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Walker JM, Lwin A, Tayebi N, LaMarca ME, Orvisky E, Sidransky E. Glucocerebrosidase mutation T369M appears to be another polymorphism. Clin Genet 2003; 63:237-8. [PMID: 12694238 DOI: 10.1034/j.1399-0004.2003.00055.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Vogel M, Anderson LJ, Holden S, Deanfield JE, Pennell DJ, Walker JM. Tissue Doppler echocardiography in patients with thalassaemia detects early myocardial dysfunction related to myocardial iron overload. Eur Heart J 2003; 24:113-9. [PMID: 12559943 DOI: 10.1016/s0195-668x(02)00381-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
AIMS To compare an echocardiographic method for detecting abnormal cardiac function before development of overt cardiomyopathy with a recently validated technique of quantifying myocardial iron load. METHODS AND RESULTS We examined thalassaemia patients whose myocardial iron load had been evaluated with magnetic resonance imaging (MRI). By tissue Doppler echocardiography, myocardial velocities were sampled continuously from base to apex in the RV and LV free wall, and the septum in 52 patients aged 29.2 (14.2-43.1) years and 52 age-matched controls. Ninety-six percent of patients had normal LV ejection fraction by MRI. Thirty-eight (73%) had abnormal iron loading of the myocardium, and 33 of those had regional wall motion abnormalities detected in the septum (n=29), LV (n=2), RV (n=1), and septum plus LV (n=1). The incidence of wall motion abnormalities was significantly higher (P<0.04) in patients with myocardial iron overload (87%) than in the 14 without (35%). Furthermore, myocardial iron overload was suggested by a low T2(*)(15.1+/-15.8 ms) in patients with wall motion abnormalities vs those with normal wall motion (T2(*): 30+/-19 ms) (P<0.007). CONCLUSIONS Wall motion abnormalities may represent an early sign of cardiac disease despite preserved global function. The regional abnormalities are related to iron overload and easily detectable with tissue Doppler echocardiography.
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Abstract
Cannabinoids have been used to treat pain for many centuries. However, only during the past several decades have rigorous scientific methods been applied to understand the mechanisms of cannabinoid action. Cannabinoid receptors were discovered in the late 1980s and have been found to mediate the effects of cannabinoids on the nervous system. Several endocannabinoids were subsequently identified. Many studies of cannabinoid analgesia in animals during the past century showed that cannabinoids block all types of pain studied. These effects were found to be due to the suppression of spinal and thalamic nociceptive neurons, independent of any actions on the motor systems. Spinal, supraspinal and peripheral sites of cannabinoid analgesia have been identified. Endocannabinoids are released upon electrical stimulation of the periaqueductal gray, and in response to inflammation in the extremities. These observations and others thus suggest that a natural function of cannabinoid receptors and their endogenous ligands is to regulate pain sensitivity. The therapeutic potential of cannabinoids remains an important topic for future investigations, with previous work suggesting utility in clinical studies of cancer and surgical pain. New modes of delivery and/or new compounds lacking the psychotropic properties of the standard cannabinoid ligands offer promise for cannabinoid therapeutics for pain.
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Orvisky E, Park JK, Parker A, Walker JM, Martin BM, Stubblefield BK, Uyama E, Tayebi N, Sidransky E. The identification of eight novel glucocerebrosidase (GBA) mutations in patients with Gaucher disease. Hum Mutat 2002; 19:458-9. [PMID: 11933202 DOI: 10.1002/humu.9024] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mutations in the gene encoding for the lysosomal enzyme glucocerebrosidase (GBA) result in Gaucher disease. In this study, seven novel missense mutations in the glucocerebrosidase gene (A136E, H162P, K198E, Y205C, F251L, Q350X and I402F) and a splice site mutation (IVS10+2T-->A) were identified by direct sequencing of three amplified segments of the glucocerebrosidase gene. Five of the novel mutations were found in patients with neuronopathic forms of Gaucher disease, two of which, K198E and F251L, appear to be associated with type 2 Gaucher disease.
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Abstract
Five major approaches have been employed to determine the role of endocannabinoids in pain modulation: (1) studies of various markers of endocannabinoid action aimed at determining whether the necessary cannabinoid biochemical machinery is present in those brain areas that control pain sensitivity; (2) administration of exogenous cannabinoids to determine whether endocannabinoid action at appropriate sites would lead to a loss of pain sensitivity; (3) administration of compounds that would affect endocannabinoid action such as antagonists and transport inhibitors to determine whether drug-induced preterbation of cannabinoid action would alter pain sensitivity; (4) studies of genetically altered animals aimed at determining whether pain responses or responses to cannabinergic drugs are altered; and (5) studies that measure the release of endocannabinoids. Converging evidence from each of these research areas indicates that endocannabinods function to control pain in parallel with endogenous opioids but via different mechanisms.
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Pitcher CJ, Hagen SI, Walker JM, Lum R, Mitchell BL, Maino VC, Axthelm MK, Picker LJ. Development and homeostasis of T cell memory in rhesus macaque. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:29-43. [PMID: 11751943 DOI: 10.4049/jimmunol.168.1.29] [Citation(s) in RCA: 413] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The rhesus macaque (RM) is a critical animal model for studies of viral pathogenesis and immunity, yet fundamental aspects of their cellular immune response remain poorly defined. One such deficiency is the lack of validated phenotypic signatures for their naive and memory T cell subsets, and the resultant unavailability of accurate information on their memory T cell development, homeostasis, and function. In this study, we report a phenotypic paradigm allowing definitive characterization of these subsets and their comprehensive functional analysis. Naive T cells are optimally delineated by their homogeneous CD95(low)CD28(high)beta(7) integrin(int) (CD4+) or CD95(low)CD28(int)CD11a(low) (CD8+) phenotypes. This subset 1) was present in blood and secondary lymph tissues, but not effector sites; 2) vastly predominated in the fetal/neonatal immune system, but rapidly diminished with postnatal age; 3) lacked IFN-gamma production capability, and specific responses to RM CMV; and 4) demonstrated low in vivo proliferative activity. CD4+ and CD8+ memory subsets were CD95(high), but otherwise phenotypically heterogeneous and included all IFN-gamma production, RM CMV-specific responses, effector site T cells, and demonstrated high in vivo proliferative activity ( approximately 10 times the naive subset). These analyses also revealed the RM "effector memory" subset within the overall memory population. This population, best defined by lack of CD28 expression, contained the majority of RM CMV-specific cells, was highly enriched in extralymphoid effector sites, and comprised an increasing proportion of total memory cells with age. The effector memory subset demonstrated similar in vivo proliferative activity and survival as CD28+ "central memory" T cells, consistent with independent homeostatic regulation.
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Anderson LJ, Holden S, Davis B, Prescott E, Charrier CC, Bunce NH, Firmin DN, Wonke B, Porter J, Walker JM, Pennell DJ. Cardiovascular T2-star (T2*) magnetic resonance for the early diagnosis of myocardial iron overload. Eur Heart J 2001; 22:2171-9. [PMID: 11913479 DOI: 10.1053/euhj.2001.2822] [Citation(s) in RCA: 1153] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AIMS To develop and validate a non-invasive method for measuring myocardial iron in order to allow diagnosis and treatment before overt cardiomyopathy and failure develops. METHODS AND RESULTS We have developed a new magnetic resonance T2-star (T2*) technique for the measurement of tissue iron, with validation to chemical estimation of iron in patients undergoing liver biopsy. To assess the clinical value of this technique, we subsequently correlated myocardial iron measured by this T2* technique with ventricular function in 106 patients with thalassaemia major. There was a significant, curvilinear, inverse correlation between iron concentration by biopsy and liver T2* (r=0.93, P<0.0001). Inter-study cardiac reproducibility was 5.0%. As myocardial iron increased, there was a progressive decline in ejection fraction (r=0.61, P<0.001). All patients with ventricular dysfunction had a myocardial T2* of <20 ms. There was no significant correlation between myocardial T2* and the conventional parameters of iron status, serum ferritin and liver iron. Multivariate analysis of clinical parameters to predict the requirement for cardiac medication identified myocardial T2* as the most significant variable (odds ratio 0.79, P<0.002). CONCLUSIONS Myocardial iron deposition can be reproducibly quantified using myocardial T2* and this is the most significant variable for predicting the need for ventricular dysfunction treatment. Myocardial iron content cannot be predicted from serum ferritin or liver iron, and conventional assessments of cardiac function can only detect those with advanced disease. Early intensification of iron chelation therapy, guided by this technique, should reduce mortality from this reversible cardiomyopathy.
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Huang SM, Bisogno T, Petros TJ, Chang SY, Zavitsanos PA, Zipkin RE, Sivakumar R, Coop A, Maeda DY, De Petrocellis L, Burstein S, Di Marzo V, Walker JM. Identification of a new class of molecules, the arachidonyl amino acids, and characterization of one member that inhibits pain. J Biol Chem 2001; 276:42639-44. [PMID: 11518719 DOI: 10.1074/jbc.m107351200] [Citation(s) in RCA: 276] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mammals, specific lipids and amino acids serve as crucial signaling molecules. In bacteria, conjugates of lipids and amino acids (referred to as lipoamino acids) have been identified and found to possess biological activity. Here, we report that mammals also produce lipoamino acids, specifically the arachidonyl amino acids. We show that the conjugate of arachidonic acid and glycine (N-arachidonylglycine (NAGly)) is present in bovine and rat brain as well as other tissues and that it suppresses tonic inflammatory pain. The biosynthesis of NAGly and its degradation by the enzyme fatty acid amide hydrolase can be observed in rat brain tissue. In addition to NAGly, bovine brain produces at least two other arachidonyl amino acids: N-arachidonyl gamma-aminobutyric acid (NAGABA) and N-arachidonylalanine. Like NAGly, NAGABA inhibits pain. These findings open the door to the identification of other members of this new class of biomolecules, which may be integral to pain regulation and a variety of functions in mammals.
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Bülbring E, Walker JM. Joshua Harold Burn: 6 March 1892-13 July 1981. BIOGRAPHICAL MEMOIRS OF FELLOWS OF THE ROYAL SOCIETY. ROYAL SOCIETY (GREAT BRITAIN) 2001; 30:45-89. [PMID: 11616006 DOI: 10.1098/rsbm.1984.0002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Joshua Harold Burn was born on 6 March 1892 in Barnard Castle, County Durham . He was fond of his birth place and was greatly interested in the history of the ancient town which had grown up around the castle, built by Bernard de Baliol (or Balliol) in the 12th century . Burn lived there until he went to Cambridge in 1909. He was the only child of John George Burn (1857-1932) and Mary Josephine Howson (1859-1937), who came fro m the Wycliffe family. Burn knew little about his father’s ancestry. However, he remembered his grandfather, Joshua Burn, vividly: ‘He must have been about 5 feet 10 or 11 inches. He was always upright in carriage and wore a black frock coat and trousers with a tall hat. He was an active member of the Wesleyan Church and for many years was a local preacher. At that time the villages surrounding Barnard Castle constituted a circuit and every chapel was visited every Sunday either by the Superintendent or the Second Minister or by a local preacher.’
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Ghanekar SA, Stranford SA, Ong JC, Walker JM, Maino VC, Levy JA. Decreased HIV-specific CD4 T cell proliferation in long-term HIV-infected individuals on antiretroviral therapy. AIDS 2001; 15:1885-7. [PMID: 11579254 DOI: 10.1097/00002030-200109280-00021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The effect of highly active antiretroviral therapy (HAART) on HIV-specific CD4 T cell proliferation in long-term HIV-infected individuals was studied. Subjects receiving treatment for over a year were compared with individuals not receiving therapy. The absolute number of HIV-specific memory CD4 T cells proliferating in response to HIV antigen was substantially higher in untreated subjects than in those on HAART. A decrease in HIV-specific memory CD4 T cells could explain the rebound in HIV replication after the termination of HAART.
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Quint LE, Bland PH, Walker JM, Kazerooni EA, Martinez FJ, Iannettoni MD, Bookstein FL. Diaphragmatic shape change after lung volume reduction surgery. J Thorac Imaging 2001; 16:149-55. [PMID: 11428413 DOI: 10.1097/00005382-200107000-00002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Diaphragmatic shape in normal patients was significantly different from shape in emphysema patients. Postoperative diaphragmatic shape in patients with good clinical outcome differed from preoperative shape and was similar to shape in normal patients. In patients with poor clinical outcome, surgery appeared to have little effect on diaphragm shape.
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Davis SJ, Bhoo SH, Durski AM, Walker JM, Vierstra RD. The heme-oxygenase family required for phytochrome chromophore biosynthesis is necessary for proper photomorphogenesis in higher plants. PLANT PHYSIOLOGY 2001; 126:656-69. [PMID: 11402195 PMCID: PMC111157 DOI: 10.1104/pp.126.2.656] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The committed step in the biosynthesis of the phytochrome chromophore phytochromobilin involves the oxidative cleavage of heme by a heme oxygenase (HO) to form biliverdin IXalpha. Through positional cloning of the photomorphogenic mutant hy1, the Arabidopsis HO (designated AtHO1) responsible for much of phytochromobilin synthesis recently was identified. Using the AtHO1 sequence, we identified families of HO genes in a number of plants that cluster into two subfamilies (HO1- and HO2-like). The tomato (Lycopersicon esculentum) yg-2 and Nicotiana plumbaginifolia pew1 photomorphogenic mutants are defective in specific HO genes. Phenotypic analysis of a T-DNA insertion mutant of Arabidopsis HO2 revealed that the second HO subfamily also contributes to phytochromobilin synthesis. Homozygous ho2-1 plants show decreased chlorophyll accumulation, reduced growth rate, accelerated flowering time, and reduced de-etiolation. A mixture of apo- and holo-phyA was detected in etiolated ho2-1 seedlings, suggesting that phytochromobilin is limiting in this mutant, even in the presence of functional AtHO1. The patterns of Arabidopsis HO1 and HO2 expression suggest that the products of both genes overlap temporally and spatially. Taken together, the family of HOs is important for phytochrome-mediated development in a number of plants and that each family member may uniquely contribute to the phytochromobilin pool needed to assemble holo-phytochromes.
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Bacon JP, Farney RJ, Jensen RL, Walker JM, Cloward TV. Nasal continuous positive airway pressure devices do not maintain the set pressure dynamically when tested under simulated clinical conditions. Chest 2000; 118:1441-9. [PMID: 11083699 DOI: 10.1378/chest.118.5.1441] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVES Nasal continuous positive airway pressure (CPAP) is standard therapy for obstructive sleep apnea syndrome. The effective nasal mask pressure may be adversely affected by factors that increase system resistance (eg, long tubing and/or water condensation) and by dynamic variables (breathing frequency [f] and tidal volume [VT]). The present study was conducted in order to assess the performance of CPAP machines throughout a range of simulated clinical conditions. DESIGN Four currently used CPAP machines were tested at settings of 5, 10, 15, and 20 cm H(2)O using a pulmonary waveform generator to produce VTs of 0.4, 0.8, and 1.2 L at frequencies of 10, 20, and 30 breaths/min. Machines were tested under five conditions: 6-foot and 12-foot tubing, with and without an in-line humidifier, and 12-foot tubing with humidifier and water condensation. MEASUREMENTS Maximum and minimum mask pressure measurements were obtained during five respiratory cycles for each dynamic variable under each of the five conditions and CPAP settings (180 experiments on each of four CPAP models). RESULTS Using typical clinical parameters (VT, 0.4 L and 0.8 L; f, 10 breaths/min and 20 breaths/min; and CPAP, 5 to 15 cm H(2)O), mask pressure consistently varied above and below the set point when additional tubing and/or a humidifier were added to the system (0.7 to 2.9 cm H(2)O below and 0.5 to 1.0 cm H(2)O above the set pressure). Water condensation caused large pressure deviations (inspiratory pressure ranged from 3.5 to 5.6 cm H(2)O below set pressure, and expiratory pressure ranged from 0.7 to 3.5 cm H(2)O above set pressure). CONCLUSIONS Therapy and compliance could be adversely affected because some CPAP machines in current use do not maintain constant continuous mask pressure when tested using simulated conditions, especially when water condenses in the tubing.
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Stygall J, Kong R, Walker JM, Hardman SM, Harrison MJ, Newman SP. Cerebral microembolism detected by transcranial Doppler during cardiac procedures. Stroke 2000; 31:2508-10. [PMID: 11022086 DOI: 10.1161/01.str.31.10.2508] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral embolism with clinical sequelae may rarely complicate cardioversion and cardiac catheterization. Transcranial Doppler sonography has recently been introduced to monitor microemboli entering the middle cerebral artery in cardiac and carotid surgery. We therefore used this technique to evaluate the risk of asymptomatic embolism during common cardiac procedures. METHODS Patients were monitored by transcranial Doppler while undergoing direct current cardioversion (n=15) and cardiac catheterization (n=17). RESULTS Microemboli were detected in all patients having cardiac catheterization but in only 1 patient after cardioversion. CONCLUSIONS Microembolism occurred frequently during cardiac catheterization and rarely during cardioversion. It is not yet known whether this has clinical relevance.
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Fenety PA, Putnam C, Walker JM. In-chair movement: validity, reliability and implications for measuring sitting discomfort. APPLIED ERGONOMICS 2000; 31:383-393. [PMID: 10975665 DOI: 10.1016/s0003-6870(00)00003-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Sitting discomfort is traditionally evaluated with subjective rating scales which are referenced to an objective correlate (e.g. sitting posture) measured on a static (i.e. non-continuous) basis. Since sitting discomfort is dynamic in nature, it requires continuous, objective measurement. We therefore adapted an interface pressure mat to continuously record in-chair movement (ICM) as an indirect measurement of sitting discomfort by tracking the center of pressure (COP) at the buttock-chair interface. Here we report on two phases in the development of the COP system: laboratory validity and field reliability. In the laboratory study we confirmed system validity by simultaneously tracking ICM with the mat and a force platform (r2 > 0.80) and by comparing subjects' COP movement with their gross trunk movements (r2 > 0.86). In our field study we used the intraclass correlation coefficient to establish a data sampling (i.e. selection) protocol that was reliable. We collected ICM data on seated telecommunications Directory Assistance operators during 2 h field tests. Results showed that using a minimum sampling time of 5 min and then averaging a series of 5 min samples of ICM was more reliable than single discrete samples. Using the averaging protocol, we also showed that ICM increased significantly over 2 h and that ICM did not differ between trials.
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Abstract
BACKGROUND The analysis of cytokine production is a valuable component of studies of immune response to stimulation such as pathogens, vaccines, and other immunological challenges. One highly sensitive method of cytokine evaluation involves three-color flow cytometric analysis of cytokine production in individual CD4(+) T cells. METHODS We present four methods to enhance the acquisition and analysis of cells secreting the cytokines interferon gamma (IFNgamma), tumor necrosis factor alpha (TNFalpha), interleukin-2 (IL-2), and interleukin-4 (IL-4). Using cytomegalovirus (CMV) as the antigenic model, titration and kinetic experiments were carried out in whole blood from CMV-seropositive donors. RESULTS CMV is most effective as a stimulating antigen when used at a dose of 5 microg/ml and for a period of at least 6 h, the first 2 h in the absence of 10 microg/ml Brefeldin A. This period of incubation can be made more convenient by the use of a "timed cooling" device, whereby the samples are automatically cooled and held at 4 degrees C at the end of incubation. Such timed cooling does not affect backgrounds or the proportion of responding cells. For certain samples, a high background can be reduced by adding fourth-color reagents. They identify and allow for elimination of monocytes and activated platelets, which contribute to false positive staining. CONCLUSIONS These optimizations make the assay both convenient for use in whole blood samples and highly reproducible (intra-assay variability is less than 10%; interassay variability is less than 25%).
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Walker JM. Student research projects--a response. PHYSIOTHERAPY RESEARCH INTERNATIONAL 2000; 4:308-9. [PMID: 10633532 DOI: 10.1002/pri.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sañudo-Peña MC, Romero J, Seale GE, Fernandez-Ruiz JJ, Walker JM. Activational role of cannabinoids on movement. Eur J Pharmacol 2000; 391:269-74. [PMID: 10729368 DOI: 10.1016/s0014-2999(00)00044-3] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cannabinoid's major effect on movement is hypoactivity. Nevertheless, a biphasic excitatory/inhibitory effect of cannabinoids on movement has been repeatedly acknowledged. However, the literature is lacking a detailed description of such an effect. In this study, we performed a dose-response study of the effects of Delta(9)-tetrahydrocannabinol on movement. Immediately after the administration of vehicle or a dose of Delta(9)-tetrahydrocannabinol (0.2, 0.5, 1, 1.5, 2, 2.5, 3, 4, or 5 mg/kg), the animal was placed in an activity monitor and observed for 1 h. Several parameters were recorded. The horizontal and vertical activities were measured as the number of photobeams broken between the photocells on the walls of an activity monitor. The number of wet dog shakes, scratches with hindpaw, mouth movements, forepaw flutters were also recorded, as was the amount of time in minutes that each subject spent grooming. The number of fecal boluses was recorded as an index of autonomic activity. Each animal was subsequently tested for catalepsy in the bar test. A triphasic effect was observed: low doses of the cannabinoid receptor agonist Delta(9)-tetrahydrocannabinol (0.2 mg/kg) decreased locomotor activity while higher doses (1-2 mg/kg) dose-dependently stimulated movement until catalepsy emerged (2.5 mg/kg) accompanied by decreases in activity.
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Sañudo-Peña MC, Tsou K, Romero J, Mackie K, Walker JM. Role of the superior colliculus in the motor effects of cannabinoids and dopamine. Brain Res 2000; 853:207-14. [PMID: 10640618 DOI: 10.1016/s0006-8993(99)02291-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We studied the cellular distribution of CB1 cannabinoid receptors in the superior colliculus of the rat using an antibody raised against the N-terminal of the receptor. The effect of unilateral cannabinoid receptor stimulation in the intermediate layers of the superior colliculus on rotational behavior in rats was also explored. The antibody against CB1 receptors outlined the crossed descending system of the superior colliculus (predorsal bundle output system) as well as the collicular commisure. The potent cannabinoid agonist CP55,940 (5 microgram/0.25 microliter) induced strong contralateral turning when microinjected unilaterally into the lateral intermediate layers of the superior colliculus. The levels of turning obtained with the intracollicular administration of the cannabinoid were comparable to the highest levels obtained with dopamine agonists in the basal ganglia. The D(2) dopamine agonist quinpirole or the D(1) dopamine agonist SKF82958 reversed this contralateral rotation but failed to affect motor behavior on their own. A new motor pathway for cannabinoids is discussed.
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Sañudo-Peña MC, Force M, Tsou K, McLemore G, Roberts L, Walker JM. Dopaminergic system does not play a major role in the precipitated cannabinoid withdrawal syndrome. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1999; 20:1121-4. [PMID: 11216447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
AIM To determine the dopaminergic system involvement in precipitated cannabinoid withdrawal syndrome. METHODS The dopamine D1 receptor antagonist SCH23390 or the dopamine D2 receptor antagonist sulpiride was administered to rats chronically treated with either delta 9-tetrahydrocannabinol (THC) or vehicle. Subjects were then injected with either SR141716A or vehicle and behavior was observed for 1 h. RESULTS Administration of the cannabinoid receptor antagonist SR141716A to animals chronically treated with THC as described by Tsou et al (1995) produced a profound withdrawal syndrome. Treatment with dopamine antagonists did not attenuate cannabinoid precipitated withdrawal syndrome in THC tolerant animals while the agonists increased the syndrome. CONCLUSION It is unlikely that the dopaminergic system plays a major role in mediating the behavioral aspects of the cannabinoid withdrawal syndrome.
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