ADORA2A and myopia: For example, in contradiction to the predicted results, genetic deletion of the Gs-coupled adenosine A2A receptor (A2AR) and the consequent reduction in cAMP level in fact induces, rather than attenuates, myopia in mice [41].This is accompanied by the finding that A2AR activation by the agonist CGS21680 induces expression of mRNAs for collagens I, III, and V and increases production of soluble collagen in cultured HSFs [41].