Al. Muntoni et al., REPEATED NALTREXONE ADMINISTRATION ACCELERATES RESOLUTION OF MORPHINESOMATIC WITHDRAWAL SIGNS IN MORPHINE-DEPENDENT RATS, European journal of pharmacology, 301(1-3), 1996, pp. 9-10
Morphine-dependent rats were divided into two subgroups. The first was
allowed to develop a spontaneous withdrawal syndrome which was still
present 33 h after the last morphine administration. The second subgro
up received five injections of naltrexone. While the first two injecti
ons of naltrexone precipitated a marked somatic withdrawal syndrome, s
ubsequent naltrexone failed to worsen the somatic signs. 24 h after th
e last morphine administration, naltrexone was completely ineffective.
It is concluded that naltrexone shortens the duration of the morphine
somatic withdrawal signs in dependent rats.