[Effects of intragastric administration of thenorphine on morphine-induced behavioral sensitization in mice].
OBJECTIVE
To investigate the effects of intragastric administration of thenorphine (Then) on behavioral sensitization to morphine (Mor) in mice.


METHODS
Locomotor activity was detected after intragastric administration of thenorphine or co-administration of thenorphine with Mor in mice. Mice were induced to be behaviorally sensitive to Mor, and were given the combination of Mor and thenorphine to observe the effects of thenorphine on the development, transfer and expression of Mor-induced behavioral sensitization.


RESULTS
A single intragastric administration of thenorphine (1.25 - 5.0 mg x kg(-1)) dose-dependently inhibited the locomotor activity in mice (P < 0.01) and the effects of thenorphine on locomotor activity developed tolerance after repeated administration. Co-administration of thenorphine effectively inhibited Mor-induced hyperactivity (P < 0.05) and the development, transfer, expression of Mor-induced behavioral sensitization in mice (P < 0.05 or P < 0.01).


CONCLUSIONS
Thenorphine was shown to suppress the central nervous system and may be effective against the abuse and addiction to opioids.
Zhao
Wen-li
WL
National Institute on Drug Dependence, Peking University, Beijing 100083, China.
Liang
Jian-hui
JH
Gong
Ze-hui
ZH
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002047:Buprenorphine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D005260:Female; D008297:Male; D051379:Mice; D009020:Morphine / Q000037:antagonists & inhibitors*; D009043:Motor Activity / Q000187:drug effects; D011897:Random Allocation
D002492:Central Nervous System Depressants; C497654:thenorphine; D002047:Buprenorphine; D009020:Morphine