<prompt> Action of alpha 2 and b1 receptors on adenyl cyclaseStimulate; StimulateStimulate; InhibitInhibit; InhibitInhibit; Stimulate  <response>: Beta receptors are GsPCR -so increase adenyl cyclase activity.alpha 1 -g1 pcr,alpha 2 GiPCR-decrease adenyl cyclase activity Ref: KD Tripathi 8th ed. 