text: In the hot-plate test in mice, the antinociceptive action of the alpha 2-adrenoceptor agonist, UK 14,304, was abolished by the << alpha 2-adrenoceptor >> antagonist, [[ idazoxan ]], the potent alpha 2A-adrenoceptor antagonist, RX 821002 and the preferential alpha 2A-adrenoceptor antagonist, BRL 44408.