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
Kowaluk, E.A.; Mikusa, J.; Wismer, C.T.; Zhu, C.Z.; Schweitzer, E.; Lynch, J.J.; Lee, C.H.; Jiang, M.; Bhagwat, S.S.; Gomtsyan, A.; McKie, J.; Cox, B.F.; Polakowski, J.; Reinhart, G.; Williams, M.; Jarvis, M.F.
Journal of Pharmacology and Experimental Therapeutics 295(3): 1165-1174
2000
ISSN/ISBN: 0022-3565 PMID: 11082454 Document Number: 516198
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