Detour behavior changes associated with prenatal morphine exposure in 11-day-old chicks

The central nervous system exhibits remarkable plasticity in early life. Prenatal morphine exposure may induce adverse behavioral effects on the neonate and the developing offspring. In the present study, we investigated the effect of prenatal morphine exposure (daily from embryonic days 12-16, 20 mg/kg) on 11-day-old chicks using two forms of spatial paradigms: one trial detour behavior task in which animals must bypass an obstacle to reach the desired goal without any training and detour learning task which required several trials of training to reach the detour criterion. The results showed that, on the condition that chicks could successfully detour in the first trial, morphine exposed chicks exhibited longer detour latency to finish the task, coupled by a preference for turning right versus turning left. In contrast, no significant difference in learning and memory was found in detour learning task between morphine exposed chicks and saline chicks. These findings suggest specific behavioral changes associated with prenatal exposure to opioids during mid to late gestation, also raise attention to the possible health hazard from pregnancy drug use in everyday life. (C) 2010 ISDN. Published by Elsevier Ltd. All rights reserved.

We are grateful to Tao SX, Hu J, Liang YL, Ni Z, Tashi T, Zheng YC, Zhong GH, Mao XL, Liu CL, Ni YA, Lu ZL, (China), Lkhagva B, Badamdorj D (Mongolia), Dorji T (Bhutan), Sherchand L (Nepal), Phuntsog T, Ali M (India), Afzal M, Naqvi AN (Pakistan), Kachkynbaeva K, Cholponkulov T (Kyrgyzstan), and Chekarova I (Russia) for providing samples or assistance in the process of sampling. We thank Dr Miika Tapio and two anonymous reviewers for their critical comments of the manuscript. This study is principally funded by ILRI programme grants from the United Kingdom, Japan, The European Union, Ireland and France, and unrestricted funding from other donors to the CGIAR, and the 973 program of China (2007CB815704), National Natural Science Foundation of China (NSFC) (30771181, 30870295), the West Light Doctoral Program of the Chinese Academy of Sciences, and the Natural Science Foundation of Yunnan province of China (2007C100M). This is ILRI publication IL-200904.