This research will investigate behavioral and pharmacological variables that modify the development and expression of tolerance to the behavioral actions of morphine and related opioids. The experimental methods of behavioral pharmacology will be used to identify ways in which the tolerance produced by acute or chronic opioid administration can be manipulated. The behavioral end-points assessed will include effects on ongoing rates and patterns of schedule-controlled behavior, the discriminative stimulus functions of opioids, and the reinforcing functions of opioids. Preliminary studies have found that the initial behavioral consequences of morphine exposure can influence the course of behavioral tolerance development. We will extend these studies by examining behavioral tolerance development under a wider range of pharmacological and environmental conditions. Specific experiments will first assess the rate and degree of the development and loss of behavioral tolerance during chronic osmotic infusions of opioids. Tolerance development will be characterized as a function of the maintenance opioid employed (morphine or etorphine), and its dose and duration of administration. Subsequent studies will assess the degree of cross-tolerance to other opioids, and will evaluate the contributions of behavioral variables (practice factors and the reinforcement consequences of initial morphine exposure) to the rate and degree of tolerance to morphine's rate-altering effects. The roles of pharmacological and behavioral factors in the development of tolerance to the discriminative stimulus properties of morphine will be examined by comparing changes in generalization functions after selected chronic opioid dosing regimens. Similar studies will assess the rate, degree, and specificity of any tolerance to the reinforcing properties of opioids during chronic opioid administration. Such identification of the behavioral consequences of long-term opioid administration, and of the ways such consequences can be modified by both pharmacological and psychological factors, may have implications for our understanding of both of tolerance processes in general and of the factors underlying opiate abuse.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA003796-02
Application #
3208457
Study Section
(SRC)
Project Start
1985-02-01
Project End
1988-01-31
Budget Start
1986-02-01
Budget End
1987-01-31
Support Year
2
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Wayne State University
Department
Type
Schools of Arts and Sciences
DUNS #
City
Detroit
State
MI
Country
United States
Zip Code
48202
Chen, Yukun; Evola, Marianne; Young, Alice M (2013) Memantine and dizocilpine interactions with antinociceptive or discriminative stimulus effects of morphine in rats after acute or chronic treatment with morphine. Psychopharmacology (Berl) 225:187-99
Steinmiller, Caren L; Young, Alice M (2008) Pharmacological selectivity of CTAP in a warm water tail-withdrawal antinociception assay in rats. Psychopharmacology (Berl) 195:497-507
Walker, Ellen A; Young, Alice M (2002) Clocinnamox distinguishes opioid agonists according to relative efficacy in normal and morphine-treated rats trained to discriminate morphine. J Pharmacol Exp Ther 302:101-10
Young, A M (2001) Access conditions are crucial: comment on Lynch and Carroll (2001). Exp Clin Psychopharmacol 9:157-9; discussion 160-2
Walker, E A; Young, A M (2001) Differential tolerance to antinociceptive effects of mu opioids during repeated treatment with etonitazene, morphine, or buprenorphine in rats. Psychopharmacology (Berl) 154:131-42
Zhang, L; Walker, E A; Sutherland 2nd, J et al. (2000) Discriminative stimulus effects of two doses of fentanyl in rats: pharmacological selectivity and effect of training dose on agonist and antagonist effects of mu opioids. Psychopharmacology (Berl) 148:136-45
Walker, E A; Zernig, G; Young, A M (1998) In vivo apparent affinity and efficacy estimates for mu opiates in a rat tail-withdrawal assay. Psychopharmacology (Berl) 136:15-23
Makhay, M M; Young, A M; Poling, A (1998) Establishing morphine and U-50,488H as discriminative stimuli in a three-choice assay with pigeons. Exp Clin Psychopharmacol 6:3-9
Walker, E A; Richardson, T M; Young, A M (1997) Tolerance and cross-tolerance to morphine-like stimulus effects of mu opioids in rats. Psychopharmacology (Berl) 133:17-28
Young, A M; McMullen, W J; Makhay, M M et al. (1996) Behavioral contingencies modulate tolerance to discriminative stimulus effects of morphine. Psychopharmacology (Berl) 125:220-30

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