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Doepker C, Lieberman HR, Smith AP, Peck JD, El-Sohemy A, Welsh BT. Caffeine: Friend or Foe? Annu Rev Food Sci Technol 2016; 7:117-37. [PMID: 26735800 DOI: 10.1146/annurev-food-041715-033243] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The debate on the safety of and regulatory approaches for caffeine continues among various stakeholders and regulatory authorities. This decision-making process comes with significant challenges, particularly when considering the complexities of the available scientific data, making the formulation of clear science-based regulatory guidance more difficult. To allow for discussions of a number of key issues, the North American Branch of the International Life Sciences Institute (ILSI) convened a panel of subject matter experts for a caffeine-focused session entitled "Caffeine: Friend or Foe?," which was held during the 2015 ILSI Annual Meeting. The panelists' expertise covered topics ranging from the natural occurrence of caffeine in plants and interindividual metabolism of caffeine in humans to specific behavioral, reproductive, and cardiovascular effects related to caffeine consumption. Each presentation highlighted the potential risks, benefits, and challenges that inform whether caffeine exposure warrants concern. This paper aims to summarize the key topics discussed during the session.
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Affiliation(s)
| | - Harris R Lieberman
- US Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760;
| | - Andrew Paul Smith
- Centre for Occupational and Health Psychology, School of Psychology, Cardiff University, Cardiff CF10 3AS, United Kingdom;
| | - Jennifer D Peck
- Department of Biostatistics & Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
| | - Ahmed El-Sohemy
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario M5S 3E2, Canada;
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2
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Ribeiro VS, Leitão AE, Ramalho JC, Lidon FC. Chemical characterization and antioxidant properties of a new coffee blend with cocoa, coffee silverskin and green coffee minimally processed. Food Res Int 2014. [DOI: 10.1016/j.foodres.2014.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Monti M, Edvinsson L, Ranklev E, Fletcher R. Methylxanthines reduce in vitro human overall platelet metabolism as measured by microcalorimetry. ACTA MEDICA SCANDINAVICA 2009; 220:185-8. [PMID: 3776694 DOI: 10.1111/j.0954-6820.1986.tb02748.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effect in vitro of caffeine, theophylline and enprofylline on overall platelet metabolism was investigated by a sensitive microcalorimetric method. Platelet heat production rate was found to be decreased significantly in the presence of any of the three methylxanthines in mM concentrations. Also lower caffeine concentration, as occurring during normal coffee intake, reduced platelet metabolism. These results show that, firstly, methylxanthines have a direct influence on platelet metabolism, and secondly, microcalorimetry can be used as a new and sensitive tool for investigating the influence of drugs on blood cell metabolism.
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Uzbay TI, Kayir H, Ceyhan M. Effects of tianeptine on onset time of pentylenetetrazole-induced seizures in mice: possible role of adenosine A1 receptors. Neuropsychopharmacology 2007; 32:412-6. [PMID: 16823386 DOI: 10.1038/sj.npp.1301143] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Depression is a common psychiatric problem in epileptic patients. Thus, it is important that an antidepressant agent has anticonvulsant activity. This study was organized to investigate the effects of tianeptine, an atypical antidepressant, on pentylenetetrazole (PTZ)-induced seizure in mice. A possible contribution of adenosine receptors was also evaluated. Adult male Swiss-Webster mice (25-35 g) were subjects. PTZ (80 mg/kg, i.p.) was injected to mice 30 min after tianeptine (2.5-80 mg/kg, i.p.) or saline administration. The onset times of 'first myoclonic jerk' (FMJ) and 'generalized clonic seizures' (GCS) were recorded. Duration of 600 s was taken as a cutoff time in calculation of the onset time of the seizures. To evaluate the contribution of adenosine receptors in the effect of tianeptine, a nonspecific adenosine receptor antagonist caffeine, a specific A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a specific A2A receptor antagonist 8-(3-chlorostyryl) caffeine (CSC) or their vehicles were administered to the mice 15 min before tianeptine (80 mg/kg) or saline treatments. Tianeptine (40 and 80 mg/kg) pretreatment significantly delayed the onset time of FMJ and GCS. Caffeine (10-60 mg/kg, i.p.) dose-dependently blocked the retarding effect of tianeptine (80 mg/kg) on the onset times of FMJ and GCS. DPCPX (20 mg/kg) but not CSC (1-8 mg/kg) blocked the effect of tianeptine (80 mg/kg) on FMJ. Our results suggest that tianeptine delayed the onset time of PTZ-induced seizures via adenosine A1 receptors in mice. Thus, this drug may be a useful choice for epileptic patients with depression.
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Affiliation(s)
- Tayfun I Uzbay
- Department of Medical Pharmacology, Psychopharmacology Research Unit, Gulhane Military Medical Academy, Ankara, Turkey.
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Casas M, Prat G, Robledo P, Barbanoj M, Kulisevsky J, Jané F. Methylxanthines reverse the adipsic and aphagic syndrome induced by bilateral 6-hydroxydopamine lesions of the nigrostriatal pathway in rats. Pharmacol Biochem Behav 2000; 66:257-63. [PMID: 10880677 DOI: 10.1016/s0091-3057(00)00189-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated whether methylxanthines (caffeine and theophylline) would restore food and water intake in rats made aphagic and adipsic by bilateral 6-hydroxydopamine lesions of the nigrostriatal bundle, and these results were compared with the effects of d-amphetamine, the dopamine D(1) agonist SKF 38393, and the D(2/3) agonist quinpirole. In a separate experiment, we investigated whether the selective D(1) antagonist, SCH 23390, or the selective D(2) antagonist, sulpiride, would prevent the caffeine-induced restoration of food and water intake in bilaterally 6-hydroxydopamine denervated rats. The results showed that caffeine, theophylline, and quinpirole significantly reversed the aphagia and adipsia observed in lesioned animals. SKF 38393 had no significant effects on water intake, while it significantly restored food intake at the highest dose used. In contrast, d-amphetamine had no significant effects on food or water intake. Results from the second experiment showed that sulpiride attenuated the caffeine-induced restoration of food and water intake in lesioned rats to a greater extent than did SCH 23390. These data suggest that methylxanthines may mediate their effects on food and water intake in bilateral 6-hydroxydopamine-lesioned rats through an action at the dopaminergic system.
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Affiliation(s)
- M Casas
- Laboratori de Neuropsicofarmacologia, Hospital de la Santa Creu i Sant Pau, Avgda. St. Antoni Ma Claret, 167, 08025 Barcelona, Spain
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Abstract
This review summarises current knowledge on adenosine receptors, an important G protein-coupled receptor. The four known adenosine receptor subtypes A1, A2A, A2B, and A3 are discussed with special reference to the opportunities for drug development.
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Affiliation(s)
- S A Poulsen
- Queensland Pharmaceutical Research Institute, Griffith University, Brisbane, Australia
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Hom YK, Bandyopadhyay GK, Levay-Young BK, Nandi S. Adenosine-mediated inhibition of casein production by mouse mammary glands in culture. J Cell Physiol 1996; 168:314-21. [PMID: 8707867 DOI: 10.1002/(sici)1097-4652(199608)168:2<314::aid-jcp10>3.0.co;2-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The present study was carried out to examine whether activation of adenosine receptors by adenosine analogues will affect casein production by mouse mammary epithelial cells. The morphogenesis and functions of epithelial tissue in the mammary gland are influenced by their surrounding adipocytes. Adipocytes are known to release adenosine into the extracellular fluid which can modulate cyclic-AMP levels in surrounding cells through binding to their adenosine receptors. To examine a possible paracrine effect of adenosine, the modulation of casein production in mammary explant culture and mammary epithelial cell (MEC) culture by adenosine receptor agonists has been investigated. We have observed that activation of the A1-adenosine receptor subtype in mammary tissue by an adenosine analogue (-)N6-(R-phenyl-isopropyl)-adenosine (PIA) raised cAMP levels. PIA and another adenosine receptor agonist, isobutylmethylxanthine (IBMX), inhibited casein accumulation both in explants and in MEC cultures in the presence of lactogenic hormones, which suggests that PIA or adenosine can act directly on the epithelial cells. This inhibition does not appear to be caused by elevation of cAMP levels or phosphodiesterase activity. The inhibition of intracellular casein accumulation by PIA and IBMX in explant cultures can be reversed via treatment of pertussis toxin which is known to ADP-ribosylate GTP-binding G alpha i-proteins, indicating that a Gi-protein-dependent pathway may be involved in this inhibition. The results also suggest that local accumulation of adenosine in the extracellular fluids of mammary glands is likely to inhibit the lactogenic response of mammary epithelial cells.
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Affiliation(s)
- Y K Hom
- Department of Anatomy, University of California, San Francisco 94143, USA
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Abstract
For two chronic intraperitoneal caffeine dose regimens (10 and 80 mg/kg per day), tolerance developed rapidly (2-3 days) to the stimulatory effects of caffeine on locomotor activity. However, surmountability of the tolerant activity rate levels by caffeine administration was dose dependent: Activity rate was restored fully by acute caffeine administration for the 10 mg/kg per day series, but not for the 80 mg/kg per day series. The extent of tolerance was also dose-dependent: Tolerance was incomplete for the low-dose daily caffeine series but complete for the high-dose series. Upon discontinuation of daily caffeine dosing, activity rate decreased to the original baseline levels for both chronic series. Caffeine tolerance and the quantification of its surmountability may be explained by the pharmacokinetics of caffeine and the upregulation of adenosine receptors.
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Affiliation(s)
- C E Lau
- Department of Psychology, Rutgers University, New Brunswick, NJ 08903, USA
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Abstract
Locomotor activity increase was a bitonic function of acute caffeine IP doses (2.5-40 mg/kg) in rats. When the schedule-induced polydipsic, orally self-administered dose of caffeine was increased over blocks of daily 3 h sessions from 9.3 to 36.5 mg/kg, postsession activity increased monotonically as a function of dose. The rate of tolerance development to the increase in locomotor activity produced by caffeine depended on the route of administration. Tolerance onset occurred on the fourth day of chronic IP doses, but remained incomplete after 21 doses. With the highest dose level of oral caffeine self-administration, tolerance developed on day 13, but remained incomplete even after 17 doses. Acute tolerance occurred for each of the IP doses, whereas a linear relation between locomotor activity and serum caffeine concentration was obtained after oral self-administration. There were two- to threefold higher locomotor activity AUCs(4 h) with oral caffeine at three dose levels compared to the activity AUCs(4 h) for IP doses.
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Affiliation(s)
- C E Lau
- Department of Psychology, Rutgers University, New Brunswick, NJ 08903
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Tuckey JA, Parry BR, McCall JL. Methylxanthines in surgery: a bright future? THE AUSTRALIAN AND NEW ZEALAND JOURNAL OF SURGERY 1992; 62:250-5. [PMID: 1550512 DOI: 10.1111/j.1445-2197.1992.tb07550.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Methylxanthines have been used in clinical practice for over 100 years, and although understanding of their mechanisms of action is growing their effects are not fully understood. Nevertheless the knowledge to date has brought about a general upsurge of interest in methylxanthines and the development of novel derivatives. Methylxanthines are poised to escape the confines of their traditional role as these agents are applied in novel ways to surgical illnesses such as septic shock, the adult respiratory distress syndrome, cancer cachexia and functional neutrophil disorders. Methylxanthines, alone or in combination with other compounds, may well become part of the surgeon's future stock-in-trade.
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Affiliation(s)
- J A Tuckey
- Department of Surgery, University of Otago, Dunedin, New Zealand
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Schwarzschild MA, Zigmond RE. Effects of peptides of the secretin-glucagon family and cyclic nucleotides on tyrosine hydroxylase activity in sympathetic nerve endings. J Neurochem 1991; 56:400-6. [PMID: 1703218 DOI: 10.1111/j.1471-4159.1991.tb08165.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Previous studies have shown that certain peptides of the secretin-glucagon family stimulate tyrosine hydroxylase activity in sympathetic neurons of the superior cervical ganglion and three of its end organs, i.e., the iris, pineal gland, and submaxillary gland. To determine whether a similar regulation occurs in other sympathetic neurons, the effects of two of these peptides, secretin and vasoactive intestinal peptide, were examined in the right cardiac ventricle of the rat, a tissue innervated primarily by the middle and inferior cervical ganglia. Both peptides stimulated tyrosine hydroxylase activity, measured in situ, in this tissue. In addition, several second messenger systems were investigated as possible mediators of this peptidergic stimulation of tyrosine hydroxylase activity in autonomic end organs. 8-Bromoadenosine 3',5'-cyclic monophosphate and forskolin elevated tyrosine hydroxylase activity in slices of both the right ventricle and the submaxillary gland. 8-Bromoguanosine 3',5'-cyclic monophosphate also stimulated tyrosine hydroxylase activity in both tissues, whereas nitroprusside stimulated activity only in the submaxillary slices. Furthermore, the phosphodiesterase inhibitors 3-isobutyl-1-methylxanthine and/or Ro 20-1724 potentiated the stimulation by secretin, as well as the stimulations by forskolin and nitroprusside. Phorbol 12,13-dibutyrate also stimulated tyrosine hydroxylase activity in cardiac and submaxillary slices; however, no potentiation of these effects was seen following addition of either phosphodiesterase inhibitor. These data, taken together with those of previous studies, suggest a role for a cyclic nucleotide, probably adenosine 3',5'-cyclic monophosphate, in the peptidergic stimulation of tyrosine hydroxylase activity in sympathetic nerve terminals.
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Affiliation(s)
- M A Schwarzschild
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts
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Schroeder H, Boyet S, Nehlig A. Effects of caffeine and doxapram perfusion on local cerebral glucose utilization in conscious rats. Eur J Pharmacol 1989; 167:245-54. [PMID: 2591477 DOI: 10.1016/0014-2999(89)90585-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The quantitative autoradiographic 2-[14C]deoxyglucose method was used to measure the effects of a continuous infusion of the respiratory stimulants, caffeine or doxapram, 18 mg/kg per h, on local cerebral glucose utilization in the adult male rat. Local cerebral glucose utilization was measured in 54 cerebral structures from different systems. Caffeine induced widespread increases in energy metabolism, resulting in a significant increase in glucose utilization in 25 structures out of the 54 studied. These increases were distributed within all systems studied, sensory, extrapyramidal motor, limbic and hypothalamic systems. In addition, caffeine induced a non-significant, 10-15%, increase in local cerebral glucose utilization in central respiratory areas. Doxapram infusion did not change the rates of glucose utilization in any of the structures. The rates of local cerebral glucose utilization were significantly lower after doxapram than after caffeine exposure in five cerebral areas, among which were three central respiratory areas. The results confirm the absence of side-effects of doxapram as compared to caffeine when used as respiratory stimulant, especially in neonates. These results also favor a preferentially central action of caffeine on respiratory areas and a more peripheral action of doxapram on chemoreceptors, at least at therapeutic levels.
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Wajda IJ, Banay-Schwartz M, Lajtha A. The effect of caffeine on some mouse brain free amino acid levels. Neurochem Res 1989; 14:317-20. [PMID: 2761666 DOI: 10.1007/bf01000033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Changes in free amino acids were examined in the central nervous system of mice treated with caffeine for three weeks. Caffeine was administered in the drinking water, and at the end of three weeks the level of caffeine in the cerebral cortex was 113 +/- 19 micrograms/g. When amino acid levels in cerebral hemispheres, midbrain, pons and medulla, and cerebellum were measured a significant increase in glutamine levels was found in all four regions. Glycine, alanine, serine, threonine, and GABA were significantly reduced in some regions. Caffeine appears to alter some of the metabolic or transport processes regulating amino acid pools in the brain. The decrease of GABA found in pons and medulla may contribute to the observed increase in reflex excitability after caffeine.
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Affiliation(s)
- I J Wajda
- Nathan S. Kline Institute for Psychiatric Research, Center for Neurochemistry, Ward's Island, New York 10035
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14
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Durcan MJ, Morgan PF. NECA-induced hypomotility in mice: evidence for a predominantly central site of action. Pharmacol Biochem Behav 1989; 32:487-90. [PMID: 2727008 DOI: 10.1016/0091-3057(89)90185-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The behavioral effects of four adenosine analogues (NECA, CHA, CPA and CV-1808) were investigated in mice using a holeboard test, which measures both directed exploration (head-dipping) and a locomotor activity. NECA, CHA and CPA showed significant dose-related reductions in all the holeboard measures (NECA much greater than CHA = CPA), whilst CV-1808 showed no significant effect on any of the measures over the dose range tested. In a subsequent experiment NECA-induced hypomotility was attenuated by the adenosine receptor antagonists, theophylline (which is both centrally and peripherally active) and, though to a lesser extent, by the adenosine receptor antagonist 8-(p-sulfophenyl)theophylline (8-pSPT), which poorly penetrates the blood-brain barrier. The results suggest that NECA-induced hypomotility may be predominantly mediated centrally since the centrally active antagonist was the most effective in reversing the effect, however, peripheral mechanisms may also play a role since equimolar concentrations of 8-pSPT elicit some reversal of NECA-induced hypomotility.
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Affiliation(s)
- M J Durcan
- Laboratory of Clinical Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD 20892
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Durcan MJ, Morgan PF. Time-course of the hypomotility effects of the adenosine analogues, cyclohexyladenosine and N-ethylcarboxamidoadenosine, in a holeboard test. J Psychopharmacol 1989; 3:175-9. [PMID: 22282902 DOI: 10.1177/026988118900300308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The time-course of the hypomotility effects of the adenosine analogues 5'-N- ethylcarboxamidoadenosine (NECA) and N(6)-cyclohexyladenosine (CHA) was investigated in a holeboard test. Behaviourally equipotent doses of both compounds given to independent groups of animals showed significant depression of both exploratory head-dipping and locomotor activity at the 9, 18 and 36 min time points after drug administration. No significant differences from control group values were detected at 72 or 144 min post-administration. Additionally, the effects of both analogues administered immediately before a holeboard test were examined by investigating four 2 min time bins over the 8 min test session. Significant drug x time bin interactions were detected: NECA and CHA both showed faster reductions in locomotor activity, and NECA more reduction in head-dipping, over the test as compared to control. However, no differences between NECA and CHA on test habituation were detected. The results of these experiments support the view that pharmacodynamic rather than phar macokinetic factors may be responsible for the different behavioural potencies of NECA and CHA.
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Affiliation(s)
- M J Durcan
- Laboratory of Clinical Studies, National Institute on Alcohol Abuse and Alcoholism, DICBR, Building 10, Room 3C 102, 9000 Rockville Pike, Bethesda, Maryland 20892, USA
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Staines WA, Yamamoto T, Dewar KM, Daddona PE, Geiger JD, Nagy JI. Distribution, morphology and habenular projections of adenosine deaminase-containing neurons in the septal area of rat. Brain Res 1988; 455:72-87. [PMID: 3046711 DOI: 10.1016/0006-8993(88)90116-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Adenosine deaminase (ADA) was localized within several types of neurons within the septum and in septal efferent projections to the habenula by immunohistochemical, biochemical, retrograde tracing and lesion methods. Numerous ADA-immunoreactive (ADA-IR) neurons were observed in the septofimbrial nucleus, the triangular septal nucleus and the bed nucleus of the anterior commissure, while considerably fewer numbers were seen in the lateral septal area. Based on their size, shape and dendritic features, 4 morphologically distinct types of ADA-IR neurons were recognized in these septal structures. In addition, fine, non-varicose, ADA-IR fibers appeared to emanate from the postcommissural cell groups and these coalesced within the stria medullaris, continued caudally within this fiber bundle, and gave rise to a dense field of very fine immunoreactive elements within a restricted zone of the dorsal half of the medial habenula. Comparisons of the habenular localization of ADA-IR and enkephalin-IR elements showed that fibers labelled for either ADA or enkephalin occupied distinct, non-overlapping regions within the dorsal half of the medial habenula. After injections of Fluoro-gold (FG) into the medial habenula, the majority of ADA-IR neurons in the septofimbrial nucleus, triangular septal nucleus, and the bed nucleus of the anterior commissure were retrogradely labelled with this fluorescent tracer, whereas no ADA-positive FG-labelled neurons were observed in the lateral septal region. Unilateral transections of the stria medullaris caused substantial depletions of ADA-immunoreactivity and reduced enzymatically determined ADA activity by up to 80% in the medial habenula on the lesioned compared with the contralateral control side. These results demonstrate that ADA-IR neurons in the septum are heterogeneously distributed and that populations of positive neurons within the postcommissural septal nuclei give rise to dense, focal projections to the medial habenula. These projections appear to be restricted to a portion of the medial habenula known to contain substance P-IR neurons and are subregionally segregated from enkephalin-positive septohabenular projections ending within this same portion. In addition to pointing out a unique capacity for adenosine catabolism within some septal neurons, possibly related to purinergic neuromodulation, the results indicate the utility of ADA-immunohistochemistry for the delineation of anatomical relationships between the septum and the medial habenula.
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Affiliation(s)
- W A Staines
- Department of Anatomy, University of Ottawa, Ont., Canada
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Steele J, McDougall G, Shadwick R. Trehalose efflux from cockroach fat body in vitro: Paradoxical effects of the corpus cardiacum and methylxanthines. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0020-1790(88)90010-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Affiliation(s)
- C H Ashton
- University Department of Pharmacological Sciences, Medical School, Newcastle upon Tyne
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Regnier GL, Guillonneau CG, Duhault JL, Tisserand FP, Saint-Romas G, Holstorp SM. New xanthine derivatives with potent and long lasting anti-bronchoconstrictive activity. Eur J Med Chem 1987. [DOI: 10.1016/0223-5234(87)90056-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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20
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Lee EH, Tsai MJ, Tang YP, Chai CY. Differential biochemical mechanisms mediate locomotor stimulation effects by caffeine and nicotine in rats. Pharmacol Biochem Behav 1987; 26:427-30. [PMID: 3033699 DOI: 10.1016/0091-3057(87)90142-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Effects of caffeine and the interactive effects of caffeine and nicotine on locomotor activity in rats were examined in the present study. Other than confirming previous reports that both drugs enhanced locomotion, we have also found that their effects on activity were additive. Meanwhile, results of various biochemical measures have revealed that at the minimum effective doses of caffeine and nicotine which facilitated locomotor activity, only one biochemical system was preferentially influenced by either drug alone. The most significant findings were that caffeine stimulated the release of catecholamines and nicotine decreased the concentrations of tyrosine and tryptophan in brain. The combined effects of caffeine and nicotine on these brain amines were not different from those of each drug alone. Together with the report that caffeine and nicotine had differential actions on different activity measures, the present results support the hypothesis that caffeine and nicotine affect locomotor activity via different neurochemical mechanisms.
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22
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Abstract
Adenosine has been implicated in neuromodulation in the central nervous system [(1985) Annu. Rev. Neurosci. 8, 103-124]. Its mechanism of action is thought to be a receptor-mediated inhibition of a transmitter release. To assess adenosine's role as a neuromodulator in the vestibular periphery, spontaneous activity of the afferent fibers in the ampullar nerve of the semicircular canal, in vitro, was used as the dependent variable. Afferent firing has been previously shown to depend on transmitter release by the hair cells [(1985) Brain Res. 330, 1-9]. Adenosine was shown to inhibit firing rate; the adenosine antagonist theophylline was shown to increase firing rate; the enzyme adenosine deaminase, which catabolizes adenosine to inosine, was shown to increase firing rate; the adenosine uptake inhibitor dipyridamole was shown to decrease firing rate; and adenosine was shown to be released from the isolated semicircular canal by electrical stimulation. All these findings are internally consistent and unreservedly support the hypothesis that adenosine has a neuromodulatory role in neurotransmission in the semicircular canal.
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Affiliation(s)
- G M Bryant
- Tulane University School of Medicine, Dept. of Pharmacology, New Orleans 70112
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23
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Persson CG, Gustafsson B. Tracheal relaxation from combinations of xanthines and of a beta 2-receptor agonist and xanthines. Lung 1986; 164:33-40. [PMID: 3081769 DOI: 10.1007/bf02713627] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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24
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Davies LP, Baird-Lambert J, Marwood JF. Studies on several pyrrolo[2,3-d]pyrimidine analogues of adenosine which lack significant agonist activity at A1 and A2 receptors but have potent pharmacological activity in vivo. Biochem Pharmacol 1986; 35:3021-9. [PMID: 3019353 DOI: 10.1016/0006-2952(86)90381-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
5'-Deoxy-5-iodotubercidin was previously reported to cause potent muscle relaxation and hypothermia when injected i.p. into mice. In normotensive rats, i.v. injection reduced blood pressure and heart rate. 5-Iodotubercidin possessed the same in vivo activities whereas tubercidin was pharmacologically almost inactive. None of these compounds interacted significantly with Al adenosine receptors, as determined by their ability to displace 3H-N6-phenylisopropyladenosine or 3H-5'-N-ethylcarboxamidoadenosine bound to rat brain membranes. Furthermore these compounds were much weaker than adenosine as agonists of adenosine-stimulated adenylate cyclase in guinea-pig brain slices (A2 receptors). A previous report showed that 5'-deoxy-5-iodotubercidin and 5-iodotubercidin were very potent inhibitors of adenosine kinase from rat or guinea-pig brain and were potent inhibitors of 3H-adenosine uptake into brain slices; relative to the halogenated derivatives, tubercidin was quite weak as an inhibitor of adenosine kinase and of adenosine uptake. We therefore propose that a significant part of the in vivo activity of the two halogenated tubercidin analogues may not be due to a direct agonist action at A1 and/or A2 adenosine sites (as proposed for a number of other metabolically-stable analogues of adenosine) but may result from an inhibition of reuptake of endogenously-released adenosine; the increased extracellular levels of adenosine resulting from this action could then interact directly with membrane receptors. Consistent with this, low concentrations of 5'-deoxy-5-iodotubercidin were shown to significantly potentiate the effects of exogenous adenosine on blood pressure and heart rate in anaesthetized rats and on adenosine-stimulated cAMP generation in guinea-pig brain slices. None of these compounds interacted with central benzodiazepine receptors. The cardiovascular and behavioural effects of 5'-deoxy-5-iodotubercidin and 5-iodotubercidin were blocked by theophylline; results from the cardiovascular studies suggest there may be different adenosine receptors in heart and blood vessels.
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Persson CG, Andersson KE, Kjellin G. Effects of enprofylline and theophylline may show the role of adenosine. Life Sci 1986; 38:1057-72. [PMID: 3007902 DOI: 10.1016/0024-3205(86)90241-9] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It is well established that at low and clinically relevant concentrations theophylline (and caffeine) exerts antagonism at cell surface receptor sites for adenosine. However, it is not known which actions of theophylline are due to adenosine antagonism, because theophylline apparently activates other cellular mechanisms at the same low concentrations. Investigations into the actions of xanthines and their structure activity relationships have identified xanthine compounds like enprofylline (3-propylxanthine) that only has some actions in common with theophylline and that has a negligible ability to antagonize adenosine. Enprofylline is a more potent smooth muscle relaxant and antiasthmatic drug than theophylline but does not produce, e.g., theophylline-like diuretic effects, CNS-stimulant behavioural effects (restlessness - seizures), gastric secretory effects and release of free fatty acids. It is proposed that pharmacodynamic dissimilarities between enprofylline and theophylline may indicate physiological roles of adenosine.
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26
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Mathew RJ, Wilson WH, Tant S. Caffeine-induced cerebral blood flow changes in schizophrenia. EUROPEAN ARCHIVES OF PSYCHIATRY AND NEUROLOGICAL SCIENCES 1986; 235:206-9. [PMID: 3699074 DOI: 10.1007/bf00379975] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Cerebral blood flow (CBF) measurements and mental status examinations were performed before and 30 min after oral administration of 250 mg of caffeine or a placebo given under double-blind conditions, in two groups of patients with schizophrenia. Caffeine produced significant CBF reductions but no changes in the patient's clinical condition.
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Abstract
While the caffeine induced cerebral vasoconstriction is well documented, the effects of oral ingestion of the drug in a dose range comparable to the quantities in which it is usually consumed and the intensity and duration of the associated reduction in cerebral circulation are unknown. Cerebral blood flow was measured via the 133Xenon inhalation technique before and thirty and ninety minutes after the oral administration of 250 mg of caffeine or a placebo, under double-blind conditions. Caffeine ingestion was found to be associated with significant reductions in cerebral perfusion thirty and ninety minutes later. The placebo group showed no differences between the three sets of cerebral blood flow values.
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28
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Aoki C. Development of the A1 adenosine receptors in the visual cortex of cats, dark-reared and normally reared. Brain Res 1985; 354:125-33. [PMID: 2994851 DOI: 10.1016/0165-3806(85)90075-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The ontogeny of the distribution of the binding sites for [3H]chlorohydroxyladenosine, an A1 adenosine receptor-specific ligand, was visualized autoradiographically within coronal sections of the visual cortical areas of developing cats. In adults, the A1 adenosine receptors were found in all lamina except for lamina IV, and in particularly high concentration within laminas I-III. In brains of kittens 2 months old and younger who were within the critical period for the development of visual neural function, the receptor distribution was less defined and sparser, except that in contrast to adults, it was found in relatively high concentration within lamina VI. Animals dark-reared from birth, so that the critical period was postponed, exhibited an ontogenetic pattern identical to that of the normally reared animals. These results indicate that, at least with respect to ocular dominance determination, A1 adenosine receptors are probably not involved in determining the state of plasticity that is seen during the critical period.
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29
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Stone TW, Lloyd HG. Effect of copper on the binding and electrophysiological actions of cyclohexyladenosine. Brain Res 1985; 336:187-9. [PMID: 4039961 DOI: 10.1016/0006-8993(85)90434-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Since copper ions irreversibly reduce the binding of cyclohexyladenosine (CHA) to rat brain membranes and copper levels are elevated in the brains of seizure-prone mice, the binding of CHA was compared in seizure-prone DBA/2 and control C57 mice. No strain difference was detected in the binding of CHA or the reduction of that binding by copper, although copper was more potent than in rats (IC50 12 microM). In rat hippocampal slices copper did not diminish the inhibitory effects of adenosine or CHA. The results suggest that the seizure sensitivity of DBA/2 mice is not due to an effect of copper on purine receptors and that the copper binding domain of purine receptors is inaccessible to extracellular copper.
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30
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Holloway FA, Modrow HE, Michaelis RC. Methylxanthine discrimination in the rat: possible benzodiazepine and adenosine mechanisms. Pharmacol Biochem Behav 1985; 22:815-24. [PMID: 2989946 DOI: 10.1016/0091-3057(85)90533-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rats were trained to discriminate either caffeine or theophylline from saline using a two-lever discrimination paradigm. Since methylxanthines have been found to interfere with agonist binding at both adenosine and benzodiazepine (BDZ) receptors, chlordiazepoxide (CDP) and L-PIA (an adenosine analog) were tested for generalization to and blockade of both xanthine cues. Neither L-PIA nor CDP generalized to either xanthine cue, although both produced dose-related decreases in response rate. CDP, but not L-PIA, produced dose-related decreases in drug-lever responses when combined with training doses of caffeine or theophylline. Response rates indicated a complex interaction between the xanthines and both L-PIA and CDP. When combined with the caffeine training dose, pentobarbital also produced a dose-dependent decrease in response rate but not in drug lever choices. Finally, papaverine generalized to the caffeine cue in a dose-dependent fashion. In a second experiment, rats trained to discriminate CDP from saline showed no generalization in L-PIA tests. CDP-appropriate responding was not significantly affected when the CDP training dose was combined with caffeine. These data indicate that: (a) methylxanthine interactions with L-PIA and CDP on response rate likely involve blockade of adenosine mechanisms; (b) the xanthine cue does not appear to depend on interactions with adenosine receptors; and (c) the xanthine cue may involve effects on cyclic AMP activity and/or interaction with the BDZ/GABA receptor complex.
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31
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Adenosine-induced depression of synaptic transmission in the isolated olfactory cortex: receptor identification. Pflugers Arch 1985; 403:141-5. [PMID: 2984640 DOI: 10.1007/bf00584091] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have investigated the type of purine receptor in the guinea-pig olfactory cortex, using pial surfaces slices maintained in vitro. Adenosine (0.1 to 100 mumol/l) bath applied in the presence of the uptake inhibitor nitrobenzylthioinosine, depressed the evoked potentials in a dose related fashion. Synthetic and uptake resistant adenosine analogues had the same effect as adenosine and the order of potency of these was: 5'-N-ethylcarboxamide adenosine greater than L-N6-phenylisopropyl adenosine (L-PIA) = N6-cyclohexyladenosine = 2-chloroadenosine greater than adenosine greater than D-N6-phenylisopropyladenosine (D-PIA). The D-stereoisomer of PIA was 45 times less potent than L-PIA. The methylxanthine compounds 8-phenyltheophylline (3 mumol/l) and 3-isobutyl-1-methylxanthine (50 mumol/l) antagonised the depression produced by L-PIA. Rolipram, a phosphodiesterase inhibitor, in concentrations up to 100 mumol/l had no effect on the evoked potentials or on adenosine action. Forskolin, a cAMP stimulant, slightly increased the amplitude of the evoked potential, and partly reversed the depressant effect of adenosine. Noradrenaline had no effect either alone or in the presence of adenosine. The results of these experiments indicate the existence of A1 subtype adenosine receptors in the guinea pig olfactory cortex probably linked to a depression of intracellular cAMP.
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32
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Van Renterghem C, Renit-Soria J, Stinnakre J. beta-Adrenergic induced K+ current in Xenopus oocytes: role of cAMP, inhibition by muscarinic agents. PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. SERIES B, BIOLOGICAL SCIENCES 1985; 223:389-402. [PMID: 2579401 DOI: 10.1098/rspb.1985.0008] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The K+ current induced by isoprenaline acting on beta-adrenergic receptors in Xenopus laevis has been studied in oocytes still surrounded by their follicular cells and inner ovarian epithelium. Forskolin, an adenylate cyclase activator, induced a similar K+ current and when used at subliminal concentration it potentiated the current induced by isoprenaline. Inhibition of phosphodiesterase by methylisobutylxanthine also enhanced the response to isoprenaline. 8-Br-cAMP, a permeant analogue of cAMP also produced a K+ current. Acetylcholine produced a long lasting inhibition of the isoprenaline current. This inhibition was not seen in the presence of atropine. It is concluded that the K+ current induced by the activation of beta-adrenergic receptors in the oocyte is mediated by an intracellular rise of cAMP.
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33
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Dunwiddie TV. The physiological role of adenosine in the central nervous system. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1985; 27:63-139. [PMID: 2867982 DOI: 10.1016/s0074-7742(08)60556-5] [Citation(s) in RCA: 514] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
Male Sprague Dawley rats were tested for open field ambulation and rearing, and for wheelrunning, following repeated injections of either caffeine or nicotine, given according to a Latin Square design. Caffeine enhanced ambulation and rearing at 5 and 15 mg/kg, IP, and increased wheelrunning with 15 and 45 mg/kg. Nicotine (0.63 mg/kg) also enhanced ambulation, but not rearing, and depressed wheelrunning during the first 20 min of testing. Caffeine's enhancement of wheelrunning was not significant during the first two drug administrations. Results suggest that caffeine and nicotine affect activity via different neuropharmacological mechanisms. Previous experience with these drugs may modulate animals' reactivity to them.
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35
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Davies LP, Chow SC, Skerritt JH, Brown DJ, Johnston GA. Pyrazolo[3,4-d]pyrimidines as adenosine antagonists. Life Sci 1984; 34:2117-28. [PMID: 6328156 DOI: 10.1016/0024-3205(84)90310-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A large number of nitrogen heterocycles structurally related to caffeine and theophylline have been tested for activity as adenosine antagonists. Preliminary screening, utilizing displacement of [3H]N6-phenylisopropyladenosine (PIA) binding to rat brain membranes, identified several pyrazolo[3,4-d]pyrimidines with potential antagonist activity. These were then tested for their ability to antagonize adenosine-stimulated adenylate cyclase of guinea-pig slices and to block adenosine receptors which mediate presynaptic inhibition of transmitter release from cholinergic nerves in guinea-pig ileum. Of several compounds found to have antagonist activity, one of these, 4,6-bis-alpha- carbamoylethylthio -1-phenylpyrazolo[3,4-d]pyrimidine ( DJB -KK) was approximately an order of magnitude more potent than theophylline in both tests. GTP greatly reduces the potency of purine agonists, but not antagonists, as inhibitors of [3H] PIA binding; the potency of the pyrazolo[3,4-d]pyrimidine compounds was not altered by GTP. The compounds have no significant activity against [3H]adenosine uptake or on the binding of ligands to muscarinic cholinergic, beta-adrenergic, GABA or L-glutamate receptors.
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36
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Nehlig A, Lucignani G, Kadekaro M, Porrino LJ, Sokoloff L. Effects of acute administration of caffeine on local cerebral glucose utilization in the rat. Eur J Pharmacol 1984; 101:91-100. [PMID: 6086367 DOI: 10.1016/0014-2999(84)90034-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The quantitative 2-[14C]deoxyglucose autoradiographic method was used to study the effects of acute intravenous injections (15 min prior to study) of caffeine on brain energy metabolism. With doses of 0.1 mg/kg the effects of caffeine on cerebral glucose utilization were limited to the habenula, spinal trigeminal and paraventricular nuclei. After the 1.0 mg/kg dose significant increases were additionally seen in the caudate, ventral tegmental area and medial septum. After the injection of 10 mg/kg of caffeine, average glucose utilization of the brain as a whole was increased by 15%, and of 71 structures examined 31 structures were statistically significantly affected. Among these were all brainstem monoaminergic cell groupings, components of the extrapyramidal motor system, anterior cingulate, and medial prefrontal cortex. In the hypothalamus glucose utilization increased only in the paraventricular nucleus, arcuate nucleus, and median eminence. This study demonstrates that there is a correlation between the known stimulant effects of caffeine on behavior and widespread increases in glucose utilization throughout the brain.
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37
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Nagy JI, LaBella LA, Buss M, Daddona PE. Immunohistochemistry of adenosine deaminase: implications for adenosine neurotransmission. Science 1984; 224:166-8. [PMID: 6142530 DOI: 10.1126/science.6142530] [Citation(s) in RCA: 133] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Immunohistochemical analysis of adenosine deaminase in rat brain revealed an extensive plexus of adenosine deaminase-containing neurons in the basal hypothalamus. These neurons converged on and were most numerous in three major centers, namely, the tuberal, caudal, and postmammillary caudal magnocellular nuclei. Most other brain regions were devoid of cells containing adenosine deaminase. Some adenosine deaminase-containing neurons were retrogradely labeled with the fluorescent dye fast blue when the dye was injected into the frontal cortex and striatum. Specific populations of neurons having high levels of adenosine deaminase may release adenosine as a neurotransmitter.
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38
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39
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Carley WW, Lipsky MG, Webb WW. Regulation and drug insensitivity of F-actin association with adhesion areas of transformed cells. J Cell Physiol 1983; 117:257-65. [PMID: 6313706 DOI: 10.1002/jcp.1041170218] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
F-actin aggregates have been found near the substrate attachments in a variety of transformed cells (Carley et al., 1981). Interference reflection microscopy shows that these aggregates are present in central close adhesion areas in Rous sarcoma virus (RSV)-transformed rat kidney cells. If these transformed cells are incubated with N6, O2-dibutyryl 3':5'-cyclic monophosphoric acid (db-cAMP), adenosine 5'-monophosphoric acid (5'-AMP) or adenosine, the F-actin aggregates and their associated close adhesion areas disappear, and the cells flatten out. Treatment of untransformed cells with db-cAMP spreads their focal adhesion plaques and thickens microfilament bundles. Furthermore, F-actin aggregates are substantially more resistant to cytochalasin B and the Ca2+ ionophore A23187 than microfilament bundles in untransformed cells. These differences between F-actin complexes in untransformed and in RSV-transformed cells, with respect to morphology and sensitivities to db-cAMP and cytoskeleton-disrupting drugs, define properties of the change in F-actin regulation and association with the plasma membrane due to transformation.
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40
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Davies LP, Brown DJ, Chow SC, Johnston GA. Pyrazolo [3,4-d] pyrimidines, a new class of adenosine antagonists. Neurosci Lett 1983; 41:189-93. [PMID: 6316216 DOI: 10.1016/0304-3940(83)90245-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A variety of nitrogen heterocycles structurally related to caffeine and theophylline have been tested for activity as adenosine receptor antagonists. Preliminary screening, utilizing displacement of [3H]N6-phenylisopropyladenosine binding to rat brain membrane A1-adenosine receptors, identified several pyrazolo[3,4-d]pyrimidines with potential antagonist activity. These were then tested for their ability to antagonize the adenosine-stimulated adenylate cyclase system of guinea-pig brain slices. One of these, 4,6-bis-alpha-carbamoylethylthio-1-phenylpyrazolo[3,4-d]pyrimidine (DJB-KK), was over an order of magnitude more potent than theophylline in blocking adenosine-stimulated increases in cyclic AMP levels.
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41
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Eldridge FL, Millhorn DE, Waldrop TG, Kiley JP. Mechanism of respiratory effects of methylxanthines. RESPIRATION PHYSIOLOGY 1983; 53:239-61. [PMID: 6579584 DOI: 10.1016/0034-5687(83)90070-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Neural respiratory responses to theophylline, aminophylline and ethylenediamine were determined in paralyzed, vagotomized and glomectomized cats whose end-tidal PCO2 and brain temperature were kept constant. Intravenous theophylline and aminophylline similarly stimulated respiration, but ethylenediamine had no effect. The following did not cause the response: muscular and mechanical factors, carotid body and vagal reflexes, spinally mediated mechanisms arising below C7, changes of arterial PCO2 or medullary ECF pH, changes of whole body metabolic rate or release of substances from the adrenal glands. Absence of suprapontine brain did not prevent the response. Pretreatment with a serotonin antagonist did not affect the response but two different dopamine antagonists caused its attenuation. When administered into the third ventricle, theophylline did not stimulate respiration, but both aminophylline and ethylenediamine, due to the latter's ability to mimic the inhibitory effects on neurons of gamma-aminobutyric acid (GABA), caused significant depression of respiration. We conclude that the neural respiratory response to systemically administered theophylline is mediated at the level of the brainstem, and somehow involves the action of the neurochemical dopamine. The failure of cerebroventricularly administered theophylline to stimulate respiration must be related to its inability to reach the appropriate neurons from the cerebrospinal fluid.
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42
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Nakata H, Fujisawa H. Solubilization and partial characterization of adenosine binding sites from rat brainstem. FEBS Lett 1983; 158:93-7. [PMID: 6305727 DOI: 10.1016/0014-5793(83)80683-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Binding sites for adenosine were solubilized from rat brainstem membranes with either sodium cholate, sodium deoxycholate or 3-[(3-cholamidopropyl)dimethyl-ammonio]-1-propanesulfonate. About 30% of the binding activity were released by [3H]phenylisopropyladenosine (PIA) binding. Specific [3H]PIA binding to the solubilized fraction was saturable and was found to be a monophasic saturation profile. In contrast, [3H]PIA binding to the brainstem membranes exhibited a biphasic profile suggesting the presence of two binding sites. By gel filtration on a Sepharose CL-6B column, the adenosine binding site--detergent complex was estimated to have app. Mr 280000 and rs = 5.4 nm.
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43
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Agren H, Niklasson F, Hällgren R. Brain purinergic activity linked with depressive symptomatology: hypoxanthine and xanthine in CSF of patients with major depressive disorders. Psychiatry Res 1983; 9:179-89. [PMID: 6578531 DOI: 10.1016/0165-1781(83)90042-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The purine metabolites hypoxanthine and xanthine were analyzed in cerebrospinal fluid (CSF) of 70 patients with major depressive disorders (diagnosed according to Research Diagnostic Criteria) and, for reference, in 26 nonpsychiatric individuals. In the patient group, levels adjusted by analysis of covariance to same sex, age, height, and weight were univariately and multivariately correlated with both depressive subdiagnoses and individual depressive symptoms. Results indicate that raw CSF levels in depressed patients are significantly correlated with the four variables used in adjustment (for hypoxanthine mainly negatively with height; for xanthine mainly positively with age). Hypoxanthine and xanthine both appear to be linked with the expression of depressive symptomatology: lower levels of hypoxanthine are associated with anger and suicidal tendencies, and higher levels are related to memory disturbance; lower xanthine levels characterize patients with subjective feelings of depression, and in patients with higher levels appetite is poor.
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44
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Crawley JN, Patel J, Marangos PJ. Adenosine uptake inhibitors potentiate the sedative effects of adenosine. Neurosci Lett 1983; 36:169-74. [PMID: 6306520 DOI: 10.1016/0304-3940(83)90260-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A major action of adenosine is the induction of profound behavioral inactivity. 6-(4-Nitrobenzyl)-thioinosine (NBI) and 6-(2-hydroxy-5-nitrobenzyl)-thioguanosine (NBG) have been shown to inhibit adenosine uptake. To investigate the possible synergism between exogenous ligand and reuptake inhibition, mice were treated with NBI or NBG + adenosine. NBI and NBG potentiated the effects of adenosine at doses which did not in themselves induce behavioral inactivity. These behavioral results support the proposed role of NBI and NBG as adenosine uptake site blockers which increase synaptic concentrations of adenosine and postsynaptic responses to adenosine in vivo.
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45
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Nistri A, Berti C. Caffeine-induced potentiation of GABA effects on frog spinal cord: an electrophysiological study. Brain Res 1983; 258:263-70. [PMID: 6600642 DOI: 10.1016/0006-8993(83)91149-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A parasagittal slice of the frog spinal cord was kept in vitro for electrophysiological recordings from dorsal and ventral roots. Low concentrations of caffeine (50 microM) which had relatively small effects on baseline electrical activity, increased the depolarizing action of GABA on dorsal root fibres by 50%. A similar result was also obtained when GABA motoneuronal responses were tested. On dorsal roots the potentiation of GABA responses by caffeine was reflected by a significant decrease in GABA ED50 value without change in the maximal response amplitude; this enhancing action of caffeine was not blocked by bicuculline (5 microM) but was abolished by flurazepam (5 microM) or by Ca2+ antagonists (Mn2+ and Cd2+). Blockade of interneuronal activity by procaine left the potentiating action of caffeine unchanged. High doses of caffeine (up to 1 mM) produced a seemingly non-competitive antagonism of GABA responses. We suggest that caffeine can modulate GABA responses through two different mechanisms: a potentiation of GABA effects (seen with low doses of caffeine) probably due to Ca2+ mobilization and an antagonism of GABA responses (typically seen with large doses of caffeine) perhaps caused by block of GABA receptor-activated channels. This novel caffeine-GABA interaction may be useful to interpret some of the effects of caffeine on mammalian behaviour.
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46
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Galloway MP, Roth RH. Clonidine prevents methylxanthine stimulation of norepinephrine metabolism in rat brain. J Neurochem 1983; 40:246-51. [PMID: 6184449 DOI: 10.1111/j.1471-4159.1983.tb12678.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Methylxanthines can produce behavior resembling opiate withdrawal in rats. Since previous studies have demonstrated the involvement of central noradrenergic systems during naloxone-precipitated withdrawal, the effects of 3-isobutyl-1-methylxanthine (IBMX) on norepinephrine metabolism in rat brain were studied. It was found that administration of IBMX elevated levels of the major norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) in areas innervated by the locus coeruleus. The increases in MHPG was noted 1 h after administration and was maximal (270% of control) after 3 h. Levels of another norepinephrine metabolite, 3,4-dihydroxyphenylglycol, followed a similar pattern and time course. Coadministration of naloxone with IBMX did not affect the IBMX-induced elevation in MHPG. Administration of the alpha-agonist clonidine, however, antagonized the effects of IBMX on MHPG levels. The effects of IBMX and clonidine were dose dependent; the lowest dose of IBMX needed to elevate MHPG was 30 mumol/kg (i.p.), and clonidine (180 nmol/kg) reduced the effect of IBMX (100 mumol/kg) by 50%. The data, discussed in terms of a methylxanthine-noradrenergic interaction, suggest that withdrawal behaviors in general may be subserved by hyperactive noradrenergic neurons.
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47
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Viveros OH, Wilson SP. The adrenal chromaffin cell as a model to study the co-secretion of enkephalins and catecholamines. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1983; 7:41-58. [PMID: 6302158 DOI: 10.1016/0165-1838(83)90068-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The enkephalins, endogenous opioid pentapeptides first discovered in brain, are present in high concentrations in the adrenal medulla chromaffin cell. The enkephalins and other peptides containing enkephalin sequences are stored with catecholamines in the secretory organelles (chromaffin vesicles); these peptides are apparently incorporated into the vesicles at the time of their biosynthesis as opposed to later accumulation, as is the case with catecholamines. The enkephalins, catecholamines and other soluble components of the vesicle are co-secreted by the process of exocytosis. Regulatory mechanisms, apparently triggered by a critical catecholamine pool, control the synthesis of enkephalins. These mechanisms allow for rapid recovery of enkephalin content after secretion. These findings have been extended from the chromaffin cell to the ontogenically related sympathetic neurons and pheochromocytoma tumors. Secreted enkephalins and related peptides reach ubiquitous opiate receptors through the synaptic gap or the circulation and may modulate a number of important systemic functions. The co-storage and co-secretion of adrenomedullary opioid peptides and catecholamines is only one of a growing number of examples of co-existence of multiple messengers in single neuronal or endocrine cell types. Co-secreted multiple messengers may act in a co-ordinated fashion to produce integrated organismal responses.
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Lal H, Gherezghiher T, Carney J. Ineffectiveness of a purine analogue, EMD 28422, in two animal tests of anxiolytic action. Drug Dev Res 1983. [DOI: 10.1002/ddr.430030109] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wu PH, Phillis JW, Nye MJ. Alkylxanthines as adenosine receptor antagonists and membrane phosphodiesterase inhibitors in central nervous tissue: evaluation of structure-activity relationships. Life Sci 1982; 31:2857-67. [PMID: 6298531 DOI: 10.1016/0024-3205(82)90676-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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