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Environmental Factors Involved in the Development of Tolerance to Behavioral Effects of Delta-9-Tetrahydrocannabinol

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Annual progress rept. no. 1, Jun 1974-May 1975

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Squirrel monkeys were trained under a variety of behavioral procedures, and then Delta-9-tetrahydrocannabinol was administered daily until tolerance developed. The aim of these experiments is to examine the interaction between behavioral procedures and the development of tolerance to behavioral effects of Delta-9-tetrahydrocannabinol. Three classes of experiments are being performed. The first group of experiments examines the roles of behavioral cost and baseline response rates as determinants of tolerance development. Two complementary experiments in which either high or low rates are compared with moderate response rates are being conducted. In both cases administration of Delta-9-tetrahydrocannabinol results in relatively less loss of reinforcement under conditions where moderate rates prevail than where either the high or low rates prevail. Preliminary results suggest that tolerance develops most rapidly where response rate is low and behavioral cost is high. In the third experiment in this group adequate behavioral control is still being developed. The second group of experiments deals with task complexity. Two experiments comprise this group. One experiment is aimed at examining the interaction of chronic administration of the drug and delay in a memory-type task delayed matching-to-sample, but adequate behavioral control has not been achieved. The other experiment examines the interaction of repeated drug administration with the length of a complex response sequence.

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  • Toxicology
  • Pharmacology

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