NT5E and Keratoconjunctivitis sicca: In particular, the following therapies may come true in the near future: ATP for depression, AD; ADO for sleep disorders; CD73 for cancer or inflammation; A1 receptor for pain and sleep disorders; A2A receptor for AD and PD; P2X1 receptor for bladder disorder and hypertension; P2X3 receptor for cough and hypertension; P2X7 receptor for cytokine release syndrome, inflammatory disease, brain disorders, and cancer; P2Y2 receptor for dry eye; P2Y12 receptor for pain and inflammation beyond current indications approved by FDA.