RT Journal Article
SR Electronic
T1 A SIMPLE METHOD FOR PRODUCING TOLERANCE TO DIHYDROMORPHINONE IN MICE
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 149
OP 154
VO 140
IS 2
A1 Shuster, Louis
A1 Hannam, Ruth V.
A1 Boyle, William E.
YR 1963
UL http://jpet.aspetjournals.org/content/140/2/149.abstract
AB Mice became tolerant within a few days to the analgesic and exciting effects of narcotics as a result of drinking dilute evaporated milk containing dihydromorphinone HCl (Dilaudid). Tolerant mice could be maintained in good physical condition for 1 month or more while drinking between 50 and 70 mg per kg of dihydro-morphinone HCl daily. When tolerant mice were withdrawn they lost as much as 15% of their body weight over-night, indicating that physical dependence was established. The extent of tolerance increased with increasing daily intake of dihydromorphinone and with the length of time, up to about 7 days, that animals were maintained on one given dose. Mice made tolerant by drinking dihydromorphinone showed decreased excitability. This was manifested by decreased spontaneous activity and a decreased response to the exciting effects of morphine, meperidine, codeine, cocaine, and, to a lesser extent, d-amphetamine. There was tolerance to the analgesic effects of morphine, meperidine and cocaine. The assay, by means of a photoelectric counter, of motor activity following a test dose of narcotic is a sensitive and convenient method for measuring narcotic tolerance in mice.