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Porras-García E, Mas-Nieto M, Delgado-García JM, Domínguez-Del-Toro E. Noradrenergic projections regulate the acquisition of classically conditioned eyelid responses in wild-type and are impaired in kreisler mice. Sci Rep 2023; 13:11458. [PMID: 37454229 PMCID: PMC10349844 DOI: 10.1038/s41598-023-38278-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
During embryonic development, heterozygous mutant kreisler mice undergo ectopic expression of the Hoxa3 gene in the rostral hindbrain, affecting the opioid and noradrenergic systems. In this model, we have investigated behavioral and cognitive processes in their adulthood. We confirmed that pontine and locus coeruleus neuronal projections are impaired, by using startle and pain tests and by analyzing immunohistochemical localization of tyrosine hydroxylase. Our results showed that, even if kreisler mice are able to generate eyelid reflex responses, there are differences with wild-types in the first component of the response (R1), modulated by the noradrenergic system. The acquisition of conditioned motor responses is impaired in kreisler mice when using the trace but not the delay paradigm, suggesting a functional impairment in the hippocampus, subsequently confirmed by reduced quantification of alpha2a receptor mRNA expression in this area but not in the cerebellum. Moreover, we demonstrate the involvement of adrenergic projection in eyelid classical conditioning, as clonidine prevents the appearance of eyelid conditioned responses in wild-type mice. In addition, hippocampal motor learning ability was restored in kreisler mice by administration of adrenergic antagonist drugs, and a synergistic effect was observed following simultaneous administration of idazoxan and naloxone.
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Affiliation(s)
- Elena Porras-García
- Division of Neurosciences, University Pablo de Olavide, Ctra. de Utrera, Km. 1, 41013, Sevilla, Spain
| | - Magdalena Mas-Nieto
- Division of Neurosciences, University Pablo de Olavide, Ctra. de Utrera, Km. 1, 41013, Sevilla, Spain
| | - José María Delgado-García
- Division of Neurosciences, University Pablo de Olavide, Ctra. de Utrera, Km. 1, 41013, Sevilla, Spain
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Sommer JL, Low AM, Jepsen JRM, Fagerlund B, Vangkilde S, Habekost T, Glenthøj B, Oranje B. Effects of methylphenidate on sensory and sensorimotor gating of initially psychostimulant-naïve adult ADHD patients. Eur Neuropsychopharmacol 2021; 46:83-92. [PMID: 33663902 DOI: 10.1016/j.euroneuro.2021.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 01/15/2021] [Accepted: 02/09/2021] [Indexed: 11/16/2022]
Abstract
Deficient information processing in ADHD theoretically results in sensory overload, which in turn may underlie its symptoms. If this sensory overload is caused by deficient filtering of environmental stimuli, then one would expect finding deficits in P50 gating and prepulse inhibition of the startle reflex (PPI). Previous reports on these measures in ADHD have shown inconsistent findings, which may have been caused by either medication use or comorbidity (e.g. ASD). The primary aim of this study was therefore to explore P50 suppression and PPI in adult, psychostimulant-naïve patients with ADHD without major comorbidity, and to examine the effects of 6 weeks treatment with methylphenidate (MPH) on these measures. A total of 42 initially psychostimulant-naive, adult ADHD patients without major comorbidity and 42 matched healthy controls, were assessed for their P50 gating, PPI, and habituation/sensitization abilities at baseline and after 6 weeks of treatment with methylphenidate. Although six weeks of treatment with MPH significantly reduced symptomatology as well as improved daily life functioning in our patients, it neither significantly affected PPI, P50 suppression nor sensitization, but habituation unexpectedly decreased. The absence of PPI and P50 suppression deficits in our patients in the psychostimulant-naïve state indicates no gating deficits. In turn, this suggests that the difficulties to inhibit distraction of attention by irrelevant stimuli that many patients with (adult) ADHD report, have a different origin than the theoretical causes of sensory overload frequently reported in studies on patients with schizophrenia.
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Affiliation(s)
- Julijana le Sommer
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Mental Health Centre Glostrup, Glostrup, Denmark; Department of Psychology, University of Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Faculty of Health and Medical Sciences, Denmark
| | - Ann-Marie Low
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Mental Health Centre Glostrup, Glostrup, Denmark; Department of Psychology, University of Copenhagen, Denmark
| | - Jens Richardt Møllegaard Jepsen
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Mental Health Centre Glostrup, Glostrup, Denmark; Child and Adolescent Mental Health Center, Mental Health Services, Copenhagen, Denmark
| | - Birgitte Fagerlund
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Mental Health Centre Glostrup, Glostrup, Denmark
| | | | | | - Birte Glenthøj
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Mental Health Centre Glostrup, Glostrup, Denmark; Department of Clinical Medicine, University of Copenhagen, Faculty of Health and Medical Sciences, Denmark
| | - Bob Oranje
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Mental Health Centre Glostrup, Glostrup, Denmark; Department of Psychiatry, UMC-Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands.
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Toth M, Ziegler M, Sun P, Gresack J, Risbrough V. Impaired conditioned fear response and startle reactivity in epinephrine-deficient mice. Behav Pharmacol 2013; 24:1-9. [PMID: 23268986 DOI: 10.1097/FBP.0b013e32835cf408] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Norepinephrine and epinephrine signaling is thought to facilitate cognitive processes related to emotional events and heightened arousal; however, the specific role of epinephrine in these processes is less known. To investigate the selective impact of epinephrine on arousal and fear-related memory retrieval, mice unable to synthesize epinephrine (phenylethanolamine N-methyltransferase knockout, PNMT-KO) were tested for contextual and cued-fear conditioning. To assess the role of epinephrine in other cognitive and arousal-based behaviors these mice were also tested for acoustic startle, prepulse inhibition, novel object recognition, and open-field activity. Our results show that compared with wild-type mice, PNMT-KO mice showed reduced contextual fear but normal cued fear. Mice exhibited normal memory performance in the short-term version of the novel object recognition task, suggesting that PNMT mice exhibit more selective memory effects on highly emotional and/or long-term memories. Similarly, open-field activity was unaffected by epinephrine deficiency, suggesting that differences in freezing are not related to changes in overall anxiety or exploratory drive. Startle reactivity to acoustic pulses was reduced in PNMT-KO mice, whereas prepulse inhibition was increased. These findings provide further evidence for a selective role of epinephrine in contextual-fear learning and support its potential role in acoustic startle.
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Abstract
BACKGROUND Cognitive deficits form core features in schizophrenia. Several studies have shown improvements in prefrontal cognitive function by α 2 -agonists in schizophrenia. In the present study, it was investigated whether clonidine (an α 2 -adrenoceptor agonist) could normalize sensorimotor gating deficits in schizophrenia. METHODS In a double blind, placebo controlled, randomized, yet balanced, cross-over experiment, 20 male schizophrenia patients on stable medication were assessed in an auditory prepulse inhibition (PPI), sensitization, and habituation of the startle reflex paradigm on 5 occasions: once after oral administration of placebo and after a single dose of 25, 50, 75, and 150 µg of clonidine. Their results were compared with 20 age- and gender-matched healthy volunteers, who received no treatment. RESULTS In the placebo treatment, patients showed deficient PPI and sensitization, yet normal habituation compared with the controls. Except the highest dose, all dosages of clonidine significantly increased percentage PPI in the patients compared with placebo, to such levels that it no longer differed significantly from the healthy controls. However, none of the dosages increased sensitization or influenced habituation. CONCLUSIONS This is the first study to show that even a single low dose of clonidine added to the medical treatment of patients with schizophrenia who are clinically stable on their antipsychotic medication not only significantly ameliorates their PPI deficits, but also normalizes them. The results have a potentially high clinical relevance for the medical treatment of schizophrenia.
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Affiliation(s)
- Bob Oranje
- Center for Neuropsychiatric Schizophrenia Research (CNSR), Copenhagen University Hospital, Psychiatric Center Glostrup, Glostrup, Denmark.
| | - Birte Y. Glenthøj
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Copenhagen University Hospital, Psychiatric Center GlostrupGlostrup, Denmark
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,Faculty of Health Sciences, Department of Neurology, Psychiatry, and Sensory Sciences, University of CopenhagenCopenhagen, Denmark
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Grashow R, Miller MW, McKinney A, Nie LH, Sparrow D, Hu H, Weisskopf MG. Lead exposure and fear-potentiated startle in the VA Normative Aging Study: a pilot study of a novel physiological approach to investigating neurotoxicant effects. Neurotoxicol Teratol 2013; 38:21-8. [PMID: 23603705 DOI: 10.1016/j.ntt.2013.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Physiologically-based indicators of neural plasticity in humans could provide mechanistic insights into toxicant actions on learning in the brain, and perhaps prove more objective and sensitive measures of such effects than other methods. OBJECTIVES We explored the association between lead exposure and classical conditioning of the acoustic startle reflex (ASR)-a simple form of associative learning in the brain-in a population of elderly men. Fifty-one men from the VA Normative Aging Study with cumulative bone lead exposure measurements made with K-X-Ray-Fluorescence participated in a fear-conditioning protocol. RESULTS The mean age of the men was 75.5years (standard deviation [sd]=5.9) and mean patella lead concentration was 22.7μg/g bone (sd=15.9). Baseline ASR eyeblink response decreased with age, but was not associated with subsequent conditioning. Among 37 men with valid responses at the end of the protocol, higher patella lead was associated with decreased awareness of the conditioning contingency (declarative learning; adjusted odds ratio [OR] per 20μg/g patella lead=0.91, 95% confidence interval [CI]: 0.84, 0.99, p=0.03). Eyeblink conditioning (non-declarative learning) was 0.44sd less (95% CI: -0.91, 0.02; p=0.06) per 20μg/g patella lead after adjustment. Each result was stronger when correcting for the interval between lead measurement and startle testing (awareness: OR=0.88, 95% CI: 0.78, 0.99, p=0.04; conditioning: -0.79sd less, 95% CI: -1.56, 0.03, p=0.04). CONCLUSIONS This initial exploration suggests that lead exposure interferes with specific neural mechanisms of learning and offers the possibility that the ASR may provide a new approach to physiologically explore the effects of neurotoxicant exposures on neural mechanisms of learning in humans with a paradigm that is directly comparable to animal models.
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Affiliation(s)
- Rachel Grashow
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
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Corr PJ, Kumari V. Effect of D-amphetamine on emotion-potentiated startle in healthy humans: implications for psychopathy and antisocial behaviour. Psychopharmacology (Berl) 2013; 225:373-9. [PMID: 22864946 DOI: 10.1007/s00213-012-2824-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 07/18/2012] [Indexed: 10/28/2022]
Abstract
RATIONALE An emerging literature associates increased dopaminergic neurotransmission with altered brain response to aversive stimuli in humans. The direction of the effect of dopamine on aversive motivation, however, remains unclear, with some studies reporting increased and others decreased amygdala activation to aversive stimuli following the administration of dopamine agonists. Potentiation of the startle response by aversive foreground stimuli provides an objective and directional measure of emotional reactivity and is considered useful as an index of the emotional effects of different drugs. OBJECTIVE We investigated the effects of two doses of D-amphetamine (5 and 10 mg), compared to placebo, for the first time to our knowledge, using the affect-startle paradigm. METHOD The study employed a between-subjects, double-blind design, with three conditions: 0 mg (placebo), and 5 and 10 mg D-amphetamine (initially n = 20/group; final sample: n = 18, placebo; n = 18, 5 mg; n = 16, 10 mg). After drug/placebo administration, startle responses (eyeblinks) to intermittent noise probes were measured during viewing of pleasant, neutral and unpleasant images. Participants' general and specific impulsivity and fear-related personality traits were also assessed. RESULTS The three groups were comparable on personality traits. Only the placebo group showed significant startle potentiation by unpleasant, relative to neutral, images; this effect was absent in both 5- and 10-mg D-amphetamine groups (i.e. the same effect of D-amphetamine observed at different doses in different people). CONCLUSIONS Our findings demonstrate a reduced aversive emotional response under D-amphetamine and may help to account for the known link between the use of psychostimulant drugs and antisocial behaviour.
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Affiliation(s)
- Philip J Corr
- School of Psychology, University of East Anglia, Norwich, UK
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Abstract
The locus coeruleus (LC) is activated by noxious stimuli, and this activation leads to inhibition of perceived pain. As two physiological reflexes, the acoustic startle reflex and the pupillary light reflex, are sensitive to noxious stimuli, this review considers evidence that this sensitivity, at least to some extent, is mediated by the LC. The acoustic startle reflex, contraction of a large body of skeletal muscles in response to a sudden loud acoustic stimulus, can be enhanced by both directly ("sensitization") and indirectly ("fear conditioning") applied noxious stimuli. Fear-conditioning involves the association of a noxious (unconditioned) stimulus with a neutral (conditioned) stimulus (e.g., light), leading to the ability of the conditioned stimulus to evoke the "pain response". The enhancement of the startle response by conditioned fear ("fear-potentiated startle") involves the activation of the amygdala. The LC may also be involved in both sensitization and fear potentiation: pain signals activate the LC both directly and indirectly via the amygdala, which results in enhanced motoneurone activity, leading to an enhanced muscular response. Pupil diameter is under dual sympathetic/parasympathetic control, the sympathetic (noradrenergic) output dilating, and the parasympathetic (cholinergic) output constricting the pupil. The light reflex (constriction of the pupil in response to a light stimulus) operates via the parasympathetic output. The LC exerts a dual influence on pupillary control: it contributes to the sympathetic outflow and attenuates the parasympathetic output by inhibiting the Edinger-Westphal nucleus, the preganglionic cholinergic nucleus in the light reflex pathway. Noxious stimulation results in pupil dilation ("reflex dilation"), without any change in the light reflex response, consistent with sympathetic activation via the LC. Conditioned fear, on the other hand, results in the attenuation of the light reflex response ("fear-inhibited light reflex"), consistent with the inhibition of the parasympathetic light reflex via the LC. It is suggested that directly applied pain and fear-conditioning may affect different populations of autonomic neurones in the LC, directly applied pain activating sympathetic and fear-conditioning parasympathetic premotor neurones.
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Affiliation(s)
- Elemer Szabadi
- Psychopharmacology Section, Division of Psychiatry, University of NottinghamNottingham, UK
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Oranje B, Wienberg M, Glenthoj BY. A single high dose of escitalopram disrupts sensory gating and habituation, but not sensorimotor gating in healthy volunteers. Psychiatry Res 2011; 186:431-6. [PMID: 20971512 DOI: 10.1016/j.psychres.2010.09.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 09/27/2010] [Accepted: 09/30/2010] [Indexed: 10/18/2022]
Abstract
Early mechanisms to limit the input of sensory information to higher brain areas are important for a healthy individual. In previous studies, we found that a low dose of 10mg escitalopram (SSRI) disrupts habituation, without affecting sensory and sensorimotor gating in healthy volunteers. In the current study a higher dose of 15 mg was used. The hypothesis was that this higher dose of escitalopram would not only disrupt habituation, but also sensory and sensorimotor gating. Twenty healthy male volunteers received either placebo or 15 mg escitalopram, after which they were tested in a P50 suppression, and a habituation and prepulse inhibition (PPI) of the startle reflex paradigm. Escitalopram significantly decreased P50 suppression and habituation, but had no effect on PPI. The results indicate that habituation and sensory gating are disrupted by increased serotonergic activity, while sensorimotor gating seems relatively insensitive to such a rise. Since the patients who are frequently treated with SSRIs (patients with schizophrenia and affective disorders) might already suffer from disrupted sensory gating and habituation, the current results call for caution in the determination of a proper dose.
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Affiliation(s)
- Bob Oranje
- Copenhagen University, University Psychiatric Center Glostrup, Denmark.
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Samuels ER, Szabadi E. Functional neuroanatomy of the noradrenergic locus coeruleus: its roles in the regulation of arousal and autonomic function part I: principles of functional organisation. Curr Neuropharmacol 2010; 6:235-53. [PMID: 19506723 PMCID: PMC2687936 DOI: 10.2174/157015908785777229] [Citation(s) in RCA: 462] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 02/25/2008] [Accepted: 06/06/2008] [Indexed: 01/09/2023] Open
Abstract
The locus coeruleus (LC) is the major noradrenergic nucleus of the brain, giving rise to fibres innervating extensive areas throughout the neuraxis. Recent advances in neuroscience have resulted in the unravelling of the neuronal circuits controlling a number of physiological functions in which the LC plays a central role. Two such functions are the regulation of arousal and autonomic activity, which are inseparably linked largely via the involvement of the LC. The LC is a major wakefulness-promoting nucleus, resulting from dense excitatory projections to the majority of the cerebral cortex, cholinergic neurones of the basal forebrain, cortically-projecting neurones of the thalamus, serotoninergic neurones of the dorsal raphe and cholinergic neurones of the pedunculopontine and laterodorsal tegmental nucleus, and substantial inhibitory projections to sleep-promoting GABAergic neurones of the basal forebrain and ventrolateral preoptic area. Activation of the LC thus results in the enhancement of alertness through the innervation of these varied nuclei. The importance of the LC in controlling autonomic function results from both direct projections to the spinal cord and projections to autonomic nuclei including the dorsal motor nucleus of the vagus, the nucleus ambiguus, the rostroventrolateral medulla, the Edinger-Westphal nucleus, the caudal raphe, the salivatory nuclei, the paraventricular nucleus, and the amygdala. LC activation produces an increase in sympathetic activity and a decrease in parasympathetic activity via these projections. Alterations in LC activity therefore result in complex patterns of neuronal activity throughout the brain, observed as changes in measures of arousal and autonomic function.
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Affiliation(s)
- E R Samuels
- Psychopharmacology Section, University of Nottingham, Division of Psychiatry, Queen's Medical Centre, Nottingham, NG7 2UH, UK
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Giakoumaki SG, Bitsios P, Frangou S, Roussos P, Aasen I, Galea A, Kumari V. Low baseline startle and deficient affective startle modulation in remitted bipolar disorder patients and their unaffected siblings. Psychophysiology 2010; 47:659-68. [PMID: 20233338 DOI: 10.1111/j.1469-8986.2010.00977.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We examined whether startle abnormalities are present in bipolar disorder (BD) patients and their unaffected siblings. Twenty-one remitted patients with BD, 19 unaffected siblings, and 42 controls were presented with 18 pleasant, 18 unpleasant, and 18 neutral pictures. Acoustic probes (104 dB) were presented during 12 of 18 pictures in each affective category at 300, 3000, and 4500 ms after picture onset, so that there were 4 pictures per valence per probe onset type. Baseline startle was assessed during blank screens and was found reduced in patients and sibling groups. We found startle inhibition with the 300 probes and a linear increase in amplitude with valence with the late probes in controls; these effects were absent in patients and their siblings. Low startle and blunted startle reactivity may represent trait deficits in remitted BD patients and their relatives, possibly associated with attentional deficits and adaptive down-regulation of emotion.
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Affiliation(s)
- Stella G Giakoumaki
- Department of Psychiatry & Behavioral Sciences, Faculty of Medicine, University of Crete, Heraklion 71003, Greece
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Davis M, Walker DL, Miles L, Grillon C. Phasic vs sustained fear in rats and humans: role of the extended amygdala in fear vs anxiety. Neuropsychopharmacology 2010; 35:105-35. [PMID: 19693004 PMCID: PMC2795099 DOI: 10.1038/npp.2009.109] [Citation(s) in RCA: 1004] [Impact Index Per Article: 71.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/26/2009] [Accepted: 07/14/2009] [Indexed: 01/11/2023]
Abstract
Data will be reviewed using the acoustic startle reflex in rats and humans based on our attempts to operationally define fear vs anxiety. Although the symptoms of fear and anxiety are very similar, they also differ. Fear is a generally adaptive state of apprehension that begins rapidly and dissipates quickly once the threat is removed (phasic fear). Anxiety is elicited by less specific and less predictable threats, or by those that are physically or psychologically more distant. Thus, anxiety is a more long-lasting state of apprehension (sustained fear). Rodent studies suggest that phasic fear is mediated by the amygdala, which sends outputs to the hypothalamus and brainstem to produce symptoms of fear. Sustained fear is also mediated by the amygdala, which releases corticotropin-releasing factor, a stress hormone that acts on receptors in the bed nucleus of the stria terminalis (BNST), a part of the so-called 'extended amygdala.' The amygdala and BNST send outputs to the same hypothalamic and brainstem targets to produce phasic and sustained fear, respectively. In rats, sustained fear is more sensitive to anxiolytic drugs. In humans, symptoms of clinical anxiety are better detected in sustained rather than phasic fear paradigms.
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Affiliation(s)
- Michael Davis
- Department of Psychiatry, Yerkes National Primate Center, Emory University, and the Center for Behavioral Neuroscience, Atlanta, GA 30329, USA.
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Quevedo KM, Benning SD, Gunnar MR, Dahl RE. The onset of puberty: effects on the psychophysiology of defensive and appetitive motivation. Dev Psychopathol 2009; 21:27-45. [PMID: 19144221 DOI: 10.1017/S0954579409000030] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We examined puberty-specific effects on affect-related behavior and on the psychophysiology of defensive and appetitive motivation while controlling for age. Adolescents (N = 94, ages = 12 and 13 years) viewed 75 pictures (International Affective Picture System: pleasant, neutral, and aversive) while listening to auditory probes. Startle response and postauricular (PA) reflex were collected as measures of defensive and appetitive motivation, respectively. Pubertal status and measures of anxiety/stress reaction and sensation/thrill seeking were obtained. Mid-/late pubertal adolescents showed enhanced startle amplitude across all picture valences. A Puberty x Valence interaction revealed that mid-/late pubertal adolescents showed appetitive potentiation of the PA, whereas pre-/early pubertal adolescents showed no modulation of the PA reflex. Mid-/late pubertal adolescents also scored significantly higher on measures of sensation/thrill seeking than did their pre-/early pubertal peers and puberty moderated the association between psychophysiology and behavioral measures, suggesting that it plays a role in reorganizing defensive and appetitive motivational systems.
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Samuels ER, Hou RH, Langley RW, Szabadi E, Bradshaw CM. Modulation of the acoustic startle response by the level of arousal: comparison of clonidine and modafinil in healthy volunteers. Neuropsychopharmacology 2007; 32:2405-21. [PMID: 17342169 DOI: 10.1038/sj.npp.1301363] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A sudden loud sound evokes an electromyographic (EMG) response from the orbicularis oculi muscle in humans together with an auditory evoked potential (AEP) and an increase in skin conductance (SC). Startle responses are inhibited by weak prepulses (prepulse inhibition, (PPI)) and may also be modified by the level of alertness. We compared the sedative drug clonidine and the alerting drug modafinil on sound-evoked EMG, AEP, and SC responses, on the PPI of these responses and on level of arousal and autonomic functions. Sixteen healthy male volunteers participated in four weekly sessions (clonidine 0.2 mg, modafinil 400 mg, their combination, placebo) in a double-blind, cross-over, balanced design. Responses were evoked by sound pulses of 115 and 85 dB (PPI) for 40 ms and recorded conventionally. Level of alertness, autonomic functions (pupil diameter, blood pressure, heart rate, salivation, temperature) and the plasma levels of the hormones prolactin, thyroid-stimulating hormone and growth hormone were also measured. Data were analyzed with analysis of variance with multiple comparisons. Both prepulses and clonidine attenuated all three startle responses and modafinil antagonized clonidine's effects on the EMG and AEP responses. None of the drugs affected PPI. Clonidine showed sedative and sympatholytic effects, and modafinil showed alerting and sympathomimetic effects. In conclusion, startle responses were susceptible not only to PPI but also to the level of arousal.
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Affiliation(s)
- Ebony R Samuels
- Division of Psychiatry, Psychopharmacology Section, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, UK
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Scaife JC, Langley RW, Bradshaw CM, Szabadi E. Diazepam suppresses the acquisition but not the expression of 'fear-potentiation' of the acoustic startle response in man. J Psychopharmacol 2005; 19:347-56. [PMID: 15982989 DOI: 10.1177/0269881105053285] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sudden auditory stimuli elicit a short-latency muscular response (acoustic startle response) which is enhanced during presentation of a Pavlovian conditioned stimulus (CS) that has previously been paired with an aversive unconditioned stimulus (US) ('fear-potentiation'). In rodents, acute treatment with benzodiazepines blocks both the acquisition of fear-potentiation and the expression of fear-potentiation induced by prior exposure to CS/US pairing. We examined the effect of diazepam on the acquisition and expression of fear-potentiation of the acoustic startle response in man. Forty-six male volunteers (18-30 years) participated in two sessions separated by 7 days. In session 1, they were exposed to 20 2-s presentations of a light (CS), 50% of which terminated with an electric shock to the wrist (1.8 mA, 50 ms: US). Somatosensory potentials evoked by the US were recorded from the scalp at Cz, and skin conductance responses from electrodes taped to the second and fourth fingers. In session 2, the CS was presented 20 times without the US; a random 50% of CS presentations terminated with a sound pulse (40-ms 115-dB 1-kHz); an equal number of sound pulses was presented without the CS. Electromyographic responses of the orbicularis oculi muscle to the acoustic stimuli were recorded from electrodes placed on the lower eyelid, late-latency auditory evoked potentials were recorded at Cz, and skin conductance responses from electrodes taped to the second and fourth fingers. In each session, alertness was measured using visual analogue self-rating scales and critical flicker fusion frequency. Subjects received placebo or diazepam 10mg in the two sessions in a double-blind protocol: group 1 (n 12) placebo/placebo; group 2 (n 11) placebo/diazepam; group 3 (n 12) diazepam/placebo; group 4 (n 11) diazepam/diazepam. Diazepam reduced alertness as measured by visual-analogue self-rating scales and critical flicker fusion frequency. In session 1, diazepam reduced the amplitude of the somatosensory potentials and skin conductance responses evoked by the CS. In session 2, the acoustic startle response, the N1/P2 auditory evoked response and the skin conductance response evoked by the sound stimuli were enhanced in the presence of the CS. This fear-potentiation was attenuated in subjects who received diazepam in session 1, but was not affected by the treatment given in session 2. The results indicate that diazepam blocks the acquisition of fear-potentiation of startle responses in man, as in animals, but does not prevent the expression of a previously learned response.
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Affiliation(s)
- J C Scaife
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Nottingham, UK
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Shishkina GT, Kalinina TS, Popova NK, Dygalo NN. Influence of neonatal short-term reduction in brainstem alpha2A-adrenergic receptors on receptor ontogenesis, acoustic startle reflex, and prepulse inhibition in rats. Behav Neurosci 2005; 118:1285-92. [PMID: 15598137 DOI: 10.1037/0735-7044.118.6.1285] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neonatal treatments can disrupt prepulse inhibition (PPI) of startle response later in life. Alpha2A-adrenergic receptors (alpha2A-ARs) regulate the release of brain neurotransmitters that may influence PPI. The authors examined the effects of short-term reduction in the neonatal brainstem alpha2A-ARs on subsequent development of this receptor system and acoustic startle reflex in rats. Administration of antisense oligodeoxynucleotide complementary to the alpha2A-ARs on Days 2-4 of life reduced receptor expression in the brainstem by Day 5. The treatment increased alpha2-AR numbers in the cortex, hippocampus, and amygdala at 40 days of age, and in cortex and hypothalamus at 90 days of age. Transient increases in hippocampal and amygdalar alpha2-ARs were accompanied by attenuation of acoustic startle response and impairment of PPI.
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MESH Headings
- Adrenergic alpha-Antagonists/pharmacokinetics
- Age Factors
- Analysis of Variance
- Animals
- Animals, Newborn
- Behavior, Animal
- Brain/anatomy & histology
- Brain/drug effects
- Brain/physiology
- Brain Stem/drug effects
- Brain Stem/metabolism
- Gene Expression Regulation, Developmental/drug effects
- Idazoxan/analogs & derivatives
- Idazoxan/pharmacokinetics
- Inhibition, Psychological
- Oligonucleotides, Antisense/pharmacology
- Protein Binding/drug effects
- RNA, Messenger/biosynthesis
- Radioligand Assay/methods
- Random Allocation
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-2/genetics
- Receptors, Adrenergic, alpha-2/metabolism
- Reflex, Acoustic/drug effects
- Reflex, Acoustic/physiology
- Reflex, Startle/drug effects
- Reflex, Startle/physiology
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Tritium/pharmacokinetics
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Kaviani H, Gray JA, Checkley SA, Raven PW, Wilson GD, Kumari V. Affective modulation of the startle response in depression: influence of the severity of depression, anhedonia, and anxiety. J Affect Disord 2004; 83:21-31. [PMID: 15546642 DOI: 10.1016/j.jad.2004.04.007] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 04/20/2004] [Accepted: 04/23/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND The amplitude of the startle reflex response is known to be influenced by the concomitant presentation of affect-toned material--if it is positive affect-toned, the reflex is inhibited, and if it is negative affect-toned, the reflex is augmented. Abundant evidence demonstrates the utility of the affect-startle paradigm as a significant tool for measuring both positive and negative emotions. We applied this paradigm to study emotional reactivity in depression, particularly in relation to symptoms of depression, anhedonia, and anxiety. METHODS Depressed patients (22) and controls (22) were shown a series of film clips, consisting of two clips with positive valence, two with negative valence, and two with relatively neutral valence. The startle response was measured in reaction to the acoustic startle-eliciting stimuli presented three times binaurally during each clip. RESULTS Highly depressed and anhedonic patients, relative to controls, showed a reduced mood (self-ratings) and a lack of startle modulation in response to affective film clips whereas patients relatively low on depression/anhedonia displayed a reduced mood only with pleasant clips and a normal pattern of affective startle modulation. Anhedonia and depression were highly positively correlated but neither correlated with anxiety. Anxious patients displayed larger reflexes across all clips and showed a reduced mood modulation with pleasant, but not unpleasant, clips. LIMITATIONS The large majority of patients was medicated with antidepressants which may have influenced the results. CONCLUSIONS. Reactivity to pleasant stimuli is diminished in patients suffering from low levels of depression and/or anhedonia, but reactivity even to unpleasant stimuli seems compromised at high levels of depression and/or anhedonia. Anxiety is associated with hyperstartle responding.
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Affiliation(s)
- H Kaviani
- Department of Psychology, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
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17
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Lähdesmäki J, Sallinen J, MacDonald E, Scheinin M. Alpha2A-adrenoceptors are important modulators of the effects of D-amphetamine on startle reactivity and brain monoamines. Neuropsychopharmacology 2004; 29:1282-93. [PMID: 15039766 DOI: 10.1038/sj.npp.1300428] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Amphetamines are commonly used to treat attention-deficit hyperactivity disorder, but are also widely abused. They are employed in schizophrenia-related animal models as they disrupt the prepulse inhibition (PPI) of the acoustic startle response. The behavioral effects of amphetamines have mainly been attributed to changes in dopamine transmission, but they also involve increases in the synaptic concentrations of norepinephrine (NE). alpha2-Adrenoceptors (alpha2-ARs) regulate the excitability and transmitter release of brain monoaminergic neurons mainly as inhibitory presynaptic auto- and heteroreceptors. Modulation of acoustic startle and its PPI by the alpha2A-AR subtype was investigated with mice lacking the alpha2A-AR (alpha2A-KO) and their wild-type (WT) controls, without drugs and after administration of the alpha2-AR agonist dexmedetomidine or the antagonist atipamezole. The interaction of D-amphetamine (D-amph) and the alpha2-AR-noradrenergic neuronal system in modulating startle reactivity and in regulating brain monoamine metabolism was assessed as the behavioral and neurochemical responses to D-amph alone, or to the combination of D-amph and dexmedetomidine or atipamezole. alpha2A-KO mice were supersensitive to both neurochemical and behavioral effects of D-amph. Brain NE stores of alpha2A-KO mice were depleted by D-amph, revealing the alpha2A-AR as essential in modulating the actions of D-amph. Also, increased startle responses and more pronounced disruption of PPI were noted in D-amph-treated alpha2A-KO mice. alpha2A-AR also appeared to be responsible for the startle-modulating effects of alpha2-AR drugs, since the startle attenuation after the alpha2-AR agonist dexmedetomidine was absent in alpha2A-KO mice, and the alpha2-AR antagonist atipamezole had opposite effects on the startle reflex in alpha2A-KO and WT mice.
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Affiliation(s)
- Janne Lähdesmäki
- 1Department of Pharmacology and Clinical Pharmacology, University of Turku, Turku, Finland
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18
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Graham SJ, Scaife JC, Balboa Verduzco AM, Langley RW, Bradshaw CM, Szabadi E. Effects of quetiapine and haloperidol on prepulse inhibition of the acoustic startle (eyeblink) response and the N1/P2 auditory evoked response in man. J Psychopharmacol 2004; 18:173-80. [PMID: 15260904 DOI: 10.1177/0269881104042615] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Contraction of the orbicularis oculi muscle in response to a sudden loud sound (acoustic startle response) and the N1/P2 component of the auditory evoked potential are both attenuated when a brief low-intensity stimulus is presented 30-500 ms before the 'startle-eliciting' stimulus (PPI). Here, we report the effects of the 'atypical' antipsychotic drug quetiapine and the 'conventional' antipsychotic haloperidol on these responses. Sixteen males (aged 19-38 years) participated in four sessions at 7-day intervals, in which they received quetiapine 12.5 mg, quetiapine 25 mg, haloperidol 3 mg and placebo, according to a balanced double-blind design. Electromyographic (EMG) responses of the orbicularis oculi muscle and N1/P2 auditory evoked potentials were recorded in a 20-min session, 2 h after treatment. Subjects received 40 trials in which 1-kHz sounds were presented: (i) 40 ms, 115 dB ('pulse alone' trials) and (ii) 40 ms, 85 dB, followed after 120 ms by 40 ms, 115 dB ('prepulse/pulse' trials). Mean amplitudes of the EMG response and the N1/P2 potential were derived from the pulse-alone trials and, in each case, percentage PPI was calculated. Serum prolactin was measured after each treatment, and autonomic (heart rate, blood pressure, salivation) and psychological (visual analogue self-ratings of mood and alertness, critical flicker fusion frequency) measures were taken before and after each treatment. Quetiapine 12.5 mg and 25 mg significantly reduced the amplitude of the EMG response without altering its inhibition by prepulses; haloperidol had no effect on EMG response amplitude or PPI. Neither drug affected N1/P2 amplitude or PPI of this response. Quetiapine, but not haloperidol, reduced subjective alertness and critical flicker fusion frequency. Haloperidol, but not quetiapine, elevated serum prolactin level. The ability of quetiapine to attenuate the startle response may reflect its sedative action.
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Affiliation(s)
- S J Graham
- Division of Psychiatry, University of Nottingham, Nottingham, UK
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19
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Abstract
OBJECTIVE To provide an overview of startle reflex methodologies applied to the examination of emotional and motivational states in humans and to review the findings in different forms of psychopathology. METHODS Pertinent articles were searched mostly via MEDLINE and PsycINFO. RESULTS The startle reflex is a non-invasive translational tool of research that bridges the gap between animal and human investigations. Startle is used to study fear and anxiety, affective disturbances, sensitization, motivational states, and homeostasis. CONCLUSIONS The startle reflex is highly sensitive to various factors that are of interest in the studies of emotional disorders and has promoted new areas of investigations in psychiatry. However, research in psychiatry is still in its infancy and most findings await replication. Future progress will benefit from the development of innovative and powerful designs tailored to investigate specific disorders. SIGNIFICANCE The startle reflex has utility as a research tool to examine trauma-related disorders, fear learning, drug addiction, and to contrast affective states and emotional processing across diagnostic groups, but its usefulness as a diagnostic tool is limited.
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Affiliation(s)
- Christian Grillon
- National Institute of Mental Health, DHHS, Mood and Anxiety Disorders Program, 15K North Drive, Bldg 15K, MSC 2670, Bethesda, MD 20895, USA.
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20
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Grillon C, Cordova J, Levine LR, Morgan CA. Anxiolytic effects of a novel group II metabotropic glutamate receptor agonist (LY354740) in the fear-potentiated startle paradigm in humans. Psychopharmacology (Berl) 2003; 168:446-54. [PMID: 12709777 DOI: 10.1007/s00213-003-1444-8] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2002] [Accepted: 02/26/2003] [Indexed: 10/26/2022]
Abstract
RATIONALE LY354740, a structural analogue of glutamate that shows specificity at the mGluR2/3 receptor, has anxiolytic effects in animal models. OBJECTIVE This study investigated the anxiolytic effects of LY354740 in humans using the fear-potentiated startle reflex methodology. METHODS Subjects were given either placebo (n=16), 20 mg LY354740 (n=15), or 200 mg LY354740 (n=13). The fear-potentiated startle tests examined startle potentiation to shock anticipation and to darkness. RESULTS Consistent with previous results, startle was increased by threat of shock and by darkness. LY354740 did not affect baseline startle. Correspondingly, subjects did not report LY354740 to be sedative. LY354740 significantly reduced the increase in startle magnitude during shock anticipation, but not during darkness. Subjective reports of state anxiety and negative affectivity during the fear-potentiated startle tests were also reduced in a dose-dependent manner by LY354740. CONCLUSIONS These results suggest that LY354740 has an anxiolytic profile in humans without being sedative.
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Affiliation(s)
- Christian Grillon
- NIMH/NIH/DHHS, Mood and Anxiety Disorder Program, 15K North Drive, MSC 2670, Bethesda, MD 20892-2670, USA.
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21
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Kumari V, Zachariah E, Galea A, Jones HC, Das M, Mehrotra R, Taylor D, Sharma T. Effects of acute procyclidine administration on prepulse inhibition of the startle response in schizophrenia: a double-blind, placebo-controlled study. J Psychopharmacol 2003; 17:89-95. [PMID: 12680744 DOI: 10.1177/0269881103017001710] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Prepulse inhibition (PPI) of the startle response refers to a reduction in response to a strong stimulus (pulse) if this is preceded shortly by a weak non-startling stimulus (prepulse). Consistent with theories of deficiencies in early stages of information processing, PPI is found to be reduced in patients with schizophrenia. Atypical antipsychotics are found to be more effective than typical antipsychotics in improving PPI in this population. Anticholinergic drugs are often used to control extrapyramidal symptoms induced by antipsychotic medication, especially by typical antipsychotics, in schizophrenic patients and are known to disrupt cognitive functions in both normal and schizophrenic populations. The effect of anticholinergics on PPI in schizophrenia has not yet been examined. This study determined the effects of procyclidine, an anticholinergic drug, on PPI in patients with schizophrenia given risperidone or quetiapine and not on any anticholinergic drugs, employing a placebo-controlled, cross-over design. Under double-blind conditions, subjects were administered oral 15 mg procyclidine and placebo on separate occasions, 2 weeks apart, and tested for acoustic PPI (prepulse 8 dB and 15 dB above the background and delivered with 30-ms, 60-ms and 120-ms prepulse-to-pulse intervals). Procyclidine significantly impaired PPI compared to placebo (assessed as percentage reduction) with 60-ms prepulse-to-pulse trials and increased the latencies to response peak across all trials. The use of anticholinergics needs to be carefully controlled/examined in investigations of information processing deficits using a PPI model and reduced to the minimum level in clinical care of schizophrenia.
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Affiliation(s)
- Veena Kumari
- Section of Cognitive Psychopharmacology, Division of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, London, UK.
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22
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Small KM, Forbes SL, Rahman FF, Bridges KM, Liggett SB. A four amino acid deletion polymorphism in the third intracellular loop of the human alpha 2C-adrenergic receptor confers impaired coupling to multiple effectors. J Biol Chem 2000; 275:23059-64. [PMID: 10801795 DOI: 10.1074/jbc.m000796200] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The alpha(2)-adrenergic receptors (alpha(2)ARs) play a critical role in modulating neurotransmitter release in the central and peripheral sympathetic nervous systems. A polymorphism of the alpha(2)AR subtype localized to human chromosome 4 (the pharmacologic alpha(2C)AR subtype) within an intracellular domain has been identified in normal individuals. The polymorphism (denoted Del322-325) is because of an in-frame 12-nucleic acid deletion encoding a receptor lacking Gly-Ala-Gly-Pro in the third intracellular loop. To delineate the functional consequences of this structural alteration, Chinese hamster ovary cells were permanently transfected with constructs encoding wild-type human alpha(2C)AR and the polymorphic receptor. The Del322-325 variant had decreased high affinity agonist binding (K(H) = 7.3 +/- 0.95 versus 3.7 +/- 0.43 nm; %R(H) = 31 +/- 4 versus 49 +/- 4) compared with wild-type indicating impaired formation of the agonist-receptor-G protein complex. The polymorphic receptor displayed markedly depressed epinephrine-promoted coupling to G(i), inhibiting adenylyl cyclase by 10 +/- 4.3% compared with 73 +/- 2.4% for wild-type alpha(2C)AR. This also was so for the endogenous ligand norepinephrine and full and partial synthetic agonists. Depressed agonist-promoted coupling to the stimulation of MAP kinase ( approximately 71% impaired) and inositol phosphate production ( approximately 60% impaired) was also found with the polymorphic receptor. The Del322-325 receptor was approximately 10 times more frequent in African-Americans compared with Caucasians (allele frequencies 0.381 versus 0.040). Given this significant loss of function phenotype in several signal transduction cascades and the skewed ethnic prevalence, Del322-325 represents a pharmacoethnogenetic locus and may also be the basis for interindividual variation in cardiovascular or central nervous system pathophysiology.
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Affiliation(s)
- K M Small
- Departments of Medicine and Molecular Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA
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23
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Kumari V, Cotter PA, Mulligan OF, Checkley SA, Gray NS, Hemsley DR, Thornton JC, Corr PJ, Toone BK, Gray JA. Effects of d-amphetamine and haloperidol on latent inhibition in healthy male volunteers. J Psychopharmacol 1999; 13:398-405. [PMID: 10667617 DOI: 10.1177/026988119901300411] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Latent inhibition (LI) refers to a retardation of learning about the consequences of a stimulus when that stimulus has been passively presented a number of times without reinforcement. Acute positive-symptom schizophrenics, normal volunteers who score high on questionnaire measures of schizotypy and non-patients or animals treated with dopamine agonists show reduced LI. Neuroleptic drugs, such as haloperidol, administered at low doses, potentiate LI and effectively reverse disruption of LI induced by dopamine agonists in animals. However, a high dose of haloperidol, administered on its own, has been found to reduce LI. We examined the effects on LI of acute oral administration of an indirect dopamine-agonist, d-amphetamine (5 mg), and a nonselective dopamine receptor antagonist, haloperidol (5 mg), in normal male volunteers, using an associative learning task. Replicating previous reports, we found that d-amphetamine reduced LI; haloperidol also reduced LI, but only in subjects who scored low on the Psychoticism scale of the Eysenck Personality Questionnaire. In a subsequent study, no effect was found of 2 mg oral haloperidol administration on LI. The effect of 5 mg haloperidol on LI is interpreted as similar to that observed with a high dose of haloperidol in rats.
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Affiliation(s)
- V Kumari
- Department of Psychology, Institute of Psychiatry, London, UK.
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Bitsios P, Philpott A, Langley RW, Bradshaw CM, Szabadi E. Comparison of the effects of diazepam on the fear-potentiated startle reflex and the fear-inhibited light reflex in man. J Psychopharmacol 1999; 13:226-34. [PMID: 10512076 DOI: 10.1177/026988119901300303] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It has been shown previously that the amplitude of the acoustic startle reflex is enhanced, and the amplitude of the light reflex reduced, when subjects anticipate an aversive event, compared to periods when subjects are resting ('fear-potentiated startle reflex' and 'fear-inhibited light reflex'). We examined whether the anxiolytic diazepam would reverse the effects of threat on the startle and pupillary reflexes. Twelve male volunteers participated in three weekly sessions in which they received oral treatment with placebo, diazepam 5 mg and diazepam 10 mg, according to a balanced crossover double-blind design. One hour after ingestion of the treatments, miotic responses to light pulses and electromyographic responses of the orbicularis oculi muscle to sound pulses were elicited during alternating periods in which the threat of an electric shock (electrodes attached to the subject's wrist) was present (THREAT) and absent (SAFE). The THREAT condition was associated with a significant increase in the amplitude of the electromyographic (EMG) response, a significant reduction of the miotic response amplitude, and an increase in self-rated anxiety. Diazepam attenuated all these effects of THREAT. Diazepam did not affect the amplitude of the miotic response under the SAFE condition, but did suppress the EMG response under this condition. These results confirm the validity of the fear-potentiated startle reflex and fear-inhibited light reflex as laboratory models of human anxiety, and reveal some differences between the effects of diazepam on the two reflexes.
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Affiliation(s)
- P Bitsios
- Division of Psychiatry, University of Nottingham, UK
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25
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Abstract
It has been widely reported that the eyeblink component of the acoustic startle reflex can be modulated by emotionally-toned slide stimuli; pleasant slides reduce eyeblink amplitudes whereas unpleasant slides enhance them. The present study examines the modulation of the acoustic startle reflex by short (2-min) film-clips classified as pleasant, unpleasant or neutral, on the basis of subjective ratings. These film-clips were also evaluated with respect to their test-retest reliability in producing affective states as well as modulating startle reflexes. Overall, results showed significant reduction of startle during pleasant clips and augmentation during unpleasant clips. However, on first showing, one of the two unpleasant clips (a medical demonstration film depicting details of toe surgery) actually inhibited the startle reflex rather than augmented it. This is discussed in terms of the proposition that only stimuli which arouse fear can be guaranteed to augment startle; stimuli that are repulsive may produce perceptual and emotional 'blunting' that reduces startle amplitude.
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Affiliation(s)
- H Kaviani
- Department of Psychology, University of London, UK
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26
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Abstract
AIMS The eye-blink response following sudden acoustic noise bursts is part of the startle reflex. The magnitude of the startle response can be attenuated by presentation of a weak stimulus before the 'startle-eliciting' stimulus (prepulse inhibition, PPI). PPI is a stable finding in awake humans but may be altered by anaesthetic drugs. We investigated whether the application of benzodiazepines altered the magnitude of PPI in healthy male volunteers. METHODS In an open-label noncontrolled investigation, the effect of the benzodiazepine agonist midazolam on PPI was assessed in the absence and presence of the antagonist flumazenil. After an initial control period of 60 min three consecutive periods, each of 60 min, with progressively increasing concentrations of midazolam were studied (0. 02, 0.06, 0.14 mg kg-1 h-1 ). A final 60 min period during the administration of flumazenil (0.004 mg kg-1 h-1 ) and while the agonist was still present was also studied. Drug was administered intravenuously as a combination of bolus, 50% of total dose and continuous infusion over the 60 min period. Electromyographic (EMG) response of the right orbicularis oculi muscle was used to assess the startle response to noise bursts of 50 ms duration (95 dB(A)). Noise bursts were randomly preceded by nonstartling prepulses (800 Hz sinus, 50 ms duration, 65 dB(A), prepulse to noise interval 120 ms). The magnitude of PPI was calculated by dividing the EMG response to nonprepulsed stimuli by the response to prepulsed stimuli for each individual and period. Eleven subjects participated in the study, two of them were excluded from the statistical analysis because startle responses could not be reliably elicited (final sample size n=9). RESULTS The magnitude of PPI was inversely related to the concentration of midazolam. This relationship was described by a sigmoidal Emax model, giving an Emax of 0.65+/-0.13, an ED50 of 33.9+/-10.9 ng ml-1 and gamma of 3.5+/-1.0. During infusion of flumazenil and in the presence of midazolam, the magnitude of PPI increased by 0.11 (95% CI, 0-0.22, P</=0.04), which is consistent with its mode of action as a benzodiazepine antagonist. CONCLUSIONS In healthy male volunteers the magnitude of PPI varies according to agonism and antagonism of benzodiazepine receptors, suggesting that the assessment of PPI may be potentially useful to monitor the sedative effect of benzodiazepines in the clinical setting.
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Affiliation(s)
- H Schächinger
- Division of Intensive Care Medicine, Department of Internal Medicine, University Hospital, Basel, Switzerland
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27
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Abstract
The aim of this study was to examine the effect of repeated testing on prepulse inhibition (PPI) and habituation of the startle reflex. Fifteen healthy control subjects (eight males, mean age 30 years; seven females, mean age 29 years) were tested on three occasions across the same day separated by a minimum of 2 h. An acoustic probe of 40-msec bursts of 116 dB(A) white noise over a continuous background noise of 70 dB(A) was presented binaurally through headphones and the eye-blink component of the startle response was measured taking electromyographic recordings from the right orbicularis oculi. The test session was identical at each time point and consisted of two blocks of 12 randomly mixed trials of four pulse-alone, four 60-msec prepulse and four 120-msec prepulse trials enclosed by two blocks each of six pulse-alone trials. There was huge variation in individual response magnitude that was independent of subsequent PPI in both women and men. Women showed greater PPI in the second half of sessions with the 120-msec prepulse only; but PPI was not altered significantly in either group between sessions across the day. In general, there was good test-retest reliability of PPI especially within trial type. Normal reflex habituation occurred across sessions and this effect was preserved in sessions across the day. Latency of response was significantly reduced in a session by the 60-msec trial type compared to the 120-msec trial type, as previously reported. Our results suggest that measures of PPI and habituation of the startle response are appropriate and reliable for a within-subject, test-retest design.
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Affiliation(s)
- K Abel
- Department of Psychological Medicine, King's College Hospital and Institute of Psychiatry, London, UK.
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Sallinen J, Haapalinna A, Viitamaa T, Kobilka BK, Scheinin M. Adrenergic alpha2C-receptors modulate the acoustic startle reflex, prepulse inhibition, and aggression in mice. J Neurosci 1998; 18:3035-42. [PMID: 9526020 [PMID: 9526020 DOI: 10.1523/jneurosci.18-08-03035.1998] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Studies on animal models of stress, anxiety, aggression, and sensorimotor gating have linked specific monoamine neurotransmitter abnormalities to the cognitive and behavioral disturbances associated with many affective neuropsychiatric disorders. Although alpha2-adrenoceptors (alpha2-ARs) have been suggested to have a modulatory role in these disorders, the specific roles of each alpha2-AR subtype (alpha2A, alpha2B, and alpha2C) are largely unknown. The restricted availability of relevant animal models and the lack of subtype-selective alpha2-AR drugs have precluded detailed studies in this area. Therefore, transgenic mice were used to study the possible role of the alpha2C-AR subtype in two well established behavioral paradigms: prepulse inhibition (PPI) of the startle reflex and isolation-induced aggression. The alpha2C-AR-altered mice appear grossly normal, but subtle changes have been observed in their brain dopamine (DA) and serotonin (5-HT) metabolism. In this study, the mice with targeted inactivation of the gene encoding alpha2C-ARs (alpha2C-KO) had enhanced startle responses, diminished PPI, and shortened attack latency in the isolation-aggression test, whereas tissue-specific overexpression of alpha2C-ARs (alpha2C-OE) was associated with opposite effects. Correlation analyses suggested that both the magnitude of the startle response and its relative PPI (PPI%) were modulated by the mutations. In addition, the differences in PPI, observed between drug-naive alpha2C-OE mice and their wild-type controls, were abolished by treatment with a subtype nonselective alpha2-agonist and antagonist. Thus, drugs acting via alpha2C-ARs might have therapeutic value in disorders associated with enhanced startle responses and sensorimotor gating deficits, such as schizophrenia, attention deficit disorder, post-traumatic stress disorder, and drug withdrawal.
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Kumari V, Toone B, Gray JA. Habituation and prepulse inhibition of the acoustic startle reflex: Effects of smoking status and psychosis-proneness. Personality and Individual Differences 1997. [DOI: 10.1016/s0191-8869(97)00045-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kumari V, Corr PJ, Wilson GD, Kaviani H, Thornton JC, Checkley SA, Gray JA. Personality and modulation of the startle reflex by emotionally-toned filmclips. Personality and Individual Differences 1996. [DOI: 10.1016/s0191-8869(96)00157-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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