| Description |
Although the safety and efficacy of methadone treatment for heroin addiction have been the subject of intensive research, the effects of methadone on cognitive abilities have received only occasional attention. Similarly, the action of naloxone as a pure narcotic antagonist has been well documented but its effects on cognitive abilities have not been well researched. This study was designed to assess the effects of methadone and naloxone, individually and in combination, on a well-learned task in monkeys. Three stump-tailed macaques were trained to stable baseline performance on a 30 second delayed-response task. Following training each subject received separate doses of 2, 5, and 10 mg. of methadone per kg. body weight along with administrations of placebo followed by .1 mg/kg of naloxone and 10 mg/kg methadone followed by .1 mg/kg naloxone. A placebo-saline administration was also given. All dose sequences were individually randomized on a schedule with three days between administrations. Each monkey served as his own control. Performance was described in terms of response latency and accuracy. Systematic observations of behavior were recorded daily. Only one subject showed consistently significant effects on delayed-response performance due to methadone ingestion. Following discussion of these results we propose improvements in experimental design that might permit a more accurate assessment of drug effects. |
