1979 Volume 75 Issue 8 Pages 805-828
We studied the influence of differences in strain, sex and drug administration time on physical dependence of morphine and phenobarbital in rats and also whether or not pole climbing avoidance is useful as an indicator of physical dependence. We then compared the behavioral characteristics seen with morphine-dependence with those of other CNS-affecting drugs. Withdrawal signs involving weight loss in morphine and phenobarbital groups were different in JCL-Wistar, SLC-Wistar, JCL-Sprague Dawley and HOS-Donryu strain rats. Withdrawal signs in males were generally more marked than in females. Withdrawal signs due to the difference of drug administration time were different with the sex and/or kinds of drugs. After administration of morphine-type and barbiturate-type drugs, withdrawal signs of sedation and weight loss, also excitability together with weight loss appeared 24 and 40 hours later, respectively. These signs were generally greatly increased by antagonist-induced withdrawal. Abrupt withdrawal of methamphetamine and cocaine caused no withdrawal signs. Rectal temperature was unchanged on abrupt withdrawal in the case of each drug, though temperatures did decrease with morphine-type drugs, and increased with phenobarbital and chlordiazepoxide groups, on antagonist-induced withdrawal. Inhibition of the avoidance was mild with the abrupt withdrawal of morphine, codeine, phenobarbital, chlordiazepoxide and cocaine, but was marked on antagonist-induced withdrawal of morphine and codeine.
