Blockade of CCK-B receptors by L-365,260 induces analgesia in the squirrel monkey.

The potential antinociceptive effects of the selective cholecystokinin-B (CCK-B) antagonist L-365,260 were examined in the squirrel monkey tail withdrawal test. Pain threshold was measured in 6 male monkeys by recording the latency to remove the tail from a warm (55 degrees C) water bath. L-365,260 at doses of 100 ng/kg to 100 micrograms/kg significantly elevated tail withdrawal latencies throughout a 2 h test period. These data provide the first evidence that blockade of CCK-B receptors induces analgesia in primates.