• search hit 1 of 13
Back to Result List

Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling

Please always quote using this URN: urn:nbn:de:bvb:20-opus-86073
  • It has previously been shown that covalent incorporation of the photoreactive adenosine derivative (R)-2-azido-N6-p-hydroxyphenytisopropyladenosine [(R)-AHPIA] into the A, adenosine receptor of intact fat cells leads to a persistent activation of this receptor, resulting in a reduction of celular cAMP Ieveis [Mol. Pharmacol. 30:403-409 (1986)]. In contrast, covalent incorporation of (R)-AHPIA into human platelet membranes, which contain only stimulatory A2 adenosine receptors, reduces adenytate cyclase Stimulation via these receptors. ThisIt has previously been shown that covalent incorporation of the photoreactive adenosine derivative (R)-2-azido-N6-p-hydroxyphenytisopropyladenosine [(R)-AHPIA] into the A, adenosine receptor of intact fat cells leads to a persistent activation of this receptor, resulting in a reduction of celular cAMP Ieveis [Mol. Pharmacol. 30:403-409 (1986)]. In contrast, covalent incorporation of (R)-AHPIA into human platelet membranes, which contain only stimulatory A2 adenosine receptors, reduces adenytate cyclase Stimulation via these receptors. This effect of (R)-AHPIA is specific for the A2 receptor and can be prevented by the adenosine receptor antagonist theophylline. Binding studies in-dicate that up to 90% of A2 receptors can be blocked by photoincorporation of (R)-AHPIA. However, the remaining 10-20% of A2 receptors are sufficient to mediate an adenylate cyclase Stimulation of up to SOOk of the control value. Similarly, the activation via these 10-20% of receptors occurs with a halflife that is only 2 times Ionger than that in control membranes. This indicates the presence of a receptor reserve, with respect to both the extent and the rate of adenytate cyclase Stimulation. These observations require a modification of the models of receptor-adenytate cyclase coupling, which is described in the accompanying paper [Mol. Pharmacol. 39:524-530 (1991)].show moreshow less

Download full text files

Export metadata

Additional Services

Share in Twitter Search Google Scholar Statistics
Metadaten
Author: Martin J. Lohse, Karl-Norbert Klotz, Ulrich Schwabe
URN:urn:nbn:de:bvb:20-opus-86073
Document Type:Journal article
Faculties:Medizinische Fakultät / Institut für Pharmakologie und Toxikologie
Language:English
Year of Completion:1991
Source:In: Molecular Pharmacology, 1991, 39, S.517-523
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
GND Keyword:Adenosinrezeptor
Release Date:2014/06/03
Licence (German):License LogoDeutsches Urheberrecht