ISSN:
1440-1681
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
SUMMARY 1. To investigate the hypothesis that some degree of tranquillizer activity is a necessary component of analgesic activity, several narcotic analgesic drugs and narcotic antagonists were tested for their ability to block a conditioned avoidance response in rats, and their actions were compared with those of chlorpromazine and chlordiazepoxide.2. Morphine, oxymorphone, oxycodone and codeine specifically blocked the avoidance response in a dose-dependent manner, in doses comparable with those having antinociceptive action. Neither nalorphine nor naloxone had any significant effect on the avoidance response, but they caused a parallel shift of the dose-response curve of morphine to the right.3. Pentazocine specifically blocked avoidance to about 50% in low and intermediate doses, but the highest dose used blocked both avoidance and escape.4. Chlorpromazine was potent in blocking the avoidance response, and nalorphine did not interfere with this action. Chlordiazepoxide had only a slight effect in blocking the avoidance response.5. Interference with 5-hydroxytryptamine metabolism had no effect on the action of narcotics on conditioned avoidance; this finding is difficult to reconcile with the hypothesis that 5-hydroxytryptamine is involved in the analgesic action of morphine.6. The results are consistent with the hypothesis that tranquillizer action is a necessary component of analgesia and may provide a basis for more complete screening of potential analgesics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1440-1681.1974.tb00571.x
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