...Aqsa Malik; Leslie Thomas Buck SUMMARY Adenosine has been termed a retaliatory metabolite and its neuroprotective effects have been implicated in the hypoxia tolerance of several species; however, its role in the invertebrate CNS remains unclear. To determine if adenosine modulates neuronal...

...L. G. Eckerle; M. Lucassen; T. Hirse; H. O. Pörtner SUMMARY Exposure of ectothermic organisms to variations in temperatures causes a transient mismatch between energy supply and demand, which needs to be compensated for during acclimation. Adenosine accumulation from ATP breakdown indicates...

... at high concentrations. The effects of 5-HT were blocked by methysergide. In the prometamorphic tadpole, ATP elicited relaxation that was blocked by the ectonucleotidase inhibitor ARL67156 and the adenosine A 1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), suggesting adenosine...

...Gereon Maurer; Jerrel L. Wilkens; Manfred K. Grieshaber SUMMARY As shown previously, adenosine and the adenine nucleotides cause a rapid increase in heart rate ( f H ) and haemolymph velocity( v HL ) when infused into intact American lobster( Homarus americanus ). Here we compare the effects...

...T. J. MacCormack; W. R. Driedzic SUMMARY Adenosine is a product of adenylate phosphate breakdown that can exert protective effects on tissues during energy limitation. Accumulation of cardiac adenosine under hypoxia is well documented in mammals but has not been shown in fish. Adenosine content...

... connected to a SMART system. Analysis of the purified active fraction by mass spectrometry demonstrated the presence of adenosine as the single organic compound in the extract that had a stimulatory effect on Na + transport. In a separate series of experiments, we confirmed that 1 μmol l -1 adenosine had...

... of tissues we tested ATP and adenosine for their effects on epithelial transport. Examination of integuments from pondwater- and high-salinity-adapted leeches revealed different sensitivities for these purines. Apical and basolateral application of ATP both stimulated transepithelial Na + uptake and I ami...

... in extracellular [K + ] during the initial phase of anoxic depolarization. However, unlike the anoxia-tolerant turtle brain, adenosine did not appear to be involved in the downregulation of K + leakage in the frog brain. The increased anoxia-tolerance of the frog brain is thought to be a matter more of slow death...

...Eva Stegen; Manfred K. Grieshaber ABSTRACT The effects of adenosine and adenine nucleotides on haemolymph velocity and on heart rate and scaphognathite frequency were investigated in the American lobster Homarus americanus . The infusion of 0.25–2.4 nmol g −1 min −1 adenosine produced steady-state...

...José M. C. Ribeiro; Oren Katz; Lewis K. Pannell; John Waitumbi; Alon Warburg ABSTRACT Salivary gland homogenates of the sand fly Phlebotomus papatasi contain large amounts of adenosine and 5′-AMP, of the order of 1 nmol per pair of glands, as demonstrated by liquid chromatography, ultraviolet...

...Thorsten Schwerte; Susanne Holmgren; Bernd Pelster ABSTRACT The effects of β-adrenergic stimulation, vasoactive intestinal polypeptide (VIP), adenosine, the nitric oxide (NO)-releasing agent sodium nitroprusside and of metabolic end-products of gas gland cell metabolism on swimbladder blood flow...

... studied: there is no adenosine-mediated increase in cerebral blood flow such as that occurring in freshwater turtles and cyprinid fish. However, blood pressure showed a 50 % decrease in the epaulette shark during hypoxia, indicating that a compensatory cerebral vasodilatation occurs to maintain cerebral...

...Tariq Mustafa; Claudio Agnisola ABSTRACT A vasoconstrictory response to adenosine has been reported in coronary rings from fish. Since the reactivity of the large coronary arteries and the microcirculation may differ, the present study was undertaken to determine the role of adenosine in the intact...

... largely by the N -methyl-D-aspartate (NMDA) subfamily of glutamate receptors. Adenosine has been shown to decrease the magnitude of the hypoxia-induced increase in [Ca 2+ ] i in mammalian brain slices, delaying tissue injury. Turtle brain is remarkably tolerant of anoxia, maintaining a pre-anoxic [Ca 2...

... to anoxia at 25 °C, there is an immediate fall in brain ATP levels, which reach approximately 20 % of normoxic levels in approximately 60 min. The frog, nevertheless, survives another 1–2 h of anoxia. At 100 min of anoxia, there is an increase in extracellular adenosine concentration, probably originating...

..., and (3) the potential modulatory effects of NECA, an adenosine receptor agonist, and DPSPX, an adenosine receptor antagonist, on catecholamine release. Bolus injections of ACTH, serotonin or carbachol, or perfusion with high-[K + ] saline, all elicited the release of both adrenaline and noradrenaline...

...Nicholas J. Bernier; Joelle Harris; Joanne Lessard; David J. Randall ABSTRACT The physiological properties of adenosine may be essential in the control of energy metabolism for the survival of animals exposed to oxygen shortages. Accordingly, we tested the hypothesis that adenosine modulates...

...Nicholas J. Bernier; Juan Fuentes; David J. Randall ABSTRACT The purpose of this study was to examine the role of adenosine receptors (ARs) in (1) the regulation of catecholamine secretion and (2) the modulation of blood oxygen capacitance by catecholamines. To this end, we assessed the response...

...Martha Kaloyianni; Basile Michaelidis; Katerina Moutou ABSTRACT The effects of adenosine and inosine on Rana ridibunda erythrocyte metabolism were studied. Adenosine can be metabolized by Rana ridibunda erythrocytes as a carbon source for glycolysis to maintain ATP levels, whereas neither inosine...

... obscure. * Permanent address: Department of Zoophysiology, Box 560, S-75122 Uppsala, Sweden. 21 8 1991 © 1992 by Company of Biologists 1992 adenosine anoxia ATP energetics hypoxia metabolic depression turtle Pseudemys scripta Neurotransmitters are ubiquitous...