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Updated: Apr 11, 2026

A Conditioned Place Preference Protocol for Measuring Incubation of Craving in Rats
Published on: November 6, 2018
Pre-conditioned place preference treatment of chloral hydrate interrupts the rewarding effect of morphine
YongMei Sun1, Wei Zong2, MuRu Zhou3
1Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, PR China; Department of Molecular and Cellular Neurobiology, Center for Neurogenomics & Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands.
Abstract:
The medical use of morphine as a pain killer is hindered by its side effects including dependence and further addiction. As the prototypical μ receptor agonist, morphine's rewarding effect can be measured by conditioned place preference (CPP) paradigms in animals. Chloral hydrate is a clinical sedative. Using a morphine CPP paradigm that mainly contains somatosensory cues, we found that pre-CPP treatment in rats using chloral hydrate for 6 consecutive days could disrupt the establishment of CPP in a U shape. Chloral hydrate had no effect on the body weight of rats. Our results indicate that prior treatment with chloral hydrate can interrupt the rewarding effect of morphine.
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