j.1365-2826.1999.00323.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During the dark phase of the diurnal cycle, and during recovery from restraint stress, Brown Norway (BN) rats secrete less corticosterone than Fischer 344 (F344) rats. These strains also display different levels of corticosteroid receptors in the hippocampus, and of plasma transcortin. Because corticosteroid receptors, plasma transcortin and corticosterone secretion are mutually regulated, we examined brain and pituitary mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) expression and some of the parameters modulated by these receptors (i.e. body and thymus weight, fluid intake, plasma transcortin) in BN and F344 rat strains, by comparing the effects of either hormone deprivation by long-term (21 days) adrenalectomy (ADX), or chronic elevation of corticosterone given in drinking fluid to ADX rats. In BN rats, body weight gain and fluid intake were insensitive to corticosterone deprivation, suggesting that MR-related mechanisms are constitutively active in this strain. Body weight (b.w.) gain, plasma transcortin and thymus weight were reduced to a greater extent by chronic corticosterone in BN rats than in F344 rats, possibly as a consequence of higher free, active fraction of plasma corticosterone due to lower plasma transcortin concentrations and/or a greater efficiency of GR-related mechanisms in BN rats. F344 rats displayed twofold higher brain and pituitary MR levels than BN rats, whereas tissue-and strain-specific regulations were observed for GR levels. The differences in MR levels observed between BN and F344 strains cannot completely explain the differences in corticosterone actions, suggesting that strain differences in response to ADX or corticosterone treatment result from variable receptor efficiencies.
Collapse
Affiliation(s)
- N Marissal-Arvy
- Neurogénétique et Stress, INSERM U 471, INRA, Université de Bordeaux 2, Institut François Magendie de Neurosciences, France.
| | | | | |
Collapse
|
16
|
Sarrieau A, Chaouloff F, Lemaire V, Mormède P. Comparison of the neuroendocrine responses to stress in outbred, inbred and F1 hybrid rats. Life Sci 1998; 63:87-96. [PMID: 9674942 DOI: 10.1016/s0024-3205(98)00243-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In order to study the genetic factors involved in the neuroendocrine responses to stress, we have compared the intensity of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system activation following a 60 minute-restraint stress or after a 10 minute-exposure to a novel environment in three rat strains : outbred Wistar, inbred Brown Norway and Fischer 344, and F1 hybrid Brown Norway x Fischer 344 rats. The basal activity of the HPA axis did not differ between the four groups of rats whereas Brown Norway rats had the lowest release of corticosterone following restraint stress. Although differences in plasma adrenocorticotropic hormone failed to reach significance after exposure to a novel environment, the lowest level of corticosterone was found in Brown Norway rats. This lower release of corticosterone in Brown Norway rats has probably an adrenal origin as suggested by the ratios of corticosterone to ACTH levels following exposure to a novel environment: 632 +/- 222, 200 +/- 45, 636 +/- 89, 258 +/- 65 in Wistar, Brown Norway, Fischer 344 and F1 hybrids, respectively. This trait was dominant over the "adrenal responsive" phenotype of the Fischer 344 rat strain. In response to novelty, the lowest levels of prolactin and renin activity were found in plasma of Brown Norway and Wistar rats and the highest in Fischer 344 and F1 hybrid Brown Norway x Fischer 344 rats, the "high response" phenotype of the Fischer 344 strain being dominant. No strain-related difference was found in plasma glucose and either adrenal tyrosine hydroxylase or phenylethanolamine N-methyl transferase activity. Taken together, these data suggest that 1) genetic factors might contribute to the interindividual differences in neuroendocrine responses to stress and 2) subsets of these responses are controlled by specific genetic factors.
Collapse
Affiliation(s)
- A Sarrieau
- Neurogénétique et Stress, INSERM U 471-INRA-Université de Bordeaux II, Institut François Magendie de Neurosciences, France
| | | | | | | |
Collapse
|
17
|
Sarrieau A, Mormède P. Hypothalamic-pituitary-adrenal axis activity in the inbred Brown Norway and Fischer 344 rat strains. Life Sci 1998; 62:1417-25. [PMID: 9585169 DOI: 10.1016/s0024-3205(98)00080-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have examined the basal and the stress-induced secretion of corticosterone in relation to the expression of adrenal steroid receptors in the pituitary, hypothalamus and hippocampus of the inbred Brown Norway and Fischer 344 rat strains. Our data indicated that plasma transcortin and integrated plasma corticosterone levels were significantly higher in Fischer 344 compared to Brown Norway rats. Fischer 344 hypersecrete corticosterone during the dark phase of the diurnal cycle and during the phase of recovery following a 20 min period of restraint stress compared to Brown Norway rats. This hypersecretion of corticosterone was negatively correlated with the size of the adrenal gland but might be related to the higher density of mineralocorticoid receptors in the hippocampus of Fischer 344 rats.
Collapse
Affiliation(s)
- A Sarrieau
- Génétique du Stress et Neurobiologie de l'Adaptation, INSERM-INRA-Université de Bordeaux II, Institut François Magendie de Neurosciences, France
| | | |
Collapse
|
18
|
Abstract
The use of behavioural tests aiming to assess the psychological components of stress in animals has led to divergent and sometimes arbitrary interpretations of animal behaviour. This paper presents a critical evaluation of behavioural methods currently used to investigate stress and emotionality. One of its main goals is to demonstrate, through experimental evidence, that emotionality may no longer be seen as a unidimensional construct. Accordingly, following a discussion about concepts, we propose a multiple-testing approach, paralleled by factor analyses, as a tool to dissociate and study the different dimensions of emotionality. Within this multidimensional context, genetic studies (illustrated here by different rat models) are shown to be particularly useful to investigate the neurobiology of stress/emotionality. A genetic approach can be used (i) to broaden and dissect the variability of responses within and between populations and (ii) to search for the molecular bases (i.e. genes and gene products) which underlie such a variability.
Collapse
Affiliation(s)
- A Ramos
- Génétique du Stress CJF 94-05 INSERM--Institut François Magendie, Brodeaux, France
| | | |
Collapse
|
19
|
Knapp DJ, Overstreet DH, Crews FT. Brain 5-HT1A receptor autoradiography and hypothermic responses in rats bred for differences in 8-OH-DPAT sensitivity. Brain Res 1998; 782:1-10. [PMID: 9519243 DOI: 10.1016/s0006-8993(97)01127-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Three rat lines were selectively bred for high (HDS), random (RDS), or low (LDS) hypothermic responses to the specific 5-HT1A receptor agonist 8-OH-DPAT. Forty-five minutes after 8-OH-DPAT administration (0.5 mg/kg), body temperatures dropped 3-5 degrees C in HDS rats, yet this dose produced only about 1.2 degrees C and 0.7 degree C drops in RDS and LDS rats, respectively. To investigate the relationship of body temperature of 5-HT1A receptor binding sites, autoradiographic analyses of [3H]8-OH-DPAT binding to 5-HT1A receptors in brains of these rats were conducted. Significant differences in binding were found in specific limbic cortical projection sites, with the HDS line having the greatest density of sites. Body temperature responses correlated significantly with [3H]8-OH-DPAT receptor binding in only a few areas of frontal cortex. Binding in many other brain regions, including the anterior and posterior hypothalami (regions long associated with body temperature regulation) and the raphe showed no significant differences among the lines. [3H]Ketanserin binding to cortical 5-HT2 receptors did not differ among the lines, except in the cingulate and superficial frontal cortices where HDS exhibited higher binding. These data suggest that differences in 5-HT1A receptor number may contribute to the exaggerated hypothermic response to 8-OH-DPAT in HDS rats. These studies also suggest that genetic regulation of receptor density may be brain region specific which should encourage future studies of the mechanisms of 5-HT1A receptor activity in brain and the action of drugs affecting this receptor.
Collapse
Affiliation(s)
- D J Knapp
- Skipper Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA.
| | | | | |
Collapse
|
20
|
Knapp R, Moore MC. Male morphs in tree lizards have different testosterone responses to elevated levels of corticosterone. Gen Comp Endocrinol 1997; 107:273-9. [PMID: 9245535 DOI: 10.1006/gcen.1997.6923] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Changes in circulating glucocorticoid and androgen levels mediate agonistic behaviors in many vertebrates. Individual variation in the magnitude of the glucocorticoid response to stressful stimuli, the negative effects of elevated glucocorticoid levels on androgen levels, or both could mediate individual differences in subsequent agonistic behavior. In a series of previous studies, we found that both alternative male reproductive morphs in the tree lizard, Urosaurus ornatus, can exhibit elevated levels of plasma corticosterone following male-male encounters, but that the territorial morph appears less likely to exhibit coincident decreases in plasma testosterone. Two studies tested the hypothesis that the two morphs differ in the degree to which testosterone levels are influenced by elevated corticosterone levels. In the first study, physically restraining males elicited endogenous elevations of circulating corticosterone levels. Testosterone levels were significantly negatively correlated with corticosterone levels in the nonterritorial morph, but there was no correlation between levels of the two steroids in territorial males. In the second study, corticosterone levels were artificially elevated in free-living male tree lizards using a noninvasive dermal patch. This exogenous elevation of corticosterone significantly depressed testosterone levels in both morphs, but it produced a significantly greater depression in the nonterritorial morph. Nonterritorial males appear to be more sensitive than territorial males to the testosterone-suppressing effects of elevated circulating levels of corticosterone. This difference between the morphs in the effects of a stress hormone on the reproductive axis may be a fundamental part of the mechanism (1) underlying behavioral tactic switching within the nonterritorial morph or (2) contributing to behavioral differences between the morphs.
Collapse
Affiliation(s)
- R Knapp
- Department of Zoology, Arizona State University, Tempe, Arizona 85287-1501, USA
| | | |
Collapse
|
21
|
Clément Y, Proeschel MF, Bondoux D, Girard F, Launay JM, Chapouthier G. Genetic factors regulate processes related to anxiety in mice. Brain Res 1997; 752:127-35. [PMID: 9106448 DOI: 10.1016/s0006-8993(96)01467-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The propensity for anxiety-related behavior has been studied by comparing two highly inbred strains of mice, ABP/Le and C57BL/6ByJ, in two behavioral procedures, open-field and light-dark preference. Their Mendelian F2 population allowed us to evaluate the putative involvement of four easily identifiable loci in anxiogenic processes. In fact, chromosomal regions containing the brown, pink-eyed dilution and short-ear loci on the 4th, 7th and 9th chromosomes respectively are associated with anxiety-related behavior patterns. In addition, binding of [3H]flumazenil to brain GABA(A) receptors was measured as a biochemical index that may be associated with observed behavior patterns.
Collapse
Affiliation(s)
- Y Clément
- U.R.A. C.N.R.S. 1957, Groupe hospitalier Pitié-Salpêtrière, Paris, France
| | | | | | | | | | | |
Collapse
|
22
|
Haney M, Castanon N, Cador M, Le Moal M, Mormède P. Cocaine sensitivity in Roman High and Low Avoidance rats is modulated by sex and gonadal hormone status. Brain Res 1994; 645:179-85. [PMID: 8062080 DOI: 10.1016/0006-8993(94)91651-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Repeated exposure to stressful stimuli or psychostimulants increases sensitivity to the motoric effects of these drugs, i.e. behavioral sensitization. The objective of the present experiment was to determine the interaction between factors that modulate psychostimulant sensitivity, i.e. sex and circulating gonadal hormone levels, in rats with a genetically distinct locomotor response to novelty: Roman Low Avoidance rats (RLA) freeze while Roman High Avoidance rats (RHA) remain motorically active. Ninety-six male and female RHA and RLA rats were gonadectomized (GDX) just after weaning or as adults, or left gonadally intact. Each rat received a total of 9 injections of cocaine hydrochloride (10 mg/kg, IP), at 3-4 day intervals for 5 weeks. Locomotor activity was measured after each injection, and stereotypes were rated 1 x/week. Open field behavior (10 min) and plasma corticosterone were measured 2 weeks after the final injection. Overall, the RHA line was more sensitive to (1) cocaine's stereotypic effects, and (2) the influence of ovarian hormones on the cocaine's acute and sensitizing effects on locomotor activity. Therefore, genetic background not only determines cocaine sensitivity, but also the influence of gonadal hormones on locomotor activity. These interactions are relevant when considering the genetic contribution to abuse liability.
Collapse
Affiliation(s)
- M Haney
- Laboratoire de Psychobiologie des Comportements, Adaptatifs, INSERM U.259, Université de Bordeaux II, France
| | | | | | | | | |
Collapse
|
23
|
Mihic SJ, Van Berckel BN, O'Dowd BF, Nguyen T, Wu PH. Effects of sedatives on GABA-mediated chloride flux into cerebral cortical microsacs prepared from emotional and non-emotional mice. Eur J Pharmacol 1992; 218:283-6. [PMID: 1330599 DOI: 10.1016/0014-2999(92)90180-c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Some strains of rats and mice express increased momentary fear or emotionality when exposed to a novel environment. Previous studies have found significantly fewer diazepam binding sites in the brains of Balb/cJ mice compared to C57BL and AKR/J mice and this has been suggested to contribute to the increased emotionally of the 'nervous' Balb strain. The influx of 36Cl into cerebral cortical microsacs was used to functionally assess the effects of GABA, diazepam and pentobarbital in the Balb mice compared to nonemotional animals (C57 and ICR mice). Slight differences in the ability of GABA to increase chloride influx were found among the three strains. Pentobarbital potentiation of GABA-mediated chloride flux was slightly higher in the ICR mice compared to Balb and C57. Diazepam potentiation of the effects of GABA, however, was significantly decreased in the Balb mice, strengthening the hypothesis that the benzodiazepine receptor is involved in mediating animal emotionality.
Collapse
Affiliation(s)
- S J Mihic
- Department of Pharmacology, University of Toronto, Ont., Canada
| | | | | | | | | |
Collapse
|
24
|
Abstract
While the secretion of glucocorticoids by the adrenal gland is essential for survival of various stressors, glucocorticoid excess can be pathogenic. This two-edged quality to glucocorticoid action makes it of interest whether glucocorticoid concentrations change with age. Numerous studies have examined this in the rat but have failed to reach consensus. The present report analyzes this literature and concludes that the lack of consensus cannot be attributed to strain or sex differences or differences in the point in the circadian cycle at which rats were studied. Instead, it appears that a critical variable is how truly "basal" (i.e., unstressed) basal samples were; in studies in which basal glucocorticoid concentrations in young control subjects were in a range reflecting unstressed basal conditions, there is a robust increase in hormone concentrations with age. In contrast, the bulk of studies reporting no increase with age were those in which young subjects had elevated basal glucocorticoid concentrations (perhaps reflecting the method and speed of obtaining the blood sample, the social conditions of the rat housing, and/or the recency with which there was a disturbance in the animal room). Thus, it appears that once this source of variability is recognized and factored out, there is a considerable increase in basal glucocorticoid concentrations in aged rats.
Collapse
Affiliation(s)
- R M Sapolsky
- Department of Biological Sciences, Stanford University, CA 94305-5020
| |
Collapse
|
25
|
Everill B, Brain P, Rustana A, Mos J, Olivier B. Ethoexperimental analysis of the impact of chlordiazepoxide (CDP) on social interactions in three strains of mice. Behav Processes 1991; 25:55-67. [DOI: 10.1016/0376-6357(91)90045-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/1991] [Indexed: 12/11/2022]
|
26
|
Gentsch C, Lichtsteiner M, Feer H. Genetic and environmental influences on reactive and spontaneous locomotor activities in rats. EXPERIENTIA 1991; 47:998-1008. [PMID: 1936209 DOI: 10.1007/bf01923335] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Paired groups of rats (derived from divergent, selective breeding or living in divergent environmental conditions) were compared with regard to locomotor activities. Intrapair differences were found to vary non-systematically, depending upon whether the rats were initially exposed to a test-environment with or without a slight environmental modification (reactive activities), or were allowed to habituate extensively to the environment (spontaneous activity). Since the behavioral patterns were found to represent distinct entities, this pointed to the necessity of differentiating clearly between spontaneous and reactive activities and indicated, once again, that both genetic and environmental influences are important in these behaviors and must be taken into account. Accepting and controlling for these variables makes it possible to use the factor of individual differences in laboratory animal behavior to advantage.
Collapse
Affiliation(s)
- C Gentsch
- Psychiatrische Universitätsklinik Basel, Switzerland
| | | | | |
Collapse
|
27
|
Cools AR, Brachten R, Heeren D, Willemen A, Ellenbroek B. Search after neurobiological profile of individual-specific features of Wistar rats. Brain Res Bull 1990; 24:49-69. [PMID: 2310946 DOI: 10.1016/0361-9230(90)90288-b] [Citation(s) in RCA: 204] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The first part of this study demonstrates that the bimodal shape of variation in "fleeing" and "nonfleeing" or "freezing" rats of an outbred strain of Wistar rats forms part of an overall biomodal variation in behavioural responses to injections of agents, which selectively alter, or reflect, the noradrenergic or dopaminergic activity in the ventral striatum, and dopaminergic activity in the dorsal striatum, the GABA-ergic activity in the substantia nigra, pars reticulata, and the GABA-ergic activity in the deeper layers of the superior colliculus. It is concluded that the "fleeing" and "nonfleeing" rats, each of them marked by their own trans-situational consistency in pharmacological and behavioural responses, represent the two fundamentally different types of individuals which normally exist in unselected populations of rodents. The second part of this study demonstrates that the pharmacogenetic selection of apomorphine-susceptible (APO-SUS) and apomorphine-unsusceptible (APO-UNSUS) rats, i.e., one individual-specific feature of the overall bimodal variation for pharmacological responses in our outbred strain of rats, is a valid tool to disperse the above-mentioned individual-specific features as far as possible. First, these lines allowed us to prove that the overall bimodal shape of variation in pharmacological and behavioral responses of individual outbred rats is in part genetically determined. Second, these lines allowed us to prove that a bimodal variation in neurochemical features of the circuitry, in which the ventral striatum is embedded, underlies the overall bimodal variation in pharmacological and behavioural responses. Third, these lines allowed us to demonstrate that a fundamental difference in organizing behaviour with the help of external and internal information has to be considered as a common factor giving rise to the individual differentiation found in the present study. Given the notion that this individual differentiation appears to be valid across lines, substrains and strains of rats, the present study lays the foundation for understanding at least a part of the physiological basis underlying differences between the two fundamentally different types of individuals existing in normal populations of rodents.
Collapse
Affiliation(s)
- A R Cools
- Psychoneuropharmacological Research-Unit, University of Nijmegen, The Netherlands
| | | | | | | | | |
Collapse
|
28
|
Driscoll P. Genetic models in brain and behavior research, Part II. Progress report. EXPERIENTIA 1989; 45:787-8. [PMID: 2776857 DOI: 10.1007/bf01954053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- P Driscoll
- Laboratorium für vergleichende Physiologie und Verhaltensbiologie, ETH-Zentrum, Zürich, Switzerland
| |
Collapse
|