This compound is the product of an enzyme whose six different classes have no sequence or structural homology. This compound can bind to f-channels to increase the pacemaker current. This compound’s intracellular levels increase (-5[1])in response to the activation of Golf (“golf”) in the (*) olfactory system. This compound’s intracellular level increases over 100-fold due to the action of cholera toxin, which subsequently causes excess CFTR activity. This substrate of PDE4 is necessary for the activity of protein kinase A. GS (“G-sub-s”) G proteins increase intracellular levels of this compound. The classic second messenger molecule is, for 10 points, what compound (10[1])produced from ATP by adenylyl cyclase? ■END■ (10[1]0[1])