phenanthrenes and Spasm

1. Naloxone was used to study the antagonism of the analgesic effects of some narcotics (morphine sulphate, levorphanol tartrate, and methadone hydrochloride) and narcotic antagonists (pentazocine, cyclazocine, and nalorphine hydrochloride). The analgesic assay used was the mouse phenylbenzoquinone stretching test.2. The in vivo equivalent of a pA(2) value (apparent pA(2)) for naloxone was determined with each agonist. These values were found to be significantly larger with the narcotics than with the narcotic antagonists.3. The slopes in the apparent pA(2) plots were also found to be significantly different. It was concluded that this difference in slopes was probably not due to a lack of equilibrium in one of the two groups of analgesics.4. The results suggest that the narcotic and the narcotic-antagonist analgesics may inhibit stretching in this assay by interacting either with two different receptors or with the same receptor in a different manner.

Topics: Animals; Bridged-Ring Compounds; Cyclazocine; Furans; Ketones; Levorphanol; Male; Methadone; Mice; Morphine; Nalorphine; Narcotic Antagonists; Pentazocine; Phenanthrenes; Quinones; Receptors, Drug; Spasm

1. The antinociceptive activity of morphine, nalorphine, oxotremorine and eserine has been examined in mice in electroshock and phenylbenzoquinone writhing tests.2. The effectiveness of these drugs alone, in combination with each other, and in combination with the muscarinic antagonist atropine sulphate, and with the narcotic antagonist naloxone has also been investigated.3. In both tests morphine was effective and antagonized by naloxone.4. Nalorphine was active in the phenylbenzoquinone test but only slightly active in the electroshock test: it was antagonized by naloxone in both tests.5. Morphine was potentiated by nalorphine in the phenylbenzoquinone test. but antagonized by it in the electroshock test.6. Oxotremorine was effective in both tests, and was antagonized by atropine sulphate.7. Eserine was active only in the phenylbenzoquinone test, and was antagonized by atropine sulphate.8. Oxotremorine was potentiated by eserine in the phenylbenzoquinone test, but antagonized by it in the electroshock test.9. Crossed agonist and partial agonist experiments produced enhancement.10. No antagonism was seen in the crossed antagonist experiments.11. The similarities between the effects of the two classes of drugs are discussed, and the conclusion drawn that they act by separate mechanisms.

Topics: Analgesia; Animals; Atropine; Bridged-Ring Compounds; Drug Synergism; Electroshock; Furans; Ketones; Mice; Morphine; Nalorphine; Phenanthrenes; Physostigmine; Pyrrolidinones; Quinones; Sensory Receptor Cells; Spasm

Topics: Acetylcholine; Antitussive Agents; Bronchi; Bronchial Diseases; Bronchial Spasm; Cyclopentanes; Disease; Histamine; Histamine Agents; Humans; Naphthalenes; Opium; Phenanthrenes; Spasm