engleski

Effects of perinatal treatments with 5-hydroxytryptophan and tranylcypromine on serotonin-related behavior in adult rats

Due to its dual role in brain development and function, serotonin (5HT) mediates many essential behaviors common to all mammals, including exploratory and anxiety-related behavior. The aim of this study was to investigate serotonin-related behavior in adult animals after exposing their developing brains to increased 5HT concentrations using two alternative approaches: by primarily increasing 5HT concentrations in the periphery through treatment with the immediate 5HT precursor, or by altering serotonin metabolism in the brain and periphery through treatment with a non-selective MAO inhibitor. Wistar rats were treated subcutaneously with 5-hydroxytryptophan (5HTP, 25 mg/kg), tranylcypromine (TCP, 2 mg/kg), or saline, from gestational day 13 to post-natal day 21. Adult animals were tested for locomotor activity, exploration and anxiety, social choice and reaction to stressful stimulus. There were no differences in locomotor activity among the groups. 5HTP-treated rats showed significantly increased exploratory activity in a hole-board and spent more time exploring an inanimate object in the social choice test. TCP-treated rats displayed reduced thigmotactic anxiety in a hole-board, reduced freezing behavior in response to stressful stimulus, and decreased social anxiety reflected in more time spent in exploring a conspecific in the social choice test. The results indicate that perinatal treatments with 5HTP and TCP have indeed affected brain development, altering so serotonin-related behavior in adult rats in a way which corresponds to decreased 5HT function: increased exploratory and decreased anxiety-related behavior.

serotonin; exploratory behavior; anxiety-related behavior; 5-hydroxytryptamine; tranylcypromine; rats

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