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$[^{3}$H]Dipyridamole Binding to Guinea Pig Brain Membranes: Possible Heterogeneity of Central Adenosine Uptake Sites
| Content Provider | Scilit |
|---|---|
| Author | Marangos, Paul J. Deckert, Jurgen |
| Copyright Year | 1987 |
| Description | Journal: Journal of Neurochemistry The binding of $[^{3}$H]dipyridamole $([^{3}$H]DPR) to guinea pig brain membranes is described and compared to that of $[^{3}$H]nitrobenzylthioinosine $([^{3}$H]NBI). The binding of $[^{3}$H]DPR is saturable, reversible, and specific with phar-macologic evidence indicating that this ligand is binding to the adenosine uptake site. Compared to $[^{3}$H]NBI the binding of $[^{3}$H]DPR is of higher capacity $(B_{max}$= 208 ±16 fmol/ mg protein for $[^{3}$H]NBI and 530 ± 40 fmol/mg protein for $[^{3}$H]DPR) and lower affinity $(K_{D}$= 0.35 ± 0.02 nM for $[^{3}$H]NBI and 7.6 ± 0.7 nM for $[^{3}$H]DPR). The adenosine uptake inhibitors are the most potent inhibitors of binding $(K_{i}$ of $10^{−8}-10^{−7}$M) whereas adenosine receptor ligands such as cyclohexyladenosine, 2-chloroadenosine, and various methylxanthines are several orders of magnitude less potent $(K_{i}$ $10^{−5}-10^{−2}$). The inhibition of $[^{3}$H]DPR binding by NBI is biphasic, with only 40% of binding being susceptible to inhibition by NBI concentrations < $10^{−5}$M. The tissue distribution of $[^{3}$H]DPR binding parallels that of $[^{3}$H]NBI although in most cases significantly more sites are observed with $[^{3}$H]DPR. Calcium channel blocking agents such as nifedipine, nimodipine, and verapamil are also inhibitors of $[^{3}$H]DPR binding with potencies in the micromolar range. The data are consistent with $[^{3}$H]DPR being a useful additional ligand for the adenosine uptake site and provide evidence that multiple uptake binding sites exist of which only about 40% are NBI-sensitive. |
| Related Links | https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1471-4159.1987.tb05651.x |
| Ending Page | 1236 |
| Page Count | 6 |
| Starting Page | 1231 |
| e-ISSN | 14714159 |
| DOI | 10.1111/j.1471-4159.1987.tb05651.x |
| Journal | Journal of Neurochemistry |
| Issue Number | 4 |
| Volume Number | 48 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 1987-04-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: Journal of Neurochemistry Medicinal Chemistry -adenosine Uptake Sites Nitrobenzylthio-inosine) |
| Content Type | Text |
| Resource Type | Article |
