Abstract
Rats were given the opportunity to drink morphine solution following stabilization at three levels of “passive premedication”. Compared to saline treated controls, premedicated rats consumed more morphine solution, but medication level did not significantly affect morphine intake. Premedicated rats adjusted to a reduction in morphine solution concentration by increasing fluid intake substantially, but nonpremedicated rats did not. When morphine was offered in a vehicle of isotonic saline oral consumption rose sharply in premedicated rats but not in their nonpremedicated counterparts. “Drinker” and “nondrinker” rats were identified on the basis of initial response to oral morphine. Premedication eliminated resistance to morphine drinking, but even at the expense of severe fluid deprivation, nonpremedicated nondrinkers refused morphine throughout the entire experiment.
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References
Deneau, G., Yanagita, T., Seevers, M. H.: Self-administration of psychoactive substances by the monkey. Psychopharmacologia (Berl.) 16, 30–48 (1969).
Miller, N. E.: Effects of drugs on motivation: The value of using a variety of measures. Ann. N. Y. Acad. Sci. 65, 318–333 (1956).
Nichols, J. R.: A procedure which produces sustained opiate-directed behavior (morphine addiction) in the rat. Psychol Rep. 13, 895–904 (1963).
Schuster, C. R., Thompson, T.: Self administration of and behavioral dependence on drugs. Ann. Rev. Pharmacol. 9, 483–502 (1969).
Stolerman, I. P., Kumar, R.: Preferences for morphine in rats: Validation of an experimental model of dependence. Psychopharmacologia (Berl.) 17, 137–150 (1970).
Weeks, J. R., Collins, R. V.: Factors affecting morphine intake in self-maintained addicted rats. Psyehopharmacologia (Berl.) 6, 267–279 (1964).
Wikler, A., Martin, W. R., Pescor, F. T., Eades, C. G.: Factors regulating oral consumption of an opioid (Etonitazine) by morphine-addicted rats. Psychopharmacologia (Berl.) 5, 55–76 (1963).
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Cappell, H., LeBlanc, A.E. Some factors controlling oral morphine intake in rats. Psychopharmacologia 21, 192–201 (1971). https://doi.org/10.1007/BF00403858
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DOI: https://doi.org/10.1007/BF00403858