The role of adenosine A 2 receptors in regulation of pial vessels blood flow in anesthetized morphine dependent rats

Marzieh Hosseini, Sohrab Hajizadeh, Yaghoub Fathollahi, Mojtaba Golmohammadi, Batoul Erfani, Ali Heidarian Pour
2008 Physiology and Pharmacology   unpublished
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
more » ... 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.