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Graf W, Pearson J, Appadoo D, Robertson E, Ennis C. The prediction of far-infrared spectra for molecular crystals of forensic interest – Phenylethylamine, ephedrine & pseudoephedrine. Forensic Chem 2020. [DOI: 10.1016/j.forc.2019.100204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ennis C, Auchettl R, Appadoo DRT, Robertson EG. The prediction of far-infrared spectra for planetary nitrile ices using periodic density functional theory with comparison to thin film experiments. Phys Chem Chem Phys 2018; 20:23593-23605. [DOI: 10.1039/c8cp04219e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The application of high accuracy periodic DFT calculations to replicate laboratory thin film spectra allowing the assignment of vibrational far-infrared modes in nitrile-bearing planetary ices.
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Affiliation(s)
- C. Ennis
- Department of Chemistry and Physics
- La Trobe Institute for Molecular Science
- La Trobe University
- Victoria
- Australia
| | - R. Auchettl
- Department of Chemistry and Physics
- La Trobe Institute for Molecular Science
- La Trobe University
- Victoria
- Australia
| | | | - E. G. Robertson
- Department of Chemistry and Physics
- La Trobe Institute for Molecular Science
- La Trobe University
- Victoria
- Australia
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Ennis C, Auchettl R, Ruzi M, Robertson EG. Infrared characterisation of acetonitrile and propionitrile aerosols under Titan's atmospheric conditions. Phys Chem Chem Phys 2017; 19:2915-2925. [DOI: 10.1039/c6cp08110j] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acetonitrile and propionitrile aerosols were generated under simulated Titan conditions where new insight into the ice morphology, particle size and formation/diffusion kinetics has been extracted by online infrared spectroscopy.
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Affiliation(s)
- C. Ennis
- Department of Chemistry and Physics
- La Trobe Institute for Molecular Science
- La Trobe University
- Victoria
- Australia
| | - R. Auchettl
- Department of Chemistry and Physics
- La Trobe Institute for Molecular Science
- La Trobe University
- Victoria
- Australia
| | - M. Ruzi
- Department of Chemistry and Physics
- La Trobe Institute for Molecular Science
- La Trobe University
- Victoria
- Australia
| | - E. G. Robertson
- Department of Chemistry and Physics
- La Trobe Institute for Molecular Science
- La Trobe University
- Victoria
- Australia
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Travers BG, Tromp DPM, Adluru N, Lange N, Destiche D, Ennis C, Nielsen JA, Froehlich AL, Prigge MBD, Fletcher PT, Anderson JS, Zielinski BA, Bigler ED, Lainhart JE, Alexander AL. Atypical development of white matter microstructure of the corpus callosum in males with autism: a longitudinal investigation. Mol Autism 2015; 6:15. [PMID: 25774283 PMCID: PMC4359536 DOI: 10.1186/s13229-015-0001-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Accepted: 01/26/2015] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The corpus callosum is the largest white matter structure in the brain, and it is the most consistently reported to be atypical in diffusion tensor imaging studies of autism spectrum disorder. In individuals with typical development, the corpus callosum is known to undergo a protracted development from childhood through young adulthood. However, no study has longitudinally examined the developmental trajectory of corpus callosum in autism past early childhood. METHODS The present study used a cohort sequential design over 9 years to examine age-related changes of the corpus callosum in 100 males with autism and 56 age-matched males with typical development from early childhood (when autism can first be reliably diagnosed) to mid-adulthood (after development of the corpus callosum has been completed) (3 to 41 years of age). RESULTS The group with autism demonstrated a different developmental trajectory of white matter microstructure in the anterior corpus callosum's (genu and body) fractional anisotropy, which suggests atypical brain maturation in these regions in autism. When analyses were broken down by age group, atypical developmental trajectories were present only in the youngest participants (10 years of age and younger). Significant main effects for group were found in terms of decreased fractional anisotropy across all three subregions of the corpus callosum (genu, body, and splenium) and increased mean diffusivity, radial diffusivity, and axial diffusivity in the posterior corpus callosum. CONCLUSIONS These longitudinal results suggest atypical early childhood development of the corpus callosum microstructure in autism that transitions into sustained group differences in adolescence and adulthood. This pattern of results provides longitudinal evidence consistent with a growing number of published studies and hypotheses regarding abnormal brain connectivity across the life span in autism.
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Affiliation(s)
- Brittany G Travers
- />Occupational Therapy Program, Department of Kinesiology, University of Wisconsin-Madison, Madison, WI USA
- />Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705 USA
| | - Do P M Tromp
- />Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705 USA
- />Department of Psychiatry, University of Wisconsin-Madison, Madison, WI USA
| | - Nagesh Adluru
- />Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705 USA
| | - Nicholas Lange
- />Department of Psychiatry, Harvard School of Medicine, Boston, MA USA
- />Neurostatistics Laboratory, McLean Hospital, Belmont, MA USA
| | - Dan Destiche
- />Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705 USA
| | - Chad Ennis
- />Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705 USA
| | - Jared A Nielsen
- />Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT USA
| | - Alyson L Froehlich
- />Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT USA
| | - Molly B D Prigge
- />Department of Radiology, University of Utah, Salt Lake City, UT USA
- />Department of Pediatrics, University of Utah and Primary Children’s Medical Center, Salt Lake City, UT USA
| | - P Thomas Fletcher
- />Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT USA
- />School of Computing, University of Utah, Salt Lake City, UT USA
| | - Jeffrey S Anderson
- />Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT USA
- />Department of Radiology, University of Utah, Salt Lake City, UT USA
| | - Brandon A Zielinski
- />Department of Pediatrics, University of Utah and Primary Children’s Medical Center, Salt Lake City, UT USA
- />Department of Neurology, University of Utah, Salt Lake City, UT USA
| | - Erin D Bigler
- />Department of Psychology, Brigham Young University, Provo, UT USA
- />Neuroscience Center, Brigham Young University, Provo, UT 84602 USA
| | - Janet E Lainhart
- />Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705 USA
- />Department of Psychiatry, University of Wisconsin-Madison, Madison, WI USA
| | - Andrew L Alexander
- />Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705 USA
- />Department of Psychiatry, University of Wisconsin-Madison, Madison, WI USA
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McMurray EM, Wallace IR, Ennis C, Hunter SJ, Atkinson AB, Bell PM. Effect of eplerenone on insulin action in essential hypertension: a randomised, controlled, crossover study. J Hum Hypertens 2014; 28:575-8. [DOI: 10.1038/jhh.2014.19] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 12/21/2013] [Accepted: 01/22/2014] [Indexed: 11/09/2022]
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Travers BG, Bigler ED, Tromp DPM, Adluru N, Froehlich AL, Ennis C, Lange N, Nielsen JA, Prigge MBD, Alexander AL, Lainhart JE. Longitudinal processing speed impairments in males with autism and the effects of white matter microstructure. Neuropsychologia 2014; 53:137-45. [PMID: 24269298 PMCID: PMC3946881 DOI: 10.1016/j.neuropsychologia.2013.11.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 11/12/2013] [Accepted: 11/14/2013] [Indexed: 11/24/2022]
Abstract
The present study used an accelerated longitudinal design to examine group differences and age-related changes in processing speed in 81 individuals with autism spectrum disorder (ASD) compared to 56 age-matched individuals with typical development (ages 6-39 years). Processing speed was assessed using the Wechsler Intelligence Scale for Children-3rd edition (WISC-III) and the Wechsler Adult Intelligence Scale-3rd edition (WAIS-III). Follow-up analyses examined processing speed subtest performance and relations between processing speed and white matter microstructure (as measured with diffusion tensor imaging [DTI] in a subset of these participants). After controlling for full scale IQ, the present results show that processing speed index standard scores were on average 12 points lower in the group with ASD compared to the group with typical development. There were, however, no significant group differences in standard score age-related changes within this age range. For subtest raw scores, the group with ASD demonstrated robustly slower processing speeds in the adult versions of the IQ test (i.e., WAIS-III) but not in the child versions (WISC-III), even though age-related changes were similar in both the ASD and typically developing groups. This pattern of results may reflect difficulties that become increasingly evident in ASD on more complex measures of processing speed. Finally, DTI measures of whole-brain white matter microstructure suggested that fractional anisotropy (but not mean diffusivity, radial diffusivity, or axial diffusivity) made significant but small-sized contributions to processing speed standard scores across our entire sample. Taken together, the present findings suggest that robust decreases in processing speed may be present in ASD, more pronounced in adulthood, and partially attributable to white matter microstructural integrity.
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Affiliation(s)
- Brittany G Travers
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705, USA.
| | - Erin D Bigler
- Department of Psychology and Neuroscience Center, Brigham Young University, Provo, UT 84602, USA; The Brain Institute of Utah, University of Utah, 36 South Wasatch Drive, Salt Lake City, UT 84112, USA; Department of Psychiatry, University of Utah, 501 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Do P M Tromp
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705, USA
| | - Nagesh Adluru
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705, USA
| | - Alyson L Froehlich
- Department of Radiology, University of Utah, 30 North 1900 East #1A071, Salt Lake City, UT, USA
| | - Chad Ennis
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705, USA
| | - Nicholas Lange
- Departments of Psychiatry and Biostatistics, Harvard University, 677 Huntington Avenue, Boston, MA 02115, USA; Neurostatistics Laboratory, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
| | - Jared A Nielsen
- Interdepartmental Program in Neuroscience, University of Utah, 401 MREB, 20 North 1900 East, Salt Lake City, UT 84132, USA
| | - Molly B D Prigge
- Department of Radiology, University of Utah, 30 North 1900 East #1A071, Salt Lake City, UT, USA
| | - Andrew L Alexander
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705, USA; Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd., Madison, WI 53719, USA; Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 1005 Madison, WI 53705, USA
| | - Janet E Lainhart
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI 53705, USA
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Bolton DJ, Ennis C, McDowell D. Occurrence, virulence genes and antibiotic resistance of enteropathogenic Escherichia coli (EPEC) from twelve bovine farms in the north-east of Ireland. Zoonoses Public Health 2013; 61:149-56. [PMID: 23782867 DOI: 10.1111/zph.12058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Indexed: 02/01/2023]
Abstract
Cattle faecal samples (n = 480) were collected from a cluster of 12 farms, and PCR screened for the presence of the intimin gene (eae). Positive samples were cultured, and colonies were examined for the presence of eae and verocytotoxin (vtx) genes. Colonies which were positive for the intimin gene and negative for the verocytotoxin genes were further screened using PCR for a range of virulence factors including bfpA, espA, espB, tir ehxA, toxB, etpD, katP, saa, iha, lpfAO157/OI-141 and lpfAO157/OI-154. Of the 480 faecal samples, 5.8% (28/480) were PCR positive, and one isolate was obtained from each. All 28 isolates obtained were bfpA negative and therefore atypical EPEC (aEPEC). The serotypes detected included O2:H27, O8:H36, O15:H2, O49:H+, O84:H28, O105:H7 and O132:H34 but half of the isolates could not be serogrouped using currently available antisera. Twenty-two (79%) of the isolates carried the tir gene but only 25% were espB positive, and all other virulence genes tested for were scarce or absent. Several isolates showed intermediate resistance to ciprofloxacin, kanamycin, nalidixic acid, minocycline and tetracycline; full resistance to nalidixic acid or tetracycline with one isolate (O-:H8) displaying resistance to aminoglycosides (kanamycin and streptomycin), quinolones (nalidixic acid) and sulphonamides. This study provides further evidence that cattle are a potential source of aEPEC and add to the very limited data currently available on virulence genes and antibiotic resistance in this pathogenic E. coli group in animals.
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Affiliation(s)
- D J Bolton
- Department of Food Safety, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
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Travers BG, Adluru N, Ennis C, Tromp DPM, Destiche D, Doran S, Bigler ED, Lange N, Lainhart JE, Alexander AL. Diffusion tensor imaging in autism spectrum disorder: a review. Autism Res 2012; 5:289-313. [PMID: 22786754 PMCID: PMC3474893 DOI: 10.1002/aur.1243] [Citation(s) in RCA: 293] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 06/04/2012] [Indexed: 12/18/2022]
Abstract
White matter tracts of the brain allow neurons and neuronal networks to communicate and function with high efficiency. The aim of this review is to briefly introduce diffusion tensor imaging methods that examine white matter tracts and then to give an overview of the studies that have investigated white matter integrity in the brains of individuals with autism spectrum disorder (ASD). From the 48 studies we reviewed, persons with ASD tended to have decreased fractional anisotropy and increased mean diffusivity in white matter tracts spanning many regions of the brain but most consistently in regions such as the corpus callosum, cingulum, and aspects of the temporal lobe. This decrease in fractional anisotropy was often accompanied by increased radial diffusivity. Additionally, the review suggests possible atypical lateralization in some white matter tracts of the brain and a possible atypical developmental trajectory of white matter microstructure in persons with ASD. Clinical implications and future research directions are discussed.
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Affiliation(s)
- Brittany G Travers
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin, Madison, Wisconsin 53705, USA.
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Ennis C, McDowell D, Bolton DJ. The prevalence, distribution and characterization of Shiga toxin-producing Escherichia coli (STEC) serotypes and virulotypes from a cluster of bovine farms. J Appl Microbiol 2012; 113:1238-48. [PMID: 22862826 DOI: 10.1111/j.1365-2672.2012.05421.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 07/23/2012] [Accepted: 07/31/2012] [Indexed: 12/23/2022]
Abstract
AIMS To assess the prevalence of Shiga toxin-producing Escherichia coli (STEC) on a cluster of twelve beef farms in the north-east of Ireland. METHODS AND RESULTS Samples were screened for stx1 and stx2 using PCR. Positive samples were enriched in mTSB and STEC O157 isolated using immunomagnetic separation. Enrichment cultures were plated onto TBX agar to isolate non-O157 STEC. All isolates were serotyped and examined for a range of virulence genes and their antibiotic resistance phenotype determined. Eighty-four isolates of 33 different serotypes were cultured from the 13·7% of samples that were stx positive. The most prevalent serotype was O157:H7, the most common Shiga toxin was stx(2) , and a variety of virulence factor combinations was observed. O-:H-, O26:H11, O76:H34, O157:H7, O157:H16 and OX18:H+ also carried eaeA and hlyA genes. Twenty-nine per cent of strains were resistant to at least one antibiotic, 48% of which had multiple drug resistance (MDR) with O2:H32 displaying resistance to five antibiotics. CONCLUSIONS The ubiquitous nature of STEC on beef farms, the detection of stx(+) eaeA(+) hlyA(+) in the serotypes O-:H-, O157:H16 and OX18:H+ in addition to O157:H7 and O26:H11 and the widespread distribution of antibiotic resistance are of public health concern as new virulent STEC strains are emerging. SIGNIFICANCE AND IMPACT OF THE STUDY This study found no relationship between serotype and antibiotic resistance, therefore negating efforts to isolate serotypes using specific antibiotic supplemented media. The data presented provide further evidence of the emergence of new STEC virulotypes of potential public health significance.
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Affiliation(s)
- C Ennis
- Department of Food Safety, Teagasc Food Research Centre, Ashtown, Dublin, Ireland
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Ennis C. Elizabeth Christina Buchanan. West J Med 2011. [DOI: 10.1136/bmj.d7225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Au STB, Ennis C, Atkinson AB, McCance DR, Sheridan B, Bell PM. Rosiglitazone does not improve endothelial function in patients with essential hypertension. Ir J Med Sci 2002. [DOI: 10.1007/bf03170270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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McConnell EM, Bell PM, Ennis C, Hadden DR, McCance DR, Sheridan B, Atkinson AB. Effects of low-dose oral hydrocortisone replacement versus short-term reproduction of physiological serum cortisol concentrations on insulin action in adult-onset hypopituitarism. Clin Endocrinol (Oxf) 2002; 56:195-201. [PMID: 11874410 DOI: 10.1046/j.0300-0664.2001.01447.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Hypercortisolism is associated with impaired glucose tolerance and insulin resistance. For many years hydrocortisone 30 mg was the standard total daily replacement dose in adult hypopituitarism. The use of this conventional dose has now been shown to result in mild biochemical hypercortisolism and might contribute to the increased cardiovascular risk reported in hypopituitarism. The use of lower doses of hydrocortisone replacement therapy might prevent some of the adverse metabolic effects seen with conventional doses. PATIENTS In a randomized crossover study we assessed peripheral and hepatic insulin action in 15 ACTH-deficient patients with normal glucose tolerance on two occasions while receiving either a low-dose oral hydrocortisone replacement (LOR) therapy (15 mg at 0800, 5 mg at 1700) or a physiological hydrocortisone infusion (PHI), which achieved physiological serum cortisol concentrations. RESULTS Exogenous glucose infusion rates required to maintain euglycaemia were similar for the LOR and the PHI protocols (26.2 +/- 0.4 vs. 23.8 +/- 0.6 micromol/kg/min, respectively). Endogenous glucose production was also similar (12.0 +/- 2.5 vs. 11.6 +/- 2.4 micromol/kg/min, respectively) and in the post-absorptive state suppressed to a similar extent following insulin (4.5 +/- 2.0 vs. 5.1 +/- 3.1 micromol/kg/min). CONCLUSION Hydrocortisone replacement therapy at a dose of 15 mg with breakfast, 5 mg with evening meal does not increase peripheral or hepatic insulin resistance when compared to a hydrocortisone infusion designed to simulate physiological serum cortisol concentrations.
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Affiliation(s)
- E M McConnell
- Sir George E. Clark Metabolic Unit and Regional Endocrine Laboratory, Royal Victoria Hospital, Belfast, UK
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McConnell EM, Atkinson AB, Ennis C, Hadden DR, McCance DR, Sheridan B, Bell PM. The effects on insulin action in adult hypopituitarism of recombinant human GH therapy individually titrated for six months. J Clin Endocrinol Metab 2001; 86:5342-7. [PMID: 11701703 DOI: 10.1210/jcem.86.11.8044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
There is controversy about the effect of replacement GH on insulin action in adult hypopituitary patients. GH replacement calculated from weight leads to unacceptable side effects in some patients. Recent studies suggest it should be individually titrated in adults using serum IGF-I levels. We have assessed the effect of titrated GH replacement on peripheral and hepatic insulin action in 13 adult-onset hypopituitary patients (8 males and 5 females; ages 47 +/- 10 yr, mean duration of hypopituitarism 6 yr) with confirmed GH deficiency (GHD; maximum GH <5 mU/liter during insulin induced hypoglycemia), ACTH deficiency, and normal glucose tolerance. All patients were on stable hydrocortisone replacement (15 mg with breakfast, 5 mg with evening meal) for at least 2 months before the trial. Insulin action was assessed by the euglycemic hyperinsulinemic glucose clamp technique (1 mU/kg x min) before and after 6 months of GH therapy. GH was started at 0.8 IU sc daily and titrated monthly until the serum IGF-I increased to within 1-2 SD of the mean of normal age-matched controls. Body mass index did not change significantly during the 6 months of GH therapy. Fasting plasma glucose and HbA1c increased significantly after 6 months (5.2 +/- 0.0 vs. 5.5 +/- 0.0 mmol/liter, P < 0.0001, and 4.5 +/- 0.1 vs. 4.7 +/- 0.1%, P < 0.0005, respectively). There was no increase in fasting serum insulin (51.6 +/- 10.2 vs. 60.0 +/- 10.2 pmol/liter, P = 0.12). Exogenous glucose infusion rates required to maintain euglycemia were similar after GH (23.0 +/- 0.4 vs. 21.1 +/- 0.3 micromol/kg x min, P = 0.6). Endogenous glucose production in the fasting state was also unchanged following GH (11.8 +/- 0.7 vs.12.3 +/- 0.9 micromol/kg x min, P = 0.5) and suppressed to a similar extent following insulin (4.4 +/- 0.8 vs. 5.5 +/- 0.8 micromol/kg x min, P = 0.3). In summary, GH therapy for 6 months, with serum IGF-I maintained in the upper physiological range, increased fasting plasma glucose and HbA1c. There was no effect on peripheral or hepatic insulin sensitivity. Patients receiving GH therapy require long-term monitoring of glucose tolerance.
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Affiliation(s)
- E M McConnell
- Sir George E. Clark Metabolic Unit, Royal Victoria Hospital, Belfast, BT12 6BA, Northern Ireland, United Kingdom
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McSorley P, Young I, Bell P, Atkinson A, Ennis C, Sheridan B, Fee J, McCance D. Endothelial function and cardiovascular risk factors in young healthy adult offspring of parents with type 2 diabetes: Effect of vitamin E in a randomised double-blind placebo-controlled trial. Atherosclerosis 2000. [DOI: 10.1016/s0021-9150(00)80952-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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McSorley P, Bell P, Young I, Atkinson A, Ennis C, Sheridan B, Fee J, McCance D. Insulin action in young healthy adult offspring of parents with type 2 diabetes: Effect of vitamin E in a randomised double-blind placebo-controlled trial. Atherosclerosis 2000. [DOI: 10.1016/s0021-9150(00)80432-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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McSorley P, Lemon K, Young I, Bell P, Atkinson A, Ennis C, Sheridan B, Fee J, McCance D. Reduced resistance of low density lipoprotein to oxidation in young healthy adult offspring of parents with type 2 diabetes compared with controls. Atherosclerosis 2000. [DOI: 10.1016/s0021-9150(00)81168-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Dunlop J, Pass I, Ennis C. The cholecystokinin-B receptor antagonist L-740,093 produces an insurmountable antagonism of CCK-4 stimulated functional response in cells expressing the human CCK-B receptor. Neuropeptides 1998; 32:157-60. [PMID: 9639254 DOI: 10.1016/s0143-4179(98)90031-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A stable cell line expressing the human cholecystokinin-B receptor gene (hCCK-B.CHO) has been employed in an evaluation of the recently developed CCK-B receptor antagonist L-740,093. L-740,093 exhibited high affinity (IC50 0.49 nM) and selectivity (<50% displacement at CCK-A sites at 1 microM) for the human CCK-B receptor subtype as estimated from [125I]-CCK-8S displacement studies with membranes prepared from hCCK-B.CHO cells. The elevation of intracellular free Ca2+ in hCCK-B.CHO cells in response to stimulation with CCK-4 was used to evaluate the antagonist activity of L-740,093 in vitro. L-740,093 potently (IC50 5.4 nM) antagonized the 30 nM CCK-4-stimulated Ca2+ mobilization in hCCK-B.CHO cells. Further studies were performed to investigate the nature of the antagonist activity of L-740,093. When tested at 10 nM L-740,093 produced a modest rightward shift in the CCK-4 dose response curve, an effect which was accompanied by a small reduction (13%) in the maximum response to CCK-4. In the presence of 30 nM L-740,093 the maximum functional response to CCK-4 was further reduced by 45% indicating that L-740,093 behaves as an insurmountable antagonist of the human CCK-B receptor subtype.
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Affiliation(s)
- J Dunlop
- Biochemistry Laboratory, Wyeth Research Ltd, Maidenhead, UK.
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Dunlop J, Brammer N, Evans N, Ennis C. YM022 [(R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1,4- benzodiazepin-3-yl]-3-(3-methylphenyl)urea]: an irreversible cholecystokinin type-B receptor antagonist. Biochem Pharmacol 1997; 54:81-5. [PMID: 9296353 DOI: 10.1016/s0006-2952(97)00139-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A functional evaluation of the recently developed cholecystokinin type-B (CCK-B) receptor antagonist YM022 [(R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1,4-++ +benzodiazepin-3-yl]-3-(3-methylphenyl)urea] was undertaken in Chinese hamster ovary cells stably expressing the human CCK-B receptor gene (hCCK-B.CHO). YM022 exhibited high affinity and selectivity for the CCK-B receptor subtype as estimated from [125I]CCK8S displacement studies using membranes derived from hCCK-B.CHO and hCCK-A.CHO cells. Functional antagonist activity of YM022 was demonstrated employing CCK-4-stimulated Ca2+ mobilization in hCCK-B.CHO cells. In the presence of 30 nM YM022, the maximum effect of CCK-4 was suppressed to 48 +/- 11% of control, an effect that was accompanied by a modest rightward shift in the CCK-4 concentration-response curve. In contrast, the structurally similar CCK-B receptor antagonist L-365,260 [3R(+)-N-[2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepin -3-yl]-N'-(methylphenyl)urea; 30 nM-10 microM] produced progressive rightward shifts in the CCK-4 concentration-response curve, with no effect observed on the CCK-4 maximum response. Further characterization using the technique of microphysiometry revealed that the agonist activity of CCK-4 was not restored following washout after exposure to YM022. The antagonist activity of L-365,260, however, was found to be fully reversible in this system. Thus, YM022 behaves as an irreversible antagonist, whilst its structural analogue L-365,260 exhibits properties consistent with a competitive antagonist.
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Affiliation(s)
- J Dunlop
- Biochemistry Laboratory, Wyeth Research (UK) Ltd., Maidenhead.
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20
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Abstract
OBJECTIVE Although it is well established that hypercortisolism causes insulin resistance, the mechanisms responsible for impaired insulin action in Cushing's syndrome are unclear. This study investigated the contribution of the glucose/glucose-6-phosphate substrate cycle (G/G6P). PATIENTS Eight patients with Cushing's syndrome and seven control subjects were studied. All had normal fasting plasma glucose. DESIGN Insulin action was assessed using the euglycaemic glucose clamp at insulin infusion rates of 0.4 and 2.0 mU/kg/min combined with a simultaneous infusion of [2(3)H]- and [6(3)-H]-glucose. Glucose/ glucose-6-phosphate cycle activity was calculated as the difference in glucose turnover rates determined separately for [2(3)H]- and [6(3)H]-glucose by selective enzymatic detritiation. MEASUREMENTS AND RESULTS Exogenous glucose infusion rates required to maintain euglycaemia were significantly lower in Cushing's patients compared to controls, during the 0.4 mU/kg/min (7.8 +/- 1.2 vs 15.7 +/- 0.5 mumol/kg/min, P < 0.001) and the 2.0 mU/ kg/min insulin infusions (26.2 +/- 2.8 vs 51.5 +/- 3.5 mumol/ kg/min, P < 0.001). Endogenous glucose production was similar in both groups in the postabsorptive state (10.2 +/- 0.3 vs 10.8 +/- 0.4 mumol/kg/min, P = 0.50) and suppressed to a similar degree during hyperinsulinaemia. G/G6P cycle activity was markedly increased in the Cushing's group in the postabsorptive state (5.4 +/- 1.1 vs 2.0 +/- 0.5 mumol/kg/min, P = 0.028) and during the 0.4 mU/kg/min (3.2 +/- 0.6 vs 1.2 +/- 0.4 mumol/kg/min, P = 0.014) and 2.0 mU/kg/min insulin infusions (3.3 +/- 0.8 vs 1.1 +/- 0.5 mumol/kg/min, P = 0.049). CONCLUSIONS Patients with Cushing's syndrome show marked peripheral insulin resistance and enhanced hepatic G/G6P cycle activity. In the fasting state increased glucose/glucose-6-phosphate cycle activity may be a protective mechanism limiting hyperglycaemia. During hyperinsulinaemia G/G6P cycle activity was increased but insulin resistance was predominantly due to reduced peripheral glucose uptake.
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Affiliation(s)
- A P Heaney
- Sir George E. Clark Metabolic Unit, Royal Victoria Hospital, Belfast, Northern Ireland, UK
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21
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Khawaja X, Ennis C, Minchin MC. Pharmacological characterization of recombinant human 5-hydroxytryptamine1A receptors using a novel antagonist radioligand, [3H]WAY-100635. Life Sci 1997; 60:653-65. [PMID: 9048968 DOI: 10.1016/s0024-3205(96)00701-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The ligand binding characteristics of the recombinant human 5-HT1A receptor stably expressed in a Chinese Hamster Ovary (CHO) cell line are described using a selective agonist, [3H]8-OH-DPAT, and a novel antagonist radioligand, [3H]WAY-100635. The association of [3H]WAY-100635 was a time- and temperature-dependent process. Mn2+ > Ca2+ > Mg2+ reduced the specific [3H]WAY-100635 binding in a concentration-dependent manner, whereas Na+ and K+ were ineffective. Scatchard analyses revealed a homogeneous population of [3H]WAY-100635 recognition sites (Kd = 0.32 nM; Bmax = 162 fmol/mg of protein). Addition of divalent cations to the incubation medium produced a two-fold decrease in the binding affinity of [3H]WAY-100635 with no significant change in Bmax; GTP gamma S had no effect on Kd or Bmax parameters. [3H]WAY-100635 displayed a higher affinity (2-3 fold) for the 5-HT1A site when compared with [3H] 8-OH-DPAT binding under similar incubation conditions. Furthermore, [3H] 8-OH-DPAT labelled approximately 53-61% of total 5-HT1A sites recognised by [3H]WAY-100635. The competition binding profiles of [3H]WAY-100635 and [3H]8-OH-DPAT were highly correlated and consistent with the recognition of 5-HT1A receptors. Agonist competition curves with [3H]WAY-100635 were best-resolved into high- and low-affinity binding states, whereas partial agonist and antagonist curves were best-fit to one-site binding models. A significant correlation between the respective affinities of a range of agonists and antagonists at recombinant human and rodent hippocampal 5-HT1A binding sites (previously published) was also observed using [3H]WAY-100635 (r = 0.92; P < 0.0005) and [3H]8-OH-DPAT (r = 0.96; P < 0.0005). The availability of a novel, high-affinity antagonist radioligand, [3H]WAY-100635, will provide a useful tool for the further characterisation of 5-HT1A receptor pharmacology.
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Affiliation(s)
- X Khawaja
- Wyeth-Ayerst Research, Princeton, New Jersey 08543-8000, USA.
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22
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Abstract
A stable Chinese hamster ovary cell line expressing the human CCK-B receptor gene is described (hCCK-B.CHO). In radioligand binding experiments employing membranes derived from these cells the rank order of affinity estimated for a series of CCK receptor ligands (CCK-8S > CI988 > PD 135158 > pentagastrin > CCK-8NS > L-365,260 > CCK-4 > LY 288513 > devazepide > A71378 > lorglumide) was found to be in excellent agreement with CCK-B receptor pharmacology described in guinea-pig cortex. Functional coupling in hCCK-B.CHO cells was demonstrated using agonist stimulated mobilization of intracellular Ca2+, measured with the FURA-2 technique. The CCK-B receptor selective agonist CCK-4 stimulated the mobilization of intracellular Ca2+ with an estimated pEC50 value of 7.4. Consistent with CCK-B receptor pharmacology, the rank order of potency for antagonism of this response was observed to be PD 135158 > CI988 > L-365,260 >> devazepide > lorglumide. This cell line provides a powerful new tool for the evaluation and development of novel ligands acting at the human CCK-B receptor subtype.
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Affiliation(s)
- J Dunlop
- Biochemistry Laboratory, Wyeth Research (UK) Ltd, Taplow, Maidenhead.
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23
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Khawaja X, Evans N, Reilly Y, Ennis C, Minchin MC. Characterisation of the binding of [3H]WAY-100635, a novel 5-hydroxytryptamine1A receptor antagonist, to rat brain. J Neurochem 1995; 64:2716-26. [PMID: 7760052 DOI: 10.1046/j.1471-4159.1995.64062716.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The specific binding of [3H]WAY-100635 (N-[2-[4-(2-[O-methyl-3H]methoxyphenyl)-1-piperazinyl]ethyl]-N- 2-pyridinyl) cyclohexane carboxamide trihydrochloride) to rat hippocampal membrane preparations was time, temperature, and tissue concentration dependent. The rates of [3H]WAY-100635 association (k+1 = 0.069 +/- 0.015 nM-1 min-1) and dissociation (k-1 = 0.023 +/- 0.001 min-1) followed monoexponential kinetics. Saturation binding isotherms of [3H]WAY-100635 exhibited a single class of recognition site with an affinity of 0.37 +/- 0.051 nM and a maximal binding capacity (Bmax) of 312 +/- 12 fmol/mg of protein. The maximal number of binding sites labelled by [3H]WAY-100635 was approximately 36% higher compared with that of 8-hydroxy-2-(di-n-[3H]-propylamino) tetralin ([3H]8-OH-DPAT). The binding affinity of [3H]WAY-100635 was significantly lowered by the divalent cations CaCl2 (2.5-fold; p < 0.02) and MnCl2 (3.6-fold; p < 0.05), with no effect on Bmax. Guanyl nucleotides failed to influence the KD and Bmax parameters of [3H]WAY-100635 binding to 5-HT1A receptors. The pharmacological binding profile of [3H]WAY-100635 was closely correlated with that of [3H]8-OH-DPAT, which is consistent with the labelling of 5-hydroxytryptamine1A (5-HT1A) sites in rat hippocampus. [3H]WAY-100635 competition curves with 5-HT1A agonists and partial agonists were best resolved into high- and low-affinity binding components, whereas antagonists were best described by a one-site binding model. In the presence of 50 microM guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), competition curves for the antagonists remained unaltered, whereas the agonist and partial agonist curves were shifted to the right, reflecting an influence of G protein coupling on agonist versus antagonist binding to the 5-HT1A receptor. However, a residual (16 +/- 2%) high-affinity agonist binding component was still apparent in the presence of GTP gamma S, indicating the existence of GTP-insensitive sites.
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Affiliation(s)
- X Khawaja
- Department of Molecular Pharmacology, Wyeth Research (U.K.), Maidenhead, Berkshire, England
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24
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Dunlop J, Ennis C, Minchin MC, Rossiter J. The effect of 3 calmodulin antagonists on K(+)-stimulated neurotransmitter release from rat cortical slices. Biochem Soc Trans 1993; 21:416S. [PMID: 8131990 DOI: 10.1042/bst021416s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- J Dunlop
- Wyeth Research (U.K.) Ltd., Huntercombe Lane South, Taplow, Maidenhead, Berks
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25
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Abstract
Toxin I, a K+ channel blocker found in the venom of the black mamba snake with close sequence homology to the dendrotoxins, produced a concentration-related enhancement of both spontaneous and electrically evoked [3H]noradrenaline ([3H]NA) release from slices of rat cerebral cortex. The effect of toxin I on spontaneous [3H]NA release was blocked by tetrodotoxin and reduced in the presence of either CPP ((+-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid) or CNQX (6-cyano-7-nitroquinoxaline-2,3-dione) and was abolished in the presence of both antagonists. The results suggest that the enhancement of spontaneous [3H]NA release produced by toxin I may be mediated via the release of glutamate acting on both NMDA (N-methyl-D-aspartate) and non-NMDA receptors.
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Affiliation(s)
- C Ennis
- Wyeth Research (UK) Ltd., Taplow, Berks, UK
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26
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Dunlop J, Ennis C, White JF, Minchin MC. WAY 100252 inhibits evoked [3H]GABA release when tested against a number of release-inducing stimuli. Biochem Soc Trans 1993; 21:112S. [PMID: 8359368 DOI: 10.1042/bst021112s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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27
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Abstract
In slices of cerebral cortex from rat preloaded with [3H]GABA, muscimol produced a concentration-related inhibition of K(+)-evoked release of tritium with a pIC25 value of 7.80 +/- 0.39. Dimethylbarbituric acid (10 and 100 microM) and pentobarbitone (100 microM) significantly increased this value to 8.31 +/- 0.09, 9.91 +/- 0.21 and 8.50 +/- 0.21, respectively, whereas the steroid ligands alphaxalone (1 microM) and 5 beta-pregnane-3 alpha-ol-20-one (10 nM) had no significant effect. The 5 beta-pregnane-3 alpha-ol-20-one and 5 beta-pregnane-3,20-dione produced a concentration-related increase in K(+)-evoked release of tritium alone. These data suggest that the GABAA-like autoreceptor may be modulated by barbiturates but not by steroids and thus may be different from the postsynaptic GABAA receptor.
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Affiliation(s)
- C Ennis
- Wyeth Research (UK) Ltd, Berkshire, U.K
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28
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Hammond HK, Roth DA, Ford CE, Stamnas GW, Ziegler MG, Ennis C. Myocardial adrenergic denervation supersensitivity depends on a postreceptor mechanism not linked with increased cAMP production. Circulation 1992; 85:666-79. [PMID: 1310452 DOI: 10.1161/01.cir.85.2.666] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Two major hypotheses have been proposed to explain catecholamine supersensitivity after myocardial denervation, but neither sufficiently explains certain features of the phenomenon. In addition, a nonsurgical method for long-term myocardial adrenergic denervation is desirable but has not been accomplished or described with respect to catecholamine supersensitivity. METHODS AND RESULTS We have accomplished chronic myocardial adrenergic denervation by using 6-hydroxydopamine (6-OHDA). Sixteen weeks after 6-OHDA administration to newborn pigs, we found substantial myocardial adrenergic denervation associated with beta-adrenergic receptor (beta AR) downregulation. Despite decreased beta AR number, the dose of isoproterenol yielding 50% maximal heart rate change (ED50) was decreased, and heart rates during exercise showed increased responsiveness despite decreased circulating catecholamines. Thus, stimulation of fewer receptors yielded an increased response, implying improved signal transduction efficiency. Competitive binding studies with isoproterenol showed an increased proportion of beta AR with high-affinity binding in myocardial membranes from 6-OHDA pigs, suggesting that interaction between beta AR and cardiac G, may contribute to improved signal transduction efficiency. However, measures of adenylyl cyclase activity indicated marked reduction in beta AR-dependent and G2-dependent cAMP production in myocardial membranes from denervated animals despite a normal amount of cardiac Gs and decreased Gi. CONCLUSIONS We have demonstrated that substantial, long-term myocardial adrenergic denervation is possible using 6-OHDA. Denervation supersensitivity in this model does not depend on enhanced cAMP stimulation but rather depends on postreceptor elements in the beta AR-responsive pathway that may be independent of Gs-activated adenylyl cyclase activity. In this model of adrenergic denervation supersensitivity, beta-receptors, through Gs, may be linked to an alternative effector that drives heart rate responsiveness.
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Affiliation(s)
- H K Hammond
- Veterans Administration Medical Center, San Diego, CA 92161
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29
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Maisel AS, Michel MC, Insel PA, Ennis C, Ziegler MG, Phillips C. Pertussis toxin treatment of whole blood. A novel approach to assess G protein function in congestive heart failure. Circulation 1990; 81:1198-204. [PMID: 2156637 DOI: 10.1161/01.cir.81.4.1198] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This study was designed to assess G protein function in mononuclear leukocytes (MNL) of patients with congestive heart failure (CHF). MNL membranes were ADP-ribosylated in vitro in the presence of pertussis or cholera toxin. The amount of pertussis toxin substrates did not differ significantly between CHF patients (6,100 +/- 224 fmol/mg, n = 23) and age-matched healthy control subjects (5,812 +/- 972 fmol/mg protein, n = 19). Among the CHF patients, no differences were observed between those with idiopathic and ischemic CHF. The amount of cholera toxin substrates also did not differ significantly between CHF patients (7,522 +/- 1,405 fmol/mg protein, n = 11) and control subjects (5,654 +/- 707 fmol/mg protein, n = 14). Moreover, basal and isoproterenol- and prostaglandin E1-stimulated cyclic AMP (cAMP) accumulation in MNL was similar in control subjects and patients. To detect more subtle alterations of the cAMP-generating system, we incubated anticoagulated blood with 250-400 ng/ml pertussis toxin for 4 hours at 37 degrees C. This treatment completely ADP-ribosylated the MNL pertussis toxin substrates. Incubation with pertussis toxin did not change basal or prostaglandin E1-stimulated cAMP generation in MNL of control subjects, but it significantly enhanced stimulated generation (443 +/- 44 vs. 643 +/- 93 pmol/10(7) cells, p less than 0.025) in MNL of CHF patients. This enhancement was most pronounced in the most severely ill patients (New York Heart Association class IV) and correlated with plasma norepinephrine levels, another marker of CHF severity (r = 0.798, n = 11, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A S Maisel
- Department of Medicine, University of California, San Diego
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30
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Archibald JL, Bradley G, Opalko A, Ward TJ, White JC, Ennis C, Shepperson NB. Design of an antithrombotic-antihypertensive agent (Wy 27569). Synthesis and evaluation of a series of 2-heteroaryl-substituted dihydropyridines. J Med Chem 1990; 33:646-52. [PMID: 2299629 DOI: 10.1021/jm00164a028] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An approach to the design of potential combined antithrombotic-antihypertensive agents is described. A series of 1,4-dihydropyridines bearing a 1H-imidazol-1-yl or pyrid-3-yl substituted side chain in the 2-position were synthesized and tested for antihypertensive activity in spontaneously hypertensive rats and for inhibition of TXA2 synthetase in rabbit platelets, in vitro. 1,4-Dihydro-2-(1H-imidazol-1-ylmethyl)-6-methyl- 4-(3-nitrophenyl)pyridine-3,5-dicarboxylic acid 3-ethyl 5-methyl diester (1) was shown to be similar in potency to nitrendipine as an antihypertensive agent. Compound 1 inhibited TXA2 synthetase in rabbit and human platelets in vitro and reduced plasma TXB2 levels in rats at antihypertensive dose levels. The reductions in thromboxane production observed in vivo and in vitro were accompanied by enhanced levels of 6-KPGF1 alpha, reflecting diversion of the arachidonic acid cascade toward prostacyclin synthesis.
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Affiliation(s)
- J L Archibald
- Department of Chemistry, Wyeth Research UK, Maidenhead, Berkshire, England
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31
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Ennis C, Granger SE, Middlefell VC, Philpot ME, Shepperson NB. Pharmacologic effects of Wy 27569: a combined calcium channel blocker and thromboxane synthetase inhibitor. J Cardiovasc Pharmacol 1989; 13:511-9. [PMID: 2470986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Wy 27569 (1,4 dihydro-2-[imidazol-1-yl-methyl]-6-methyl-4- [3-nitrophenyl] pyridine-3,5, dicarboxylic acid 3-ethyl 5-methyl diester) is a combined calcium channel blocker and thromboxane synthetase inhibitor. This article reports the in vivo and in vitro pharmacological studies demonstrating these properties. Wy 27569 evoked rightward shifts and depressed the maximum of calcium dose response curves in potassium depolarised rat aortas [concentration required to inhibit the response by 50% (IC50) = 7.3 nM]. The calcium channel blocker nitrendipine exhibited a similar profile to, although more potent than, Wy 27569 (IC50 = 0.28 nM). Comparison of the data obtained in aortas with the effects of these compounds in electrically stimulated isolated ventricle strips (IC50 for Wy 27569 = 8.3 microM, IC50 for nitrendipine = 0.41 microM) suggests that Wy 27569, like nitrendipine, is a vascular selective calcium channel blocker. Wy 27569 and the thromboxane synthetase inhibitor dazoxiben inhibited the collagen-stimulated production of thromboxane B2 (TXB2, IC50 = 3.9 and 2.8 microM, respectively) and, over the same concentration range, enhanced the production of immunoreactive 6 keto prostaglandin F1 alpha (6 keto-PGF1 alpha) by human platelet rich plasma. Single doses of Wy 27569 (0.3-10 mg kg-1 p.o.) or dazoxiben (3-10 mg kg-1 p.o.) evoked a dose-related reduction of TXB2 and enhancement of immunoreactive 6 keto PGF1 alpha levels in rat plasma and serum. Nitrendipine (0.3-10 mg kg-1 p.o.) had no significant effect on either eicosanoid.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C Ennis
- Wyeth Laboratories, Taplow, Berks, England
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32
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Abstract
The effects of various benzodiazepine receptor ligands on the GABA autoreceptor have been studied in slices of cerebral cortex of the rat. The GABAA receptor agonist muscimol inhibited the K+-stimulated release of [3H]GABA with a pIC25 of 7.65 +/- 0.11. This effect was antagonised by the GABAA receptor antagonist bicuculline, which had an IC50 of 0.36 +/- 0.03 microM. Small concentrations (less than 1 microM) of the benzodiazepine full agonist clonazepam did not significantly alter K+-evoked release of [3H]GABA but shifted the concentration-effect curve for muscimol to the left. This effect was blocked by the benzodiazepine antagonist flumazenil. By contrast, the benzodiazepine full inverse agonist methyl beta-carboline-3-carboxylate shifted the muscimol concentration-effect curve to the right and this too was blocked by flumazenil. The results suggest that the GABA autoreceptor in cortical slices from the rat is modulated by a benzodiazepine receptor.
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Affiliation(s)
- C Ennis
- Department of Biomedical Research, Wyeth Research Ltd, Berkshire, U.K
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Ennis C, Haroun F, Lattimer N. Can the effects of meptazinol on the guinea-pig isolated ileum be explained by inhibition of acetylcholinesterase? J Pharm Pharmacol 1986; 38:24-7. [PMID: 2869122 DOI: 10.1111/j.2042-7158.1986.tb04461.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It has previously been shown that there is a cholinergic component in the antinociceptive action of the opioid analgesic drug meptazinol. In the present study meptazinol was shown to be an inhibitor of acetylcholinesterase in-vitro with a potency one hundredth that of physostigmine. This activity was found to reside only in the (-)-enantiomer of meptazinol. The anticholinesterase activity of meptazinol may explain the increase in the size of the electrically-evoked contraction of the guinea-pig isolated ileum preparation since by using a long pulse width (5 ms) it was found that the (-)-enantiomer of meptazinol modified only the component of the response due to neuronally released acetylcholine and had no direct effect on the smooth muscle. This property of meptazinol may also be responsible for the cholinergic effects of the drug in-vivo.
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Ennis C, Stephens RJ. A comparison of the effects of meptazinol and morphine on the release of acetylcholine from slices of mouse cerebral cortex. Neuropharmacology 1984; 23:1431-3. [PMID: 6527745 DOI: 10.1016/0028-3908(84)90085-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Morphine and the new centrally-active analgesic agent, meptazinol, both increased the K+-evoked release of tritium from slices of mouse cortex preloaded with [3H]choline. The effect of both compounds was antagonised by naloxone whereas the response to meptazinol, but not that to morphine, was reduced in the presence of either scopolamine or tetrodotoxin. Oxotremorine produced a concentration-related inhibition of tritium release, presumably via an action on presynaptic muscarinic receptors, which was also blocked by scopolamine. These results suggest that there may be an indirect component in the action of meptazinol which may be related to a previous finding in which the antinociceptive response to meptazinol in the mouse was antagonised by both scopolamine and naloxone.
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Abstract
Clonidine inhibited the electrically-induced twitch response of the rabbit and rat isolated vas deferens preparations and also the K+-evoked release of [3H]noradrenaline from rat cortical slices. This effect of clonidine was antagonized competitively by yohimbine. Phentolamine inhibited the electrically-induced twitch response of the rabbit, but not the rat, vas deferens and in low concentrations (less than 0.1 microM) also inhibited the K+-evoked release of [3H]NA from rat cortical slices. These inhibitory effects of phentolamine were antagonized by yohimbine in a competitive manner but were not antagonized by indoramin, an alpha 1-adrenoceptor antagonist. In the rabbit vas deferens, the effects of phentolamine were shown not to be due to the stimulation of beta-, H1-, H2-, 5-HT- or muscarinic receptors. These results are consistent with the view that phentolamine can act as an agonist at presynaptic alpha 2-adrenoceptors in the rabbit vas deferens and rat cortex but not in the rat vas deferens.
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37
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Blurton PA, Broadhurst AM, Cross JA, Ennis C, Wood MD, Wyllie MG. Panuramine, a selective inhibitor of uptake of 5-hydroxytryptamine in the brain of the rat. Neuropharmacology 1984; 23:1049-52. [PMID: 6514142 DOI: 10.1016/0028-3908(84)90127-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The neurochemical profile of the novel inhibitor of uptake of 5-hydroxytryptamine (5-HT) panuramine (Wy 26002) has been investigated in the rat. In vitro, panuramine was found to be a potent and selective inhibitor of uptake of 5-HT with an IC50 of 22 +/- 4 nM. The IC50 for inhibition of uptake of noradrenaline was 848 nM and that for uptake of dopamine greater than 10 micron. Panuramine, in concentrations up to 10 micron did not displace the specific binding of either [3H]spiroperidol or [3H]5-HT and had no effect on the spontaneous or potassium-evoked release of 5-HT, suggesting that the compound had little effect on serotonergic transmission other than the inhibition of uptake of 5-HT. Panuramine also produced a dose-related antagonism of the depletion of 5-HT in brain induced by p-chloroamphetamine, confirming the ability of the drug to inhibit uptake of 5-HT in vivo.
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Ennis C. The release of 5-hydroxytryptamine in the occipital and frontal cortex is modulated by different subtypes of alpha-adrenoceptor. J Pharm Pharmacol 1983; 35:750-1. [PMID: 6139460 DOI: 10.1111/j.2042-7158.1983.tb02885.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
1 The potassium-evoked release of [3H]-noradrenaline from slices of rat occipital cortex and the potassium-evoked release of [3H]-5-hydroxytryptamine from slices of rat frontal cortex were measured using a superfusion system. 2 The rank order of potency for a number of alpha-adrenoceptor agonists was different for the two neuronal systems, clonidine and azepexole being the most potent inhibitors of noradrenaline release and methoxamine and phenylephrine being the most potent against 5-hydroxytryptamine release. 3 The rank order of potency for a series of alpha-adrenoceptor antagonists in reversing the inhibition of noradrenaline release produced by clonidine was: phentolamine greater than rauwolscine = yohimbine = corynanthine much greater than WB4101, whereas against methoxamine-inhibition of 5-hydroxytryptamine release the rank order of potency was: WB4101 greater than phentolamine greater than corynanthine greater than yohimbine greater than rauwolscine. 4 The results suggest that the alpha-adrenoceptors which modulate potassium-evoked 5-hydroxytryptamine release are not identical with the alpha 2-adrenoceptors which modulate potassium-evoked 5-hydroxytryptamine release are not identical with the alpha 2-adrenoceptors located on noradrenergic nerve terminals and may more closely resemble alpha 1-than alpha 2-adrenoceptors.
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Robbins TW, Watson BA, Gaskin M, Ennis C. Contrasting interactions of pipradrol, d-amphetamine, cocaine, cocaine analogues, apomorphine and other drugs with conditioned reinforcement. Psychopharmacology (Berl) 1983; 80:113-9. [PMID: 6136060 DOI: 10.1007/bf00427952] [Citation(s) in RCA: 143] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The effects of various psychomotor stimulant drugs and drugs outside this class were examined on the efficacy of stimuli previously paired with reinforcement or reward (conditioned reinforcers, CR) in controlling responding. Pipradrol (5-45 mumol/kg), d-amphetamine (1.25-15.0 mumol/kg), and the cocaine analogues WIN 35,428 (0.1-30.0 mumol/kg) and in one of two determinations WIN 35,065-2 (0.1-29.0 mumol/kg) all generally increased responding on a lever providing CR, but did not change or decreased responding on a lever providing no CR (NCR). Cocaine (5-125 mumol/kg) and chlordiazepoxide (3.75-60.0 mumol/kg) had no significant effects. Morphine (3.2-32.0 mumol/kg) and alpha-flupenthixol (0.02-2.0 mumol/kg) generally reduced responding on both levers. Apomorphine (0.1-1.0 mumol/kg) generally increased responding on both levers. Neurochemical data showed that d-amphetamine was generally more potent than pipradrol in its effects on in vitro monoamine uptake and release.
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Abstract
5-hydroxytryptamine (5-HT) (3 X 10(-9) to 10(-6) M) produced a concentration-related inhibition of potassium-evoked tritium release from slices of rat hypothalamus preloaded with [3H]-5-HT. The response to 5-HT was unaffected by the presence of yohimbine (10(-6) M), pimozide (10(-7) M), domperidone (10(-7) M) or tetrodotoxin (10(-7) M), indicating that the response was not mediated via alpha 1- or alpha 2-adrenoceptors or dopamine receptors and that the receptors that were involved were located directly on the 5-HT nerve terminal. The 5-HT antagonist metergoline (10(-8) to 3 X 10(-7) M) produced a parallel rightward shift in the concentration-effect curve to 5-HT with no reduction in the size of the maximum response. The pA10 value for metergoline was 6.82 and the slope of the Arunlakshana-Schild plot was not significantly different from 1.0 indicating that it was a competitive antagonist. Methiothepin produced a similar effect to metergoline whilst cyproheptadine and methysergide were less potent as antagonists of 5-HT and were not competitive. Cinanserin was inactive. Thus we have characterized the 5-HT autoreceptor in the rat hypothalamus using a classical pharmacological approach and found that it has more in common with the autoreceptor which we have previously identified in the raphe nuclei of the rat than it has with the 5-HT receptor located on dopamine neuroterminals in the striatum.
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Ennis C, Cox B. Inhibitory muscarinic receptors modulate the potassium-evoked release of [3H]serotonin from rat hypothalamic slices. Eur J Pharmacol 1982; 81:159-62. [PMID: 7117367 DOI: 10.1016/0014-2999(82)90617-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
The effect of a series of indoleamines on the potassium-evoked release of previously accumulated [3H]serotonin from slices of rat raphe nuclei has been studied. Indoleamine agonists produced a dose-related inhibition of potassium-evoked tritium release which was reversed by methiothepin, metergoline, mianserin and methysergide but not cyproheptadine or cinanserin. The relative order of antagonist potency for this effect was different from that obtained for the antagonism of indoleamine-induced inhibition of potassium-evoked tritium release from rat striatal slices previously loaded with [3H]-dopamine. The results show that the serotonin-autoreceptor located on cell bodies and dendrites in the raphe nucleus is different from the postsynaptic serotonin receptor located on dopamine nerve terminals in the striatum.
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Abstract
Tryptamine produced a concentration-related inhibition of potassium-evoked release of tritium from slices of rat hypothalamus preloaded with 3H-serotonin. This effect of tryptamine was blocked by a series of serotonin antagonists with a relative order of potency which suggested that tryptamine was acting on a post-junctional serotonin receptor. However, the response to tryptamine was also blocked by tetrodotoxin, indicating that tryptamine may be acting indirectly via the release of a second neurotransmitter. The finding that physostigmine enhanced, whilst atropine antagonised the effect of tryptamine suggests that the second neurotransmitter may be acetylcholine. This possibility is discussed.
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Abstract
The effect of a series of indoleamines on the potassium-evoked tritium release of previously accumulated [3H]dopamine from rat striatal slices has been investigated. The indoleamines 5-hydroxytryptamine, 5-methoxytryptamine, 5-methoxy-N,N'-dimethyltryptamine and tryptamine (10(-7) to 10(-5) M) all reduced potassium-evoked release of tritium, to a maximum of 50%. The uptake of [3H]dopamine was unaffected by these compounds. A series of 5-hydroxytryptamine antagonists were examined for their ability to reduce the inhibition of potassium-evoked tritium release induced by 5-methoxytryptamine. The relative order of antagonist potency obtained was methysergide greater than metergoline greater than methiothepin greater than cinanserin greater than cyproheptadine greater than mianserin, and was consistent with an action on 5-hydroxytryptamine receptors. It is concluded that there are inhibitory 5-hydroxytryptamine receptors located on the terminals of dopaminergic neurones in the striatum.
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Abstract
The effect of GABA on potassium-evoked tritium release from two sizes of ribbon of rat striatum previously loaded with [3H]dopamine was studied. GABA had no effect on the release of tritium from 100 x 100 mum ribbons but produced a dose-related enhancement of potassium-evoked tritium release from 250 x 250 mum ribbons. The enhancement was unaffected by the presence of bicuculline or picrotoxin but was antagonised by tetrodotoxin. The effect of GABA was not mimicked by the GABA agonists muscimol or baclofen. The possible involvement of an interneurone is discussed. From antagonist studies the neurotransmitter released by the postulated interneurone did not appear to be acetylcholine, 5-hydroxytryptamine, glycine, glutamate or enkephalin.
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Cox B, Ennis C, Foote G. Relative potency of some neuroleptics as antagonists at dopamine-receptors in vivo compared with their reported ability to displace haloperidol binding in vitro [proceedings]. Br J Pharmacol 1980; 68:172P. [PMID: 6101975 PMCID: PMC2044133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Abstract
1 The effect of dopamine on longitudinal muscle strips of the guinea-pig isolated gastro-oesophageal junction was compared with the response obtained to phenylephrine, isoprenaline and clonidine. Phenylephrine (5 x 10(-7) to 5 x 10(-5) M) produced a dose-related contraction, whilst dopamine (10(-6) to 10(-4) M) and isoprenaline (5 x 10(-7) to 2 x 10(-5) M) produced dose-related relaxations. Clonidine was ineffective in doses up to 10(-5) M. 5-Hydroxytryptamine (5-HT) produced a contraction. 2 Phenylephrine was antagonized by alpha 1-adrenoceptor antagonists but unaffected by beta-adrenoceptor antagonists, whilst the opposite was the case for isoprenaline. A mixture of alpha- and beta-adrenoceptor antagonists was required to inhibit completely dopamine-induced relaxations. 5-HT (3 x 10(-7) M) was specifically antagonized by methysergide (3 x 10(-6) M). 3 pA2 values for a range of alpha-adrenoceptor and dopamine receptor antagonists were determined against dopamine and phenylephrine. The relative order of potency of the antagonists was the same for both antagonists and was prazosin greater than spiroperidol greater than phentolamine greater than domperidone greater than haloperidol, with pimozide and metoclopramide being inactive. 4 Tyramine caused dose-related relaxations of the gastro-oesophageal strips which were susceptible to the same range of antagonists as dopamine. 5 Cocaine (6 x 10(-6) M) and desmethylimipramine (3 x 10(-7) M) reduced the relaxations induced by dopamine and tyramine but there were quantitative differences in the antagonism. 6 Tissue from reserpine pretreated guinea-pigs was insensitive to tyramine but the response to dopamine was only partly reduced. 7 Histological examination of the strips revealed the presence of smooth muscle but only a sparse adrenergic innervation. 8 The results suggest that dopamine acts partly indirectly and partly directly on postjunctional alpha- and beta-adrenoceptors. There is no evidence for an action on specific dopamine receptors.
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