This article may incorporate text from a large language model .(October 2025) |
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Names | |
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IUPAC name 2-Chloro-N6-cyclopentyladenosine | |
Systematic IUPAC name (2R,3R,4S,5R)-2-[2-Chloro-6-(cyclopentylamino)-9H-purin-9-yl]-5-(hydroxymethyl)oxolane-3,4-diol | |
Identifiers | |
3D model (JSmol) | |
Abbreviations | CCPA |
ChEMBL | |
ChemSpider | |
MeSH | 2-chloro-N(6)cyclopentyladenosine |
PubChem CID | |
CompTox Dashboard (EPA) | |
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Properties | |
C15H20ClN5O4 | |
Molar mass | 369.80 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
2-Chloro-N6-cyclopentyladenosine (CCPA) is a specific receptor agonist for the Adenosine A1 receptor. [1] It is similar to N6-cyclopentyladenosine. Initially developed to probe the physiological and pharmacological roles of adenosine receptors, CCPA has become a pivotal tool in cardiovascular and neurological research. Due to CCPA's high affinity for Adenosine A1 receptors, its tritiated derivative [3H]CCPA can be used as a diagnostic tool for detecting the receptors in tissue with low receptor density.
CCPA is chemically characterized by the addition of a chlorine atom at the 2-position and a cyclopentyl group at the N6 position of the adenosine molecule. These modifications enhance its receptor selectivity and binding affinity. The molecular formula of CCPA is C15H19ClN5O4, with a molecular weight of approximately 367.80 g/mol.
CCPA exhibits a high binding affinity for A1 adenosine receptors. In rat brain membranes, it demonstrated a Ki value of 0.4 nM, indicating potent interaction. Its selectivity is underscored by a significantly lower affinity for A2A receptors, with a Ki value of 3,900 nM, reflecting nearly 10,000-fold selectivity for A1 over A2A. [2] [3]
As an A1 receptor agonist, CCPA effectively inhibits adenylate cyclase activity. In rat adipocyte membranes, it achieved an IC 50 of 33 nM, demonstrating its potency. Conversely, its influence on A2A receptors is minimal, requiring much higher concentrations to elicit comparable effects.
Interestingly, while CCPA acts as an agonist at A1 receptors, it functions as a moderate antagonist at human A3 adenosine receptors. Studies using Chinese hamster ovary cells expressing human A3 receptors revealed that CCPA binds with a Ki of 38 nM but does not activate the receptor. Instead, it competitively inhibits the effects of A3 receptor agonists, highlighting its dual role depending on the receptor subtype. [2] [4]
CCPA's selectivity and efficacy make it an invaluable tool in exploring adenosine receptor functions. In cardiovascular studies, it has been employed to investigate A1 receptor-mediated cardioprotective mechanisms, including modulation of heart rate and ischemic responses (Ischemia). In neurological contexts, CCPA aids in elucidating the role of A1 receptors in neurotransmission and neuroprotection. Additionally, its antagonistic properties at A3 receptors provide insights into the complex interplay between different adenosine receptor subtypes.
2-Chloro-N6-cyclopentyladenosine (CCPA) stands out as a potent and selective adenosine A1 receptor agonist with unique antagonistic effects on A3 receptors. [5] Its distinct chemical structure underpins its receptor specificity, rendering it a crucial compound in cardiovascular and neurological research. Ongoing studies continue to uncover its potential therapeutic applications and deepen our understanding of adenosine receptor pharmacology.