Endogenous δ‐Opioid and ORL<sub>1</sub> Receptors Couple to Phosphorylation and Activation of p38 MAPK in NG108‐15 Cells and This Is Regulated by Protein Kinase A and Protein Kinase CZhe Zhang, Gang Pei, Shunmei Xin et al.|Journal of Neurochemistry|1999Cited by 68