ABT-702 (4-amino-5-(3-bromophenyl)-7-(6-morpholino-pyridin- 3-yl)pyrido[2,3-d]pyrimidine), a novel orally effective adenosine kinase inhibitor with analgesic and anti-inflammatory properties. II. In vivo characterization in the rat

J Pharmacol Exp Ther. 2000 Dec;295(3):1165-74.

Abstract

Adenosine kinase (AK; EC 2.7.1.20) is a key intracellular enzyme regulating intra-and extracellular concentrations of adenosine (ADO), an endogenous neuromodulator, antinociceptive, and anti-inflammatory autocoid. AK inhibition provides a means of potentiating local tissue concentrations of endogenous ADO, and AK inhibitors may have therapeutic potential as analgesic and anti-inflammatory agents. The effects of ABT-702, a novel, potent (IC(50) = 1.7 nM), and selective non-nucleoside AK inhibitor were examined in rat models of nociception and acute inflammation. ABT-702 was orally effective and fully efficacious to suppress nociception in a spectrum of pain models in the rat, including carrageenan-induced thermal hyperalgesia, the formalin test of persistent pain, and models of nerve injury-induced and diabetic neuropathic pain (tactile allodynia after L5/L6 spinal nerve ligation or streptozotocin injection, respectively.) ABT-702 was especially potent at relieving inflammatory thermal hyperalgesia (ED(50) = 5 micromol/kg p.o.). ABT-702 was also effective in the carrageenan-induced paw edema model of acute inflammation (ED(50) = 70 micromol/kg p.o.). The antinociceptive and anti-inflammatory effects of ABT-702 were blocked by selective ADO receptor antagonists, consistent with endogenous ADO accumulation and ADO receptor activation as a mechanism of action. The antinociceptive effects of ABT-702 were not blocked by the opioid antagonist naloxone. In addition, ABT-702 showed less potential to develop tolerance to its antinociceptive effects compared with morphine. ABT-702 had no significant effect on rotorod performance or heart rate (at 30-300 micromol/kg p.o.), mean arterial pressure (at 30-100 micromol/kg p.o.), or exploratory locomotor activity (at </=10 micromol/kg p.o.). Thus, ABT-702 is a novel, non-nucleoside AK inhibitor, with a nonopioid, non-nonsteroidal anti-inflammatory drug mechanism of action, which shows antinociceptive and anti-inflammatory activity in vivo.

MeSH terms

  • Adenosine Kinase / antagonists & inhibitors*
  • Administration, Oral
  • Analgesics, Non-Narcotic / pharmacology*
  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Diabetes Mellitus, Experimental / physiopathology
  • Edema / drug therapy
  • Enzyme Inhibitors / pharmacology*
  • Formaldehyde
  • Hemodynamics / drug effects
  • Hyperalgesia / drug therapy
  • Male
  • Morpholines / pharmacology*
  • Motor Activity / drug effects
  • Pain / drug therapy
  • Pyrimidines / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Purinergic P1 / drug effects
  • Streptozocin

Substances

  • Analgesics, Non-Narcotic
  • Anti-Inflammatory Agents, Non-Steroidal
  • Enzyme Inhibitors
  • Morpholines
  • Pyrimidines
  • Receptors, Purinergic P1
  • Formaldehyde
  • ABT 702
  • Streptozocin
  • Adenosine Kinase