Increased risk of developing schizophrenia in animals exposed to cigarette smoke during the gestational period

- Cigarette smoke exposure in pregnant dams caused damage in offspring in adult age.
- Administration of ketamine and ketamine plus cigarette increased the locomotor activity.
- Administration of ketamine reproduced the negative symptoms of schizophrenia.
- Ketamine increased AchE activity in the brain structures.
- Cigarette smoke exposure increases the damage caused by ketamine administration alone.

Cigarette smoking during the prenatal period has been investigated as a causative factor of obstetric abnormalities, which lead to cognitive and behavioural changes associated with schizophrenia. The aim of this study was to investigate behaviour and AChE activity in brain structures in adult rats exposed to cigarette smoke during the prenatal period. Pregnant rats were divided into non-PCSE (non-prenatal cigarette smoke exposure) and PCSE (prenatal cigarette smoke exposure) groups. On post-natal day 60, the rats received saline or ketamine for 7 days and were subjected to behavioural tasks. In the locomotor activity task, the non-PCSE + ketamine and PCSE + ketamine groups exhibited increased locomotor activity compared with the saline group. In the social interaction task, the non-PCSE + ketamine and PCSE + ketamine groups exhibited an increased latency compared with the control groups. However, the PCSE + ketamine group exhibited a decreased latency compared with the non-PCSE + ketamine group, which indicates that the cigarette exposure appeared to decrease, the social deficits generated by ketamine. In the inhibitory avoidance task, the non-PCSE + ketamine, PCSE, and PCSE + ketamine groups exhibited impairments in working memory, short-term memory, and long-term memory. In the pre-pulse inhibition (PPI) test, cigarette smoke associated with ketamine resulted in impaired PPI in 3 pre-pulse (PP) intensity groups compared with the control groups. In the biochemical analysis, the AChE activity in brain structures increased in the ketamine groups; however, the PCSE + ketamine group exhibited an exacerbated effect in all brain structures. The present study indicates that exposure to cigarette smoke during the prenatal period may affect behaviour and cerebral cholinergic structures during adulthood.