morphinans and Constriction--Pathologic

TRK-820, a new type of 4,5-epoxymorphinan derivative, was investigated in vivo for antinociceptive activities and its selectivity on various opioid receptors in mice. TRK-820 given s.c. or p.o. was found to be 351- and 796-fold more potent than U50,488H with acetic acid-induced abdominal constriction test. The duration of the antinociceptive effect produced by TRK-820 was longer than that produced by mu-opioid receptor agonist morphine or other kappa-opioid receptor agonists. In addition, with four other antinociceptive assays, low temperature hot plate (51 degrees C), thermal tail flick, mechanical tail pressure and tail pinch tests, TRK-820 was also found to be 68- to 328-fold more potent than U-50488H, and 41- to 349-fold more potent than morphine in producing antinociception, as comparing the weight of the different compound. However, TRK-820 was less active in inhibiting the high temperature (55 degrees C) hot plate response. The antinociceptive effects produced by TRK-820 were inhibited by nor-BNI, but not by naloxone or naltrindole (NTI) with the abdominal constriction test, indicating that the antinociception is selectively mediated by the stimulation of kappa-, but not mu- or delta-opioid receptors. Co-administration of TRK-820 with morphine slightly enhanced the antinociception induced by morphine in the mouse hot plate test. On the other hand, pentazocine significantly reduced the morphine-induced antinociception. TRK-820 produced sedation at doses, which are much higher than the doses for producing antinociception. These results indicate that the potent antinociception induced by TRK-820 is mediated via the stimulation of kappa-, but not mu- or delta-opiod receptors.

Topics: Administration, Oral; Analgesics, Non-Narcotic; Analgesics, Opioid; Animals; Constriction, Pathologic; Drug Interactions; Hypnotics and Sedatives; Injections, Subcutaneous; Male; Mice; Morphinans; Motor Activity; Nociceptors; Pentazocine; Receptors, Opioid, kappa; Spiro Compounds

Self-treatment of chronic headache with suppositories containing paracetamol and acetylsalicylic acid may lead to serious complications. We report the radiological features of five cases of rectal stenosis following the use of such suppositories. The role of the double-contrast barium enema in suggesting the diagnosis of this complication of a chronic and often unrecognized self-treatment is emphasized.

Topics: Adult; Analgesics; Barium Sulfate; Constriction, Pathologic; Contrast Media; Enema; Female; Headache; Humans; Morphinans; Pneumoradiography; Rectal Diseases; Rectum; Self Medication; Suppositories