The role of adenosine A 2 receptors in regulation of pial vessels blood flow in anesthetized morphine dependent rats
Physiology and Pharmacology
Adenosine as a potent vasodilator has a physiological role in regulation of regional cerebral blood flow (rCBF). Method: Laser-D oppler flowmetry technique was used to study pial vessels blood flow responses to adenosine receptors agonists and antagonist. Male Sprague Dawley rats (250-350 g) that were housed in standard conditions were anesthetized with Urethane (1.5 g/kg). Adenosine (general agonist), NECA (A 2A and A 2B receptor agonist) and CGS-21380 (A 2A selective agonist), were used in
... t), were used in absence and presence of A 2A receptors selective antagonist, ZM-243185, in naive and morphine-dependent rats. Results: Adenosine, NECA and CGS-21680 increased pial vessels blood flow in naive and dependent rats dose dependently. These responses were blocked significantly by ZM-243185. Responses of pial vessels to adenosine (10 -4 , 10 -5 and 10 -6 M) and NECA (10 -4 , 10 -5 and 10 -6 M) were increased significantly in morphine-dependent rats in comparison to naive rats. Pial vessels responses to CGS-21680 did not show any significant differences between morphine dependent and naive rats. Conclusion: Based on these results it could be concluded that the role of A 2B receptors in regulation of rCBF in morphine dependent rats is more effective than A 2A receptors.