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Lagami D, Shupak A, Jamison A, Tal D. The Vestibular Time Constant and Clinical Response to Antimotion Sickness Medication. Ear Hear 2023; 44:1404-1409. [PMID: 37221635 DOI: 10.1097/aud.0000000000001385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
OBJECTIVE The therapeutic effects of antimotion sickness medications involve suppression of several components along the vestibular system. Scopolamine-based medications have proved to be the most effective anti-seasickness agents. However, there is high variability in individual responses. The vestibular nuclei, in which the vestibular time constant is modulated, contain acetylcholine receptors which are affected by scopolamine. The hypothesis of the study was that successful seasickness prevention by scopolamine requires vestibular suppression to be reflected by the shortening of the vestibular time constant. DESIGN Subjects were 30 naval crew members suffering from severe seasickness and were treated with oral scopolamine. The study participants were defined as responsive or non-responsive to the anti-seasickness medication according to the clinical outcome: successful response to scopolamine was defined as a reduction of seasickness severity from the highest score of 7 according to the Wiker scale to 4 or less. Scopolamine and placebo were assigned to each subject in a crossover, double-blind design. The horizontal semicircular canal time constant was evaluated by a computerized rotatory chair before, 1 and 2 hours after drug or placebo administration. RESULTS The vestibular time constant was significantly shortened from 16.01 ± 3.43 seconds to 12.55 ± 2.40 seconds ( p < 0.001) in the scopolamine-responsive group but not in the nonresponsive group. In contrast, vestibular time constant values were 13.73 ± 4.08 and 12.89 ± 4.48 for baseline and 2 hours measurements, respectively. This change was not statistically significant. CONCLUSIONS Reduction in the vestibular time constant after scopolamine administration can be used to predict whether motion sickness alleviation will occur. This will enable the administration of appropriate pharmaceutical treatment without the need for prior exposure to sea conditions.
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Affiliation(s)
- Daniel Lagami
- Motion Sickness and Human Performance Laboratory, Israel Naval Medical Institute, IDF Medical Corps, Haifa, Israel
- Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Avi Shupak
- Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
- Unit of Otoneurology, Lin Medical Center, Haifa, Israel
- Department of Communication Science and Disorders, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Anna Jamison
- Motion Sickness and Human Performance Laboratory, Israel Naval Medical Institute, IDF Medical Corps, Haifa, Israel
| | - Dror Tal
- Motion Sickness and Human Performance Laboratory, Israel Naval Medical Institute, IDF Medical Corps, Haifa, Israel
- Department of Military Medicine, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
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Ertekin A, Atay E, Bozkurt E, Aslan E. Effect of buscopan, a compound that alleviates cramps, on the developing nervous system of the chick embryo. Birth Defects Res 2021; 113:1140-1151. [PMID: 34050726 DOI: 10.1002/bdr2.1929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 04/30/2021] [Accepted: 05/20/2021] [Indexed: 11/08/2022]
Abstract
BACKGROUND Buscopan is used to treat stomach cramps including those resulting from irritable bowel syndrome, bladder cramps, and pain related to menstruation. Its pregnancy category is determined as C. It has been shown in experimental animal studies that the drug has a negative effect on the embryo, but sufficient and well-controlled studies have not been conducted in humans. The aim of this study is to investigate effects of buscopan on the development of the neural tube (NT) in chick embryos. METHODS Sixty specific pathogen-free (SPF) fertilized eggs were used. SPF eggs were placed in an incubator and divided into six groups at 28 hr of incubation. Five different doses (low to high) of buscopan were injected sub-blastodermally. At the end of 48 hr, the embryos were evaluated morphologically and histopathologically. The argyrophilic nucleolar-organizing region (AgNOR) method was used in this study to determine the proliferation activity of cells in NT development in chick embryos. AgNOR number and total AgNOR area/nuclear area (TAA/NA) were detected for each embryo. RESULTS Depending on the dose, the embryo's crown-rump length and somite number decreased (p < .05). Significant differences were detected among all groups for mean AgNOR number (p < .05) and TAA/NA ratio (p < .05). CONCLUSIONS Considering the average count of AgNOR cells and TAA/NA ratio, it was found that there was a decrease in cell division depending on the dose. It was determined that buscopan treatment on chick embryos adversely affected early nervous system and NT development.
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Affiliation(s)
- Ayşe Ertekin
- Department of Emergency Medicine, Faculty of Medicine, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey
| | - Emre Atay
- Department of Anatomy, Faculty of Medicine, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey
| | - Erhan Bozkurt
- Department of Internal Medicine, Faculty of Medicine, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey
| | - Esra Aslan
- Department of Histology Embryology, Faculty of Medicine, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey
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3
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Muscarinic and Nicotinic Modulation of Memory but not Verbal Problem-solving. Cogn Behav Neurol 2020; 32:278-283. [PMID: 31800488 DOI: 10.1097/wnn.0000000000000208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Aspects of cognitive flexibility are modulated by the noradrenergic system, which is important in arousal and attention. Acetylcholine also modulates arousal and attention, as well as working memory. Effects of muscarinic and nicotinic antagonism on memory are well established. Our purpose was to test whether muscarinic and nicotinic antagonism affect aspects of cognitive flexibility, specifically verbal problem-solving, as well as memory, given acetylcholine's role in attention and arousal. Eighteen participants attended three testing sessions. Two hours before testing, participants received either 0.6 mg scopolamine, 10 mg mecamylamine, or placebo. Then, participants were tested on three memory tasks (Buschke Selective Reminding Test [BSRT], California Verbal Learning Test [CVLT], Rey Complex Figure Test), two verbal problem-solving/cognitive flexibility tasks (Compound Remote Associates Test, a timed anagram test), and a spatial inductive reasoning task (Raven's Progressive Matrices). Task order and drug order were counterbalanced. Memory impairment was seen on one BSRT measure and multiple CVLT measures with scopolamine, and with one BSRT measure with mecamylamine. There were no effects of either drug on any of the tasks involving cognitive flexibility, including verbal problem-solving. Specific memory impairments were detected using muscarinic, and to a marginal extent, nicotinic antagonists, as expected, but no effect was seen on cognitive flexibility. Therefore, although both the noradrenergic and cholinergic systems play important roles in arousal and cortical signal-to-noise processing, the cholinergic system does not appear to have the same effect as the noradrenergic system on cognitive flexibility, including verbal problem-solving.
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Bukala BR, Browning M, Cowen PJ, Harmer CJ, Murphy SE. Overnight transdermal scopolamine patch administration has no clear effect on cognition and emotional processing in healthy volunteers. J Psychopharmacol 2019; 33:255-257. [PMID: 30526264 DOI: 10.1177/0269881118817161] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
There has been increasing interest in the antidepressant effects of the muscarinic cholinergic receptor antagonist scopolamine. Here we assess, for the first time, whether a transdermal scopolamine patch is sufficient to induce changes in cognition that are consistent with the reported cognitive and antidepressant effects of scopolamine. A scopolamine or placebo patch was administered to healthy volunteers ( n=33) for 17 h in a double-blind, between-subject procedure. There was no clear effect of scopolamine patch on emotional cognition, verbal or working memory, suggesting that the effective dose of scopolamine available through the patch is too low to represent a viable antidepressant mechanism.
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Affiliation(s)
| | | | - Philip J Cowen
- Department of Psychiatry, University of Oxford, Oxford, UK
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5
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Tsui CKY, Dringenberg HC. Role of cholinergic-muscarinic receptors in visual discrimination performance of rats: importance of stimulus load. Behav Brain Res 2012; 238:23-9. [PMID: 23078949 DOI: 10.1016/j.bbr.2012.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 10/01/2012] [Accepted: 10/06/2012] [Indexed: 11/15/2022]
Abstract
Central cholinergic transmission has long been implicated in various cognitive processes, including memory acquisition, consolidation, and attentional processes. Here, we examined the role of muscarinic receptors in visual discrimination performance under conditions of altered visual information availability. Adult rats were trained to discriminate two visual cues (indicating the presence and absence of a hidden escape platform, respectively) in a water maze-based, trapezoidal-shaped apparatus. Following task acquisition, testing continued with two types of trials: regular trials (RTs; both visual cues present, identical to training conditions) and probe trials (PTs; only one of the two cues present). In Experiment 1, removal of one visual cue on PTs impaired discrimination performance. Moreover, scopolamine administration (0.125-1.0 mg/kg, i.p.) tended to further suppress performance in a dose-dependent manner on PTs, while discriminations on RTs were left intact. In Experiment 2, these results were confirmed and extended by showing that PT (one visual cue) performance could improve with training in undrugged, but not in scopolamine-treated rats. Together, these experiments reveal that visual discrimination performance of rats benefits from the concurrent availability of two visual cues that provide complimentary and consistent information. Furthermore, muscarinic receptors are particularly important under conditions of reduced visual information availability, as well as in the adoption of new behavioral strategies, such as switching from two-cue to single-cue guided navigation.
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Affiliation(s)
- Claudia K Y Tsui
- Department of Psychology, Queen's University, Kingston, Ontario, K7L 3N6, Canada
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6
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Cho W, Maruff P, Connell J, Gargano C, Calder N, Doran S, Fox-Bosetti S, Hassan A, Renger J, Herman G, Lines C, Verma A. Additive effects of a cholinesterase inhibitor and a histamine inverse agonist on scopolamine deficits in humans. Psychopharmacology (Berl) 2011; 218:513-24. [PMID: 21644059 DOI: 10.1007/s00213-011-2344-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 05/03/2011] [Indexed: 11/30/2022]
Abstract
RATIONALE Enhancement of histaminergic neurotransmission or histaminergic plus cholinergic neurotransmission may represent novel strategies for improving cognition in Alzheimer's disease. OBJECTIVE To evaluate the effects of a novel histamine H3 receptor inverse agonist (MK-3134), an acetylcholinesterase inhibitor (donepezil), and their combination in attenuating the cognitive impairment associated with scopolamine. METHODS Thirty-one subjects were randomized, and 28 completed this double-blind, placebo-controlled, five-period crossover study. Cognition was assessed using the Groton Maze Learning Task (GMLT) as the primary outcome measure. The two primary hypotheses were that donepezil 10 mg and MK-3134 25 mg, respectively, would attenuate scopolamine (0.5 mg)-induced impairment as measured by the GMLT over the first 12 h after scopolamine administration (AUC(1-12) (h)). A secondary hypothesis was that the combination of donepezil and MK-3134 would attenuate scopolamine-induced cognitive impairment to a greater extent than either agent alone as measured by the GMLT AUC(1-12 h). RESULTS The primary and secondary hypotheses were not met. Upon examining the time course of the scopolamine effects (an exploratory objective), peak effects were generally observed around 2 h after scopolamine administration. Administration of MK-3134 or donepezil improved performance on the GMLT at the 2-h time point, rather than AUC(1-12 h), compared with scopolamine alone. Moreover, it appeared that the combination of MK-3134 and donepezil blunted the scopolamine effect to a greater extent than either drug alone. CONCLUSIONS Exploratory analyses provide evidence for cognitive improvement through inverse agonism of the H3 histamine receptor and for cooperation between human cholinergic and histaminergic neurotransmitter systems. (ClinicalTrials.gov trial registration number: NCT01181310).
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Affiliation(s)
- William Cho
- Merck Sharp & Dohme Corp, Whitehouse Station, NJ, USA.
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Abstract
As indicated by the profound cognitive impairments caused by cholinergic receptor antagonists, cholinergic neurotransmission has a vital role in cognitive function, specifically attention and memory encoding. Abnormally regulated cholinergic neurotransmission has been hypothesized to contribute to the cognitive symptoms of neuropsychiatric disorders. Loss of cholinergic neurons enhances the severity of the symptoms of dementia. Cholinergic receptor agonists and acetylcholinesterase inhibitors have been investigated for the treatment of cognitive dysfunction. Evidence from experiments using new techniques for measuring rapid changes in cholinergic neurotransmission provides a novel perspective on the cholinergic regulation of cognitive processes. This evidence indicates that changes in cholinergic modulation on a timescale of seconds is triggered by sensory input cues and serves to facilitate cue detection and attentional performance. Furthermore, the evidence indicates cholinergic induction of evoked intrinsic, persistent spiking mechanisms for active maintenance of sensory input, and planned responses. Models have been developed to describe the neuronal mechanisms underlying the transient modulation of cortical target circuits by cholinergic activity. These models postulate specific locations and roles of nicotinic and muscarinic acetylcholine receptors and that cholinergic neurotransmission is controlled in part by (cortical) target circuits. The available evidence and these models point to new principles governing the development of the next generation of cholinergic treatments for cognitive disorders.
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van Ruitenbeek P, Vermeeren A, Riedel W. Histamine H1-receptor blockade in humans affects psychomotor performance but not memory. J Psychopharmacol 2008; 22:663-72. [PMID: 18208925 DOI: 10.1177/0269881107081526] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Results from recent animal studies suggest an important role for histamine in memory functioning. Histaminergic drugs might prove beneficial for people suffering from memory impairment. To determine if histamine is involved in memory functioning this study evaluates the effects of histaminergic dysfunction on memory performance by administrating a H1-antagonist to humans. The study was conducted according to a 4-way, double-blind, crossover design in 20 healthy female volunteers, aged 18-45 years. On each test day subjects completed three test sessions: before and around 2 and 4 h after administration of single oral doses of dexchlorpheniramine 2 mg or 4 mg, scopolamine 1 mg or placebo. Drug effects were assessed using tests of memory, psychomotor and attention performance, and subjective alertness. Results showed that dexchlorpheniramine impaired performance in tests of spatial learning, reaction time, tracking and divided attention but showed no effects on working memory, visual memory, word learning or memory scanning. Scopolamine induced a similar pattern of effects. In addition, both drugs decreased subjective alertness. In conclusion results show that dexchlorpheniramine and scopolamine clearly impaired performance on psychomotor and attention tasks but do not suggest a specific role of the histaminergic system in learning and memory in humans.
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Affiliation(s)
- P van Ruitenbeek
- Experimental Psychopharmacology Unit, Department of Neuropsychology and Psychopharmacology, Brain and Behaviour Institute, Faculty of Psychology, Maastricht University, Maastricht, The Netherlands.
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Irving EA, Upton N. Symptomatic treatment of Alzheimer’s disease: identification of biomarkers to aid translation from bench to bedside. Biomark Med 2007; 1:93-110. [DOI: 10.2217/17520363.1.1.93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the absence of robust pharmacodynamic markers, the potential success of novel therapeutic agents for the symptomatic relief of Alzheimer’s disease is largely unknown until the drugs enter relatively large studies, assessing clinical outcome over a 6-month period. In order to increase the efficiency of future clinical development there is, therefore, a need to identify pharmacodynamic markers of drug response, pharmacodynamic models that allow early prediction of efficacy and markers to aid the stratification of the patient population. Using literature available from cholinesterase inhibitors, memantine and Ginkgo biloba, this review focuses on the identification of potential pharmacodynamic markers/models and highlights the utility of these end points throughout the drug discovery process, from preclinical to clinical development.
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Affiliation(s)
- Elaine A Irving
- GlaxoSmithKline, Neurology and GI CEDD, New Frontiers Science Park North, Third Avenue, Harlow, Essex, CM19 5AW, UK
| | - Neil Upton
- GlaxoSmithKline, Neurology and GI CEDD, New Frontiers Science Park North, Third Avenue, Harlow, Essex, CM19 5AW, UK
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11
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Nachum Z, Shupak A, Gordon CR. Transdermal scopolamine for prevention of motion sickness : clinical pharmacokinetics and therapeutic applications. Clin Pharmacokinet 2006; 45:543-66. [PMID: 16719539 DOI: 10.2165/00003088-200645060-00001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A transdermal therapeutic system for scopolamine (TTS-S) was developed to counter the adverse effects and short duration of action that has restricted the usefulness of scopolamine when administered orally or parenterally. The plaster contains a reservoir of 1.5 mg of scopolamine programmed to deliver 0.5 mg over a 3-day period. A priming dose (140 microg) is incorporated into the adhesive layer to saturate certain binding sites within the skin and to accelerate the achievement of steady-state blood levels. The remainder is released at a constant rate of approximately 5 microg/hour. The protective plasma concentration of scopolamine is estimated to be 50 pg/mL. TTS-S attains that concentration after 6 hours; a steady state of about 100 pg/mL is achieved 8-12 hours after application. Yet 20-30% of subjects failed to attain the estimated protective concentration, and plasma concentrations measured in subjects who failed to respond to TTS-S were lower than in responders. These findings may explain some of the treatment failures. Overall, the product appears to be the approximate functional equivalent of a 72-hour slow intravenous infusion. A combination of transdermal and oral scopolamine (0.3 or 0.6 mg) was effective and well tolerated in producing desired plasma concentrations 1-hour post-treatment. TTS-S has proved to be significantly superior to placebo in reducing the incidence and severity of motion sickness by 60-80%. It was more effective than oral meclizine or cinnarizine, similar to oral scopolamine 0.6 mg or promethazine plus ephedrine, and the same as or superior to dimenhydrinate. The addition of ephedrine or the use of two patches did not improve its efficacy, but rather increased the rate of adverse effects. TTS-S was most effective against motion sickness 8-12 hours after application. Despite previous evidence to the contrary, a recent bioavailability study demonstrated similar intraindividual absorption and sustained clinical efficacy with long-term use of the drug. The adverse effects produced by TTS-S, although less frequent, are qualitatively typical of those reported for the oral and parenteral formulations of this agent. Dry mouth occurs in about 50-60% of subjects, drowsiness in up to 20%, and allergic contact dermatitis in 10%. Transient impairment of ocular accommodation has also been observed, in some cases possibly the result of finger-to-eye contamination. Low-dose pyridostigmine was found effective in preventing cycloplegia but not mydriasis. Adverse CNS effects, including toxic psychosis (mainly in elderly and paediatric patients), have been reported only occasionally, as have difficulty in urinating, headache, rashes and erythema. Adverse effects were not correlated with plasma scopolamine concentrations. TTS-S produced only about half the incidence of drowsiness caused by oral dimenhydrinate or cinnarizine, and a level of adverse effects similar to that found with oral meclizine. Performance is not affected by short-term use. Prolonged or repeated application may cause some impairment of memory storage for new information. However, sea studies revealed significantly less reports of a decrement in performance or drowsiness due to prevention of sea sickness. The recommended dosage is a single TTS-S patch applied to the postauricular area at least 6-8 hours before the anti-motion sickness effect is required. For faster protection, the patch may be applied 1 hour before the journey in combination with oral scopolamine (0.3 or 0.6 mg). After 72 hours, the patch should be removed and a new one applied behind the opposite ear. Its place in therapy is mainly on long journeys (6-12 hours or longer), to avoid repeated oral doses, or when oral therapy is ineffective or intolerable.
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Affiliation(s)
- Zohar Nachum
- Motion Sickness and Human Performance Laboratory, Israel Naval Medical Institute, IDF Medical Corps, Haifa, IsraelDepartment of Obstetrics and Gynecology, Ha'Emek Medical Center, Afula, Israel.
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12
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Affiliation(s)
- Craig R Sherman
- Medical Director, Hope Pharmaceuticals, Scottsdale, Arizona 85260, USA
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13
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Abstract
The strength of the McCollough effect (ME), a pattern-contingent colour aftereffect, has been shown to be inversely related to acetylcholine, being significantly strengthened by (anticholinergic) scopolamine and weakened by (cholinergic) physostigmine delivered before adapting to the ME stimuli. The purpose of the present study was (i) to establish whether the effect of pre-adaptation scopolamine is linearly dose-dependent and (ii) to investigate the effects of scopolamine and physostigmine delivered between adaptation and testing. In experiment 1, ten healthy male volunteers who received placebo, or 0.6 mg, 1.2 mg, or 1.8 mg scopolamine before adapting to ME stimuli showed a significant linear dose-dependence over tests repeated from 10 to 70 min after adaptation. In experiment 2 twelve male volunteers adapted to ME stimuli and then received placebo, 1.2 mg oral scopolamine, or 0.75 mg subcutaneous physostigmine. On subsequent repeated testing, strength of the ME was increased by scopolamine and decreased by physostigmine relative to placebo. Both experiments were double-blind double-dummy repeated measures. These data support the view that the ME is a product of inhibitory mechanisms in the visual system rather than processes involved in associative learning.
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Affiliation(s)
- W Byth
- School of Psychology, Queen's University of Belfast, Northern Ireland, UK.
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14
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Nakamura K, Kurasawa M, Tanaka Y. Scopolamine model of delirium in rats and reversal of the performance impairment by aniracetam. Drug Dev Res 1998. [DOI: 10.1002/(sici)1098-2299(199802)43:2<85::aid-ddr1>3.0.co;2-l] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Schwarz R, Callahan M, Davis R, Jaen J, Tecle H. Development of M1 subtype selective muscarinic agonists for Alzheimer's disease: Translation of in vitro selectivity into in vivo efficacy. Drug Dev Res 1997. [DOI: 10.1002/(sici)1098-2299(199702)40:2<133::aid-ddr4>3.0.co;2-m] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sarter M, Bruno JP, Givens B, Moore H, McGaughy J, McMahon K. Neuronal mechanisms mediating drug-induced cognition enhancement: cognitive activity as a necessary intervening variable. BRAIN RESEARCH. COGNITIVE BRAIN RESEARCH 1996; 3:329-43. [PMID: 8806034 DOI: 10.1016/0926-6410(96)00018-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The conceptual foundations of a research aimed at the determination of potential neuronal, neuropharmacological, and behavioral/cognitive mechanisms mediating drug-induced cognition enhancement are discussed. The available evidence justifies a focus on attentional processes as a target for drug-induced cognition enhancement. Neuropharmacological mechanisms that may mediate drug-induced enhancement of attentional functions are proposed to interact necessarily with attention-associated neuronal activity. The elements of a transsynaptic approach to increase the excitability of basal forebrain cholinergic neurons and hence, attentional functions are discussed. Experimental tests of this hypothesis require the demonstration of interactions between cognition-induced increases in the activity of cortical cholinergic afferents and the effects of putative cognition enhancers. The available data illustrate that the effects of benzodiazepine receptor (BZR) agonists and inverse agonists on cortical acetylcholine (ACh) efflux interact with the state of activity in this system. The feasibility, potential heuristic power, and the experimental and conceptual problems of studies attempting to simultaneously assess drug effects on behavioral/cognitive abilities, ACh efflux, and neuronal activity have been revealed by an experiment intended to correlate performance in a task measuring sustained attention with medial prefrontal ACh efflux and medial prefrontal single-unit activity. The rational development of a psychopharmacology of cognition enhancers requires a union among behavioral/cognitive pharmacology, neuropharmacological and electrophysiological approaches.
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Affiliation(s)
- M Sarter
- Department of Psychology, Ohio State University, Columbus 43210, USA.
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17
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Tariot PN, Patel SV, Cox C, Henderson RE. Age-related decline in central cholinergic function demonstrated with scopolamine. Psychopharmacology (Berl) 1996; 125:50-6. [PMID: 8724448 DOI: 10.1007/bf02247392] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Scopolamine hydrobromide was administered intravenously to 23 normal subjects (40-89 years) in doses of 0.1 mg, 0.25 mg, and 0.5 mg, in a double-blind. Placebo-controlled, random-order fashion. The effects of scopolamine, as compared to placebo, were assessed using a comprehensive cognitive test battery, as well as behavioral and physiological measures. Scopolamine produced the expected dose-dependent impairments in most of the cognitive functions assessed. Behavioral and physiological measures were also affected, but only minimally. More importantly, there was a significant overall correlation between age and scopolamine-impaired performances on psychomotor speed, short-term recall, visual tracking speed, visuo-motor coordination, and sequencing ability. There was, however, some inter-individual variability in this phenomenon. The results provide further evidence that cholinergically mediated cognitive functions show an increased sensitivity to scopolamine with age, albeit with heterogeneity that bears further investigation.
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Affiliation(s)
- P N Tariot
- Department of Psychiatry, University of Rochester School of Medicine and Dentistry, New York, USA
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Abstract
This paper discusses the use of psychological performance tests to assess the effects of environmental stressors. The large number and the variety of performance tests are illustrated, and the differences between performance tests and other psychological tests are described in terms of their design, construction, use, and purpose. The stressor emphasis is on the effects of drugs since that is where most performance tests have found their main application, although other stressors, e.g., fatigue, toxic chemicals, are mentioned where appropriate. Diazepam is used as an example. There is no particular performance emphasis since the tests are intended to have wide applicability. However, vehicle-driving performance is discussed because it has been the subject of a great deal of research and is probably one of the most important areas of application. Performance tests are discussed in terms of the four main underlying models--factor analysis, general information processing, multiple resource and strategy models, and processing-stage models--and in terms of their psychometric properties--sensitivity, reliability, and content, criterion, construct, and face validity. Some test taxonomies are presented. Standardization is also discussed with reference to the reaction time, mathematical processing, memory search, spatial processing, unstable tracking, verbal processing, and dual task tests used in the AGARD STRES battery. Some comments on measurement strengths and appropriate study designs and methods are included.
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Affiliation(s)
- A Wetherell
- Chemical and Biological Defence Establishment, Porton Down, Salisbury, United Kingdom
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19
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Cohen RM, Gross M, Semple WE, Nordahl TE, Sunderland T. The metabolic brain pattern of young subjects given scopolamine. Exp Brain Res 1994; 100:133-43. [PMID: 7813641 DOI: 10.1007/bf00227285] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of an intravenous dose of 0.5 mg of scopolamine on the functional brain activity of normal subjects performing auditory discrimination (CPT) was determined in two independent positron emission tomography studies with [18F] 2-fluoro-deoxyglucose. In the first preliminary study, the most significant effect found was a reduction in the functional activity of the thalamus. In the second "hypothesis-testing" study, an equally prominent effect on thalamic functional activity was seen. Because the second study was performed on a high-resolution scanner with improved methodology, we re-examined scopolamine's effects on those brain regions established as determinants of CPT. Of the regions affected, the reduction in cingulate and the increase in basal ganglia metabolic rates were the most notable. We concluded that scopolamine's effects on the functions of thalamic, cingulate and basal ganglia are the likely causes of scopolamine's well-described attention-altering properties. Alterations in these same brain structures could be responsible for scopolamine's effects on other cognitive functions, e.g., memory. Alternatively, scopolamine's effects on other brain structures such as the hippocampus and frontal cortex could underlie scopolamine's effects on these other cognitive functions. Studies of scopolamine's regional metabolic effects in subjects performing these other cognitive tasks at more than a single dose and at more than one post-drug time are needed to discriminate between these two possibilities.
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Affiliation(s)
- R M Cohen
- Clinical Brain Imaging Section, NIMH, Bethesda, MD 20892-1000
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Sarter M. Neuronal mechanisms of the attentional dysfunctions in senile dementia and schizophrenia: two sides of the same coin? Psychopharmacology (Berl) 1994; 114:539-50. [PMID: 7855215 DOI: 10.1007/bf02244983] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Deficits in early stages of information processing, specifically the inability to "disattend" irrelevant stimuli and to selectively allocate processing resources (i.e., hyperattention), have been associated with the development of psychotic symptoms. Opposite deficits, i.e., the failure to attend and select stimuli, and to divide attention (i.e., hypoattention), represent a major variable in the development of dementia. The hypothesis that hyperattention and hypoattention are mediated via cortical cholinergic hyperactivity and hypoactivity, respectively, is discussed. Several lines of evidence support the role of cholinergic hyperactivity in the development of psychotic symptoms, including the therapeutic effects of anticholinergic drugs in schizophrenic patients, the psychotic effects of chronic exposure to irreversible cholinesterase inhibitors, and the worsening of psychotic symptoms as a result of the treatment with cholinomimetic compounds. The potent impairments of attentional abilities as a result of the administration of muscarinic antagonists in intact subjects, and the attentional effects of cholinomimetic compounds in demented patients are two examples of the evidence that supports the role of cholinergic hypofunction in the cognitive impairments of dementia. A neuronal model of dopamine-GABAergic modulation of cortical acetylcholine is proposed on the basis of evidence indicating that nucleus accumbens dopamine, via a GABAergic pathway to the substantia innominata of the basal forebrain, modulates cortical acetylcholine release. The available evidence confirms several predictions derived from this model, including the dopaminergic regulation of cortical acetylcholine (ACh) release, the bidirectional modulation of this release by benzodiazepine receptor (BZR) agonists and inverse agonists, and the antipsychotic effects of BZR agonists. Bidirectional deviations in the activity of cortical cholinergic inputs are hypothesized to represent a major neuronal substrate of the attentional dysfunctions associated with, or even underlying, the development of psychotic symptoms and dementia.
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Affiliation(s)
- M Sarter
- Ohio State University, Department of Psychology, Columbus 43210
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21
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Abstract
This paper reviews the literature on the effect of cholinergic blockade on human information processing, within the context of current debate concerning the relationship between deficits in attention and memory tasks. It questions whether we are making the most of the tools available to us and the opportunities there are to explore not only the neurochemical correlates of psychological function, but also the cognitive models on which the psychopharmacological research feeds. Current theoretical issues within cognitive psychology are discussed, and the drug studies are re-evaluated in terms of the resource model of information processing, which focuses on issues of automaticity of processes, and resource availability, rather than modular dissociations between attention and memory.
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Affiliation(s)
- J Rusted
- Laboratory of Experimental Psychology, University of Sussex, Falmer, Sussex BN1 9QG, UK
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22
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Callahan MJ, Kinsora JJ, Harbaugh RE, Reeder TM, Davis RE. Continuous ICV infusion of scopolamine impairs sustained attention of rhesus monkeys. Neurobiol Aging 1993; 14:147-51. [PMID: 8487917 DOI: 10.1016/0197-4580(93)90090-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Systemic administration of anticholinergic agents impairs cognitive performance in animals and man. The anticholinergic, scopolamine, has profound effects on peripheral and central cholinergic function, making interpretation of its effects on cognitive performance difficult. To circumvent this problem, scopolamine was administered directly to the central nervous system of rhesus monkeys using a subcutaneously implanted infusion pump connected to a cannulae directed toward the right lateral ventricle. Intracerebroventricular (ICV) infusion of scopolamine (0.004, 0.012, 12.5, and 40.0 micrograms/kg/h) produced a dose-dependent decrease in the number of responses on a continuous performance task. Response decrements produced by scopolamine were seen mainly during the last half of the test session and at short stimulus durations. These data suggest that scopolamine produces a deficit in sustained attention or slowing of information processing that is mediated through direct central cholinergic blockade in the rhesus monkey.
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Affiliation(s)
- M J Callahan
- Parke-Davis Pharmaceutical Research Division, Warner-Lambert Company, Ann Arbor, MI 48105
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23
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Zacny JP, Lichtor JL, Binstock W, Coalson DW, Cutter T, Flemming DC, Glosten B. Subjective, behavioral and physiological responses to intravenous meperidine in healthy volunteers. Psychopharmacology (Berl) 1993; 111:306-14. [PMID: 7870968 DOI: 10.1007/bf02244946] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Meperidine is a mu opiate agonist that is frequently used to treat pain. We examined in healthy volunteers (N = 10) the effects of intravenous meperidine (0, 0.25, 0.5, and 1.0 mg/kg) on mood and psychomotor performance. A randomized, placebo-controlled, crossover design was used in which subjects were injected with meperidine or saline in a double-blind fashion. Subjects completed several subjective effects questionnaires commonly used in abuse liability testing studies before drug injection and at periodic intervals for up to 5 h after drug injection. Subjects also completed several psychomotor tests. Meperidine produced a constellation of subjective effects in a dose-related fashion, including increases in ratings of "sedated," "coasting or spaced out" and "feel drug effect" ratings. Many of the drug's subjective effects persisted up to 4 or 5 h after administration of the 1.0 mg/kg dose. Drug liking ratings assessed on a visual analog scale were increased after meperidine injection in about half of the subjects (P = 0.09). Eye-hand coordination was affected slightly by meperidine but other indices of psychomotor functioning were unaffected. Miosis increased in a dose-related fashion. Other physiological parameters, such as vital signs, were not affected by meperidine. We conclude that meperidine in healthy volunteers has robust and long-lasting effects on mood, but may have weaker effects on psychomotor performance.
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Affiliation(s)
- J P Zacny
- Department of Anesthesia and Critical Care, Pritzker School of Medicine, University of Chicago, Illinois 60637
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24
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Wesnes KA, Simpson PM, White L, Pinker S, Jertz G, Murphy M, Siegfried K. Cholinesterase inhibition in the scopolamine model of dementia. Ann N Y Acad Sci 1991; 640:268-71. [PMID: 1776749 DOI: 10.1111/j.1749-6632.1991.tb00231.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Scopolamine produces a satisfactory model of the attentional and secondary memory deficits seen in Alzheimer's disease (AD) that can be used to screen compounds for potential therapeutic usefulness. Physostigmine, which is known to enhance memory in AD, produced marked and widespread antagonism of the scopolamine-induced impairments, indicating the sensitivity of the model and establishing its relevance for the clinical situation. HP 029, a novel anticholinesterase, also exhibited widespread potency in the model, and in an international trial with patients with AD, it subsequently showed improvement on similar measures, demonstrating the predictive use of the scopolamine model.
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Affiliation(s)
- K A Wesnes
- Cognitive Drug Research, Reading, United Kingdom
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25
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Lines CR, Dawson C, Preston GC, Reich S, Foster C, Traub M. Memory and attention in patients with senile dementia of the Alzheimer type and in normal elderly subjects. J Clin Exp Neuropsychol 1991; 13:691-702. [PMID: 1955525 DOI: 10.1080/01688639108401083] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previous studies have shown that cholinergic blockade in normal subjects induces impairment of vigilance as well as memory deficits. In the present investigation we have examined the validity of this pharmacological model of dementia by administering a battery of cognitive tasks to patients with mild and moderate senile dementia of the Alzheimer type and to age-matched controls. In contrast to volunteers receiving scopolamine all the mildly demented patients, and half of those moderately affected, performed normally on tests of vigilance whilst exhibiting the expected memory deficits. These data suggest that the mechanism of memory loss in Alzheimer's disease may differ from that found in scopolamine-induced amnesia.
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Affiliation(s)
- C R Lines
- Merck Sharp and Dohme Neuroscience Research Centre, Harlow, U.K
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26
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Ferris FD, Kerr IG, Sone M, Marcuzzi M. Transdermal scopolamine use in the control of narcotic-induced nausea. J Pain Symptom Manage 1991; 6:389-93. [PMID: 1880439 DOI: 10.1016/0885-3924(91)90031-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Nausea affects from 40% to 70% of cancer patients who received narcotics to manage their pain. This occurs more frequently when they are ambulatory than when they are recumbent and may be the result of narcotic-enhanced labyrinthine sensitivity to motion. Scopolamine has previously been found to be an effective antiemetic for motion sickness. In a prospective pilot study, 9 (69%) of 13 cancer patients experienced rapid relief of their narcotic-induced nausea when they used Scopolamine Transderm-V patches alone. Only two patients experienced side effects with the scopolamine, and in one patient, the side effects may have been dose related. Although tolerance to the increased vestibular sensitivity may occur, this was not universal. Further prospective trials are necessary to establish whether transdermal scopolamine is useful in controlling the narcotic-induced nausea experienced by cancer patients.
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27
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Parrott AC, Roberts G. Smoking deprivation and cigarette reinstatement: effects upon visual attention. J Psychopharmacol 1991; 5:404-9. [PMID: 22282850 DOI: 10.1177/026988119100500435] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Twenty regular smokers ( > 15 cigarettes/day), were tested on a letter cancellation task, over four successive days. On one of the test days subjects were smoking deprived for > 12 h, while on the other days they were not nicotine deprived (smoking was allowed until 1 h before testing). The first letter cancellation test was given prior to smoking. Then one cigarette was smoked and a second letter cancellation test given. Performance was significantly impaired by nicotine deprivation, when assessed both by response time (p < 0.05) and target detection (p < 0.001). Cigarette smoking led to significant improvements in both speed and accuracy with the deprived smokers. However, this improved performance basically reflected a return to near baseline values. The performance of the non-deprived subjects remained largely unchanged. There was no evidence of performance differences between high, mid and low frequency letter targets. Each showed an accuracy reduction of about 5% during smoking deprivation, and returned to baseline following nicotine reinstatement. Thus, while sustained attention was significantly influenced by nicotine status, there was no evidence of altered attentional selectivity.
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Affiliation(s)
- A C Parrott
- Department of Psychology, Polytechnic of East London, London E15 4LZ, UK
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28
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Lines CR, Preston GC, Broks P, Dawson CE. The effects of scopolamine on retrieval from semantic memory. J Psychopharmacol 1991; 5:234-7. [PMID: 22282561 DOI: 10.1177/026988119100500309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of two doses of scopolamine (0.6 and 1.2 mg p.o.) on retrieval from semantic memory in normal young volunteers were examined using tests of verbal fluency and categorization latency. A visual contrast sensitivity test, which has previously shown a scopolamine-induced impairment at these doses (Broks et al., 1988), was also administered. In agreement with the work of Dunne (1990) and others, no evidence for a scopolamine deficit in semantic retrieval was found; in fact scopolamine improved letter fluency. However, scopolamine did produce the expected decrease in visual contrast sensitivity. The doses of scopolamine used here have also been shown to impair learning and attention (Broks et al., 1988). It is possible that earlier studies which found a scopolamine deficit on semantic retrieval, did so because they used elderly subjects and/or large drug doses.
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Affiliation(s)
- C R Lines
- Department of Clinical Neuroscience, Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, UK
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29
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Liberati AM, Biagini S, Perticoni G, Ricci S, D'Alessandro P, Senatore M, Cinieri S. Electrophysiological and neuropsychological functions in patients treated with interferon-beta. JOURNAL OF INTERFERON RESEARCH 1990; 10:613-9. [PMID: 2086673 DOI: 10.1089/jir.1990.10.613] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The neurotoxicity of interferon-beta (IFN-beta) was assessed by performing electrophysiological examinations and neuropsychological tests on 22 patients with malignant hematological diseases before, during, and after IFN-beta treatment. IFN-beta (6 x 10(6) IU/m2) was infused i.v. for 6 h daily for 7 days on alternate weeks for a total of three cycles (induction therapy) and was then continued at the same dose, twice a week, for an additional 24 weeks (maintenance therapy). Twenty-one of the 22 patients were evaluable. There were no significant changes in EEGs, visual evoked potentials, sensory conduction central time or motor nerve conduction velocity of two long nerves in the 15-19 patients studied before and after induction therapy, nor in the 6-8 patients investigated at the end of maintenance therapy. Neuropsychological monitoring failed to disclose any IFN-induced deterioration in 21 patients tested before and at the end of induction therapy or in the 10 patients who were also studied at the end of maintenance therapy. Despite certain limitations in the patient follow-up, the results underline the good general tolerance of IFN-beta.
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Affiliation(s)
- A M Liberati
- First Department of Internal Medicine, Perugia University, Italy
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30
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31
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Friedman H, Seckman C, Stubbs C, Oster H, Royer G. Multiple-Dose Safety Study of Ibuprofen/Codeine and Aspirin/Codeine Combinations. J Clin Pharmacol 1990. [DOI: 10.1002/j.1552-4604.1990.tb03440.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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32
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Wesnes K, Anand R, Simpson P, Christmas L. The use of a scopolamine model to study the potential nootropic effects of aniracetam and piracetam in healthy volunteers. J Psychopharmacol 1990; 4:219-32. [PMID: 22281851 DOI: 10.1177/026988119000400406] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study 26 healthy volunteers received scopolamine 0.7 mg subcutaneously on seven occasions at least a week apart. Cognitive efficiency was measured with a test battery before and 60 min following scopolamine on each occasion. Following this, over the seven occasions, a range of oral and intravenous dose regimens were administered including aniracetam 2 mg intravenously, 100 mg intravenously, 200 mg intravenously, 1500 mg per os and piracetam 2400 mg per os. On each session the test battery was then performed again at 120 and 200 min following scopolamine. The seven treatments were administered double- blind and the order was counterbalanced between volunteers over visits using a Latin Square design. At 60 min, scopolamine produced marked and significant decrements in all of the measures of memory and information processing. Aniracetam 1500 mg was able to sig nificantly antagonize decrements on both memory and information processing tasks. The other active treatments also produced significant effects, but for two these were equal to, and for two slightly above, the number which may have occurred by chance, and thus were questionable. Overall, the findings demonstrate that aniracetam 1500 mg can antagonize cognitive decrements produced by cholinergic blockade in healthy volunteers, and suggest that the drug possesses nootropic properties.
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Affiliation(s)
- K Wesnes
- Cognitive Drug Research, 13 The Grove, Reading RG1 4RB, UK
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33
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Parrott AC, Winder G. Nicotine chewing gum (2 mg, 4 mg) and cigarette smoking: comparative effects upon vigilance and heart rate. Psychopharmacology (Berl) 1989; 97:257-61. [PMID: 2498936 DOI: 10.1007/bf00442260] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Sixteen male smokers, abstinent the morning before testing, were assessed under four conditions: placebo chewing gum, 2 mg nicotine chewing gum, 4 mg nicotine gum, and cigarette smoking. Placebo gum was administered in the cigarette condition, while sham smoking occurred in the gum conditions. Pre-drug administration and post-drug difference scores were calculated for each assessment measure: rapid visual information processing (RVIP), memory for new information, and heart rate. Nicotine raised heart rate in a significant monotonic dose-related manner (P less than 0.001): placebo +0.2; 2 mg gum +5.1; 4 mg gum +9.8; cigarette +17.5 bpm. Rapid visual information processing target detections were also significantly related to dose (P less than 0.01), with this increased vigilance significant under 4 mg nicotine gum and cigarette smoking. Memory task performance was not significantly affected. Self-reported feelings of alertness/energy were higher while smoking than under placebo or 4 mg gum. Complaints about the taste of the 4 mg nicotine gum were frequent.
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Affiliation(s)
- A C Parrott
- Department of Psychology, North East London Polytechnic, UK
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34
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Brazell C, Preston GC, Ward C, Lines CR, Traub M. The scopolamine model of dementia: chronic transdermal administration. J Psychopharmacol 1989; 3:76-82. [PMID: 22156502 DOI: 10.1177/026988118900300205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The transient impairments of memory produced by the muscarinic antagonist scopolamine have been adopted as a pharmacological model of Alzheimer-type dementia in normal volunteers. In this study we examined the effects of chronic (72 h) transdermal administration of scopolamine on memory, attention, sedation and visual function. The transdermal patches provided constant plasma levels of scopolamine for the duration of the study. Indices of the peripheral effects of scopolamine (visual near-point and pupil size) showed impairments that were sustained for 3 days. However, measures of sedation and memory revealed impairments that were maximal the day after patch application and which were no longer present 3 days after application. This pattern of results is discussed in relation to pharmacological modelling of Alzheimer's disease.
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Affiliation(s)
- C Brazell
- Neuroscience Research Centre, Merck, Sharp and Dohme, Terlings Park, Eastwick Road, Harlow, Essex, UK
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35
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Golding JF, Strong R, Pethybridge RJ. Time-course of effects of oral cinnarizine and hyoscine on task performance. J Psychopharmacol 1989; 3:187-97. [PMID: 22282908 DOI: 10.1177/026988118900300401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Investigations into antimotion sickness drugs fall into two main categories: efficacy ('benefits') and side-effects ('costs'). This study was of the second type. Oral cinnarizine (30 mg: normal dose; and 75 mg: 2.5 x normal dose) and placebo, were investigated using a battery of automated mental, motor, physiological and other tests in twelve young healthy male volunteers. The higher cinnarizine dose level was chosen to exaggerate effects and make it easier to track them. Oral hyoscine (1.2 mg: 2 x normal dose) was employed as a positive internal control. Side-effects were almost exclusively due to hyoscine whereas cinnarizine was almost free of significant effects even at the higher dose of 75 mg. Hyoscine impaired performance 1-3 hours postdrug, whereas the effects of cinnarizine occurred approximately 5-7 hours postdrug. This paralleled the slower time-course for the protective action of cinnarizine against motion sickness noted in earlier studies. These results, taken in conjunction with previous trials, suggest that oral cinnarizine would seem less likely than hyoscine to produce unwanted decrements in performance.
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Affiliation(s)
- J F Golding
- Institute of Naval Medicine, Alverstoke, Gosport, Hants PO12 2DL, UK
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36
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Frith CD, McGinty MA, Gergel I, Crow TJ. The effects of scopolamine and clonidine upon the performance and learning of a motor skill. Psychopharmacology (Berl) 1989; 98:120-5. [PMID: 2498955 DOI: 10.1007/bf00442017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Twenty-eight subjects practised a task involving procedural knowledge in which a moving target has to be followed for two 3-min sessions. They were then randomly allocated to receive an IV injection of 0.4 mg scopolamine, 0.15 mg clonidine or saline. General impairment due to both active treatments was seen 20 min later in significantly decreased tracking performance. Subjects then had to learn a mirror-reversed version of the tracking task. This involved acquiring novel procedural knowledge. Subjects who had either saline or clonidine treatment showed rapid temporary improvements and also considerable permanent learning. Subjects treated with scopolamine, however, showed only slow temporary improvement and little permanent improvement in their performance at this task. This result suggests that a normally functioning cholinergic system is necessary not only for an efficient working memory but also for the long term acquisition of some kinds of procedural knowledge.
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Affiliation(s)
- C D Frith
- Division of Psychiatry, Clinical Research Centre, Harrow, Midlesex, UK
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37
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Itoh S, Takashima A, Katsuura G. Preventive effect of cholecystokinin octapeptide on scopolamine-induced memory impairment in the rat. Drug Dev Res 1988. [DOI: 10.1002/ddr.430120106] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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