Elsevier

Neuropharmacology

Volume 14, Issue 8, August 1975, Pages 611-614
Neuropharmacology

Persistence of chronic morphine effects upon activity in rats 8 months after ceasing the treatment

https://doi.org/10.1016/0028-3908(75)90129-XGet rights and content

Abstract

Twelve rats were treated daily with 20mgkg of morphine HCl for 59 days and motility was registered for 7 hr after treatment using jiggle-cage actometers. Animals were then tested for the persistence of chronic morphine effect upon activity and were given the same dose of the drug on days 20, 40, 80, 160 and 240 after ceasing the treatment.

The initial depression of motility rapidly underwent tolerance (4–6 days) and then was gradually changed into excitation. This excitation disappeared when animals were tested 20 days after Their last previous morphine injection but the depressive phase was not resumed; motility being at a control level. Similar results were obtained on the other testing days.

Contrarily, a delayed excitatory effect, that increased over the days when morphine was given chronically, remained unchanged when the same dose of morphine was given 8 months after the cessation of chronic treatment.

References (13)

  • M. Babbini et al.

    Some behavioral and EEG effects of a new analgesic agent (viminol) in comparison with morphine in rats

    Eur. J. Pharmac.

    (1973)
  • M. Babbini et al.

    Time-dose relationships for locomotor activity effects of morphine after acute or repeated treatment

    Br. J. Pharmac.

    (1972)
  • J. Cochin

    Factors influencing tolerance to and dependence on narcotic analgesics

  • J. Cochin et al.

    Development and loss of tolerance to morphine in the rat after single and multiple injections

    J. Pharmac. exp. Ther.

    (1964)
  • H.F. Fraser et al.

    Comparative effects of 20 mg of morphine sulfate on nonaddicts and former morphine addicts

    J. Pharmac. exp. Ther.

    (1952)
  • A. Goldstein et al.

    Tolerance to opioid narcotics-1: Tolerance to the “running fit” caused by levorphanol in the mouse

    J. Pharmac. exp. Ther.

    (1969)
There are more references available in the full text version of this article.

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