Further Studies on Opiate Receptors That Mediate Anti‐nociception: Tooth Pulp Stimulation in the Dog

1 The antinociceptive activities of morphine, codeine and dextropropoxyphene (micro-agonists), buprenorphine and Mr 2034 [(-)5,9-dimethyl-2-(tetrahydrofurfuryl)-2'-hydroxy-6,7-benzomorphan](k-agonists ) have been determined against nociceptive responses to electrical stimulation of the tooth pulp in the conscious dog. 2 Dose-dependent increases in nociceptive threshold were obtained for all of the analgesic drugs tested at doses within their antinociceptive range as determined in nociceptive pressure and chemical tests in rodents.