Notes: MIPS521 is an adenosine A1 receptor positive allosteric modulator.{49809} It binds to adenosine A1 receptors (Kb = 11 µM) and enhances adenosine-induced inhibition of forskolin-induced cAMP production in CHO cells expressing recombinant human adenosine A1 receptors when used at concentrations ranging from 0.3 to 30 µM. In vivo, MIPS521 (10 and 30 µg/animal) increases the mechanical paw withdrawal threshold in a rat model of neuropathic pain induced by partial sciatic nerve ligation.