engleski

Separation anxiety in rat pups with perinatally altered serotonin metabolism

In mammals, serotonin (5HT) is present both in the brain (central compartment) and peripheral tissues (peripheral compartment). 5HT regulates neurodevelopment and as a neurotransmitter mediates essential behaviors including social and anxiety behaviors. Rat pups separated from their mother produce ultrasonic calls which indicate distress from loss of affiliate contact and may serve as a measure of anxiety. Effects of perinatal disturbances in 5HT metabolism were studied by exposing developing Wistar rats to treatments with the immediate 5HT precursor 5‐ hydroxytryptophan (5HTP, 25 mg/kg), which significantly raises only peripheral 5HT concentrations, or the monoamine oxidase inhibitor tranylcypromine (TCP, 2 mg/kg), which significantly elevates 5HT in both compartments, from gestational day 12 until postnatal day (PND) 21. Separation calls were recorded on PNDs 13 and 16. Latency, number and duration of calls were used as measures of anxiety. Frequency of maximal energy was used as a measure of maturation. Increase in separation anxiety and delay in maturation were slight and nonsignificant after 5HTP treatment but strong and significant after TCP treatment. The results indicate that exposure of developing brain to increased 5HT concentrations leads to behavioral abnormalities that were more pronounced after perinatal alteration in both 5HT compartments, indicating that hyperserotonemia alone is not sufficient to cause 5HT‐related disturbances in neurodevelopmental syndromes.

serotonin; ultrasonic vocalizations; hyperserotonemia; tranylcypromine; rats; 5‐ hydroxytryptophan

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