Social Isolation Increases Risk of Morphine Addiction in Male Rats

Abstract

Background: Drug addiction, especially among adolescents, is one of the major concerns of human society. Identifying factors which predispose an individual to drug -seeking behavior, can be beneficial in reducing risk of addiction in society. Materials and Methods: Forty two adult male Sprague-Dawley rats were divided into four groups: 1) pair 2) isolated 3) pair for biased-CPP (Conditioned Place Preference) test 4) isolated for biased-CPP test. At the end of experiment, rats were assessed for memory, mood, neurogenesis, BDNF (brain derived neurotrophic factor) and MDA (malondialdehyde) levels. In addition, rats in biased-CPP test groups were tested for drug abuse preference. Results: Avoidance memory was markedly impaired in isolated rats. Furthermore, isolated rats demonstrated depressive - behavior and had reduced neurogenesis and BDNF levels. Lipid peroxidation (MDA) was significantly enhanced in isolated rats as compared to paired rats. Rats in isolation spent more time in non-preferred compartment than pair rats during biased-CPP test. Conclusion: Social isolation increases vulnerability to morphine addiction thus, creating socially interactive society can be beneficial in preventing drug abuse.