%0 Journal Article %1 Klotz1989 %A Klotz, K. N. %A Lohse, M. J. %A Schwabe, U. %A Cristalli, G. %A Vittori, S. %A Grifantini, M. %D 1989 %J Naunyn Schmiedebergs Arch Pharmacol %K & Adenosine/*analogs Animals Brain/metabolism Catalysis Isotope Kinetics Labeling Magnetic Oxidation-Reduction Purinergic/*drug Rats Resonance Spectroscopy derivatives/pharmacology effects Receptor %N 6 %P 679-83 %T 2-Chloro-N6-3Hcyclopentyladenosine (3HCCPA)--a high affinity agonist radioligand for A1 adenosine receptors %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=2615857 %V 340 %X The tritiated analogue of 2-chloro-N6-cyclopentyladenosine (CCPA), an adenosine derivative with subnanomolar affinity and a 10,000-fold selectivity for A1 adenosine receptors, has been examined as a new agonist radioligand. 3HCCPA was prepared with a specific radioactivity of 1.58 TBq/mmol (43 Ci/mmol) and bound in a reversible manner to A1 receptors from rat brain membranes with a high affinity KD-value of 0.2 nmol/l. In the presence of GTP a KD-value of 13 nmol/l was determined for the low affinity state for agonist binding. Competition of several adenosine receptor agonists and antagonists for 3HCCPA binding to rat brain membranes confirmed binding to an A1 receptor. Solubilized A1 receptors bound 3HCCPA with similar affinity for the high affinity state. At solubilized receptors a reduced association rate was observed in the presence of MgCl2, as has been shown for the agonist 3HN6-phenylisopropyladenosine (3HPIA). 3HCCPA was also used for detection of A1 receptors in rat cardio myocyte membranes, a tissue with a very low receptor density. A KD-value of 0.4 nmol/l and a Bmax-value of 16 fmol/mg protein was determined in these membranes. In human platelet membranes no specific binding of 3HCCPA was measured at concentrations up to 400 nmol/l, indicating that A2 receptors did not bind 3HCCPA. Based on the subnanomolar affinity and the high selectivity for A1 receptors 3HCCPA proved to be a useful agonist radioligand for characterization of A1 adenosine receptors also in tissues with very low receptor density.

@article{Klotz1989, abstract = {The tritiated analogue of 2-chloro-N6-cyclopentyladenosine (CCPA), an adenosine derivative with subnanomolar affinity and a 10,000-fold selectivity for A1 adenosine receptors, has been examined as a new agonist radioligand. [3H]CCPA was prepared with a specific radioactivity of 1.58 TBq/mmol (43 Ci/mmol) and bound in a reversible manner to A1 receptors from rat brain membranes with a high affinity KD-value of 0.2 nmol/l. In the presence of GTP a KD-value of 13 nmol/l was determined for the low affinity state for agonist binding. Competition of several adenosine receptor agonists and antagonists for [3H]CCPA binding to rat brain membranes confirmed binding to an A1 receptor. Solubilized A1 receptors bound [3H]CCPA with similar affinity for the high affinity state. At solubilized receptors a reduced association rate was observed in the presence of MgCl2, as has been shown for the agonist [3H]N6-phenylisopropyladenosine ([3H]PIA). [3H]CCPA was also used for detection of A1 receptors in rat cardio myocyte membranes, a tissue with a very low receptor density. A KD-value of 0.4 nmol/l and a Bmax-value of 16 fmol/mg protein was determined in these membranes. In human platelet membranes no specific binding of [3H]CCPA was measured at concentrations up to 400 nmol/l, indicating that A2 receptors did not bind [3H]CCPA. Based on the subnanomolar affinity and the high selectivity for A1 receptors [3H]CCPA proved to be a useful agonist radioligand for characterization of A1 adenosine receptors also in tissues with very low receptor density.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Klotz, K. N. and Lohse, M. J. and Schwabe, U. and Cristalli, G. and Vittori, S. and Grifantini, M.}, biburl = {https://www.bibsonomy.org/bibtex/2c8e27d897591ee4450f297b38d586a89/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {788a2b94ef5e6b2cb34c734d0109e47e}, intrahash = {c8e27d897591ee4450f297b38d586a89}, issn = {0028-1298 (Print) 0028-1298 (Linking)}, journal = {Naunyn Schmiedebergs Arch Pharmacol}, keywords = {& Adenosine/*analogs Animals Brain/metabolism Catalysis Isotope Kinetics Labeling Magnetic Oxidation-Reduction Purinergic/*drug Rats Resonance Spectroscopy derivatives/pharmacology effects Receptor}, month = Dec, note = {Klotz, K N Lohse, M J Schwabe, U Cristalli, G Vittori, S Grifantini, M In Vitro Research Support, Non-U.S. Gov't Germany, west Naunyn-Schmiedeberg's archives of pharmacology Naunyn Schmiedebergs Arch Pharmacol. 1989 Dec;340(6):679-83.}, number = 6, pages = {679-83}, shorttitle = {2-Chloro-N6-[3H]cyclopentyladenosine ([3H]CCPA)--a high affinity agonist radioligand for A1 adenosine receptors}, timestamp = {2010-12-14T18:20:05.000+0100}, title = {2-Chloro-N6-[3H]cyclopentyladenosine ([3H]CCPA)--a high affinity agonist radioligand for A1 adenosine receptors}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=2615857}, volume = 340, year = 1989 }