@article{LohseKlotzSchwabe1991,
  author    = {Lohse, Martin J. and Klotz, Karl-Norbert and Schwabe, Ulrich},
  title     = {Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86073},
  year      = {1991},
  abstract  = {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. 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)].},
  subject      = {Adenosinrezeptor},
  language  = {en}
}
@incollection{LohseKlotzSchwabe1985,
  author    = {Lohse, Martin J. and Klotz, Karl-Norbert and Schwabe, Ulrich},
  title     = {Effects of barbiturates on A1 adenosine receptors of rat brain},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70100},
  publisher      = {Universit{\"a}t W{\"u}rzburg},
  year      = {1985},
  abstract  = {Barbiturates inhibit binding of radioligands to A 1(Ri) adenosine receptors of rat brain membranes. This inhibition is dose-dependent and stereospecific and occurs in the range of pharmacologically active concentrations. The displacement of radiolabelled A1antagonists by barbiturates is not modified by GTP, indicating that barbiturates might act as antagonists at this receptor. This action of barbiturates does not seem to be related to the binding of barbiturates to plasma membranes, as the latter process has different characteristics. Barbiturates also inhibit the binding of radioligands to solubilized A1receptors, and saturation and kinetic experiments suggest that this is due to a competitive antagonism. These results indicate that barbiturates interact with the recognition site of the A1adenosine receptor.},
  subject      = {Barbiturat},
  language  = {en}
}
@incollection{LohseKlotzSchwabe1987,
  author    = {Lohse, Martin J. and Klotz, Karl-Norbert and Schwabe, Ulrich},
  title     = {Functional characterization of A1 adenoosine receptors by photoaffinity labelling},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86097},
  publisher      = {Universit{\"a}t W{\"u}rzburg},
  year      = {1987},
  abstract  = {The ligand-binding subunit ofthe A1 adenosine receptor has been identified in membranes with the photoaffinity Iabel R-2-azido-N6-p-hydroxyphenylisopropyladenosine (R-AHPIA). Covalent labelling ofthe A1 receptor can also be achieved in intact cells. The dissociation of the radioiodinated label (1251-AHPIA) from isolated rat fat cells was incomplete after UV irradiation, leaving about 20°/o of irreversible specific binding. Such covalent labelling of the receptor led to a concentration-dependent reduction of cellular cyclic AMP levels. This persistent effect of covalent labeHing occurred with an IC50 value of 9 nM, as compared to an IC50 value of 0.9 nM for the direct reduction of cyclic AMP Ievels by the ligand. The difference in the IC5o values can be explained by assuming spare receptors. This hypothesis was verified in binding studies using [ 3HJPIA as a radioligand. R-AHPIA inhibited binding of [3H)PIA to intact fat cells with a K1 value of about 20 nM, which is about 20 tim es high er than the corresponding IC50 value of cyclic AMP reduction. These data show that the A1 receptor is activated according to the occupancy theory. The high sensitivity of the activation in intact ceJis is due to a large number of spare receptors.},
  subject      = {Adenosinrezeptor},
  language  = {en}
}