TY - JOUR T1 - Antinociceptive Effects of Novel A<sub>2B</sub> Adenosine Receptor Antagonists JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 358 LP - 366 DO - 10.1124/jpet.103.056036 VL - 308 IS - 1 AU - Osama M. Abo-Salem AU - Alaa M. Hayallah AU - Andras Bilkei-Gorzo AU - Barbara Filipek AU - Andreas Zimmer AU - Christa E. Müller Y1 - 2004/01/01 UR - http://jpet.aspetjournals.org/content/308/1/358.abstract N2 - Caffeine, an adenosine A1, A2A, and A2B receptor antagonist, is frequently used as an adjuvant analgesic in combination with nonsteroidal anti-inflammatory drugs or opioids. In this study, we have examined the effects of novel specific adenosine receptor antagonists in an acute animal model of nociception. Several A2B-selective compounds showed antinociceptive effects in the hot-plate test. In contrast, A1- and A2A-selective compounds did not alter pain thresholds, and an A3 adenosine receptor antagonist produced thermal hyperalgesia. Evaluation of psychostimulant effects of these compounds in the open field showed only small effects of some antagonists at high doses. Coadministration of low, subeffective doses of A2B-selective antagonists with a low dose of morphine enhanced the efficacy of morphine. Our results indicate that analgesic effects of caffeine are mediated, at least in part, by A2B adenosine receptors. The American Society for Pharmacology and Experimental Therapeutics ER -