Biomedical subjects

C L Wong

Publications and source records attributed to C L Wong.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Effects of ephedrine and phenylpropanolamine on the antinociceptive effects of morphine and codeine in mice.

The effects of ephedrine and phenylpropanolamine on the antinociceptive activities of morphine and codeine were investigated. Both morphine and codeine exhibited dose-dependent antinociceptive activities in the tail flick test. Ephedrine (5, 10 and 20 mg/kg) and phenylpropanolamine (5, 10 and 20 mg/kg) showed no antinociceptive effect when administered alone. The antinociceptive effects of morphine were enhanced in mice pretreated with ephedrine or phenylpropanolamine. similarly, codeine antinociception was increased in mice pretreated with ephedrine or phenylpropanolamine. In all cases, the ED50 values and single dose comparisons were shifted in the same direction. These effects on the antinociceptive potencies of morphine and codeine were found to be dose-dependent, being statistically significant at the higher dose levels of ephedrine and phenylpropanolamine used in the present study.

Analgesics↗

PubMedDate not supplied

The involvement of beta-endorphin in swim-induced antinociception in female mice.

A 30 sec swim in water at 30 degrees C reduced the writhing response produced in the female mice by i.p. acetic acid. Peripherally administered, naloxone and beta-endorphin1-27 antagonized this swim-induced antinociception. However, i.c.v. administration of these compounds had minimal effects on this phenomenon. beta-Endorphin1-27 was effective in antagonizing the antinociceptive effect of beta-endorphin, but not that of morphine. Furthermore, the doses of naloxone required to antagonize the swim-induced antinociception were similar to those required to antagonize beta-endorphin which produced the same degree of antinociceptive response, but were much higher than those required to block the effect of morphine. These results suggest the involvement of beta-endorphin in swim-induced antinociception in female mice and its interaction with some peripheral opioid receptor(s) other than the mu-receptor.

Animals↗

PubMedDate not supplied

The involvement of histamine H2-receptors in restraint-induced antinociception in male mice.

Restraint for 1 h induced significant antinociceptive activity in male mice assessed by the hot-plate test at 55 degrees C. The antinociceptive activity was significant throughout the 1-h period of observation. Prior administration of the histamine H2-receptor agonist dimaprit further enhanced the antinociceptive activity. Furthermore, the induction of antinociception by restraint was antagonized by prior administration of the histamine H2-receptor blocker cimetidine. Similar findings were obtained with another histamine H2-receptor blocker, zolantidine, which supposedly crosses the blood-brain barrier. On the other hand, prior administration of 2-pyridylethylamine, a histamine H1-receptor agonist, or mepyramine, a histamine H1-receptor antagonist, did not affect the development of antinociceptive activity induced by restraint. The doses of histamine receptor agonists and antagonists used in the present study had no effect on the hot-plate response of non-restraint control animals. These results suggest that histamine H2-receptors may be involved in the restraint-induced antinociceptive activity in mice.

Animals↗