Abstract
Signal transduction involving the activation of phospholipase A2 (PLA2) to release arachidonic acid (AA) from membrane phospholipids, when coupled to dopamine D1- and D2-type receptors, can be imaged in rats having a chronic unilateral lesion of the substantia nigra. It is not known, however, if the signaling responses occur in the absence of a lesion. To determine this, we used our in vivo fatty acid method to measure signaling in response to D1 and D2 receptor agonists given acutely to unanesthetized rats. [1-(14)C]AA was injected intravenously in unanesthetized rats, and incorporation coefficients k* for AA (brain radioactivity/integrated plasma radioactivity) were measured using quantitative autoradiography in 61 brain regions. The animals were administered i.v. the D2 receptor agonist, quinpirole (1 mg kg(-1), i.v.), the D1 receptor agonist SKF-38393 (5 mg kg(-1), i.v.), or vehicle/saline. Quinpirole increased k* significantly in multiple brain regions rich in D2-type receptors, whereas SKF-38393 did not change k* significantly in any of the 61 regions examined. In the intact rat brain, D2 but not D1 receptors are coupled to the activation of PLA2 and the release of AA.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call