engleski

Effects of perinatal treatment with 5-hydroxytryptophan on rat behavior

Autism is a neurodevelopmental syndrome characterized by disturbances in social interactions, language and communication, and in the presence of stereotyped behaviors and interests. Hyperserotonemia is the most consistent, but still unresolved, serotonin (5HT) related finding in autism. According to one theory, dysregulation of peripheral 5HT homeostasis during fetal development could lead to high concentrations of 5HT in blood, inhibiting development of 5HT neurons and leading to anatomical and functional alterations of the brain, seen in autism. In an attempt to explore the influence of a disturbed peripheral 5HT homeostasis on central 5HT functioning, we have studied the behavior of Wistar rats perinatally treated with 5HT precursor, 5-hydroxytryptophan (5HTP, 25mg/kg, s.c.), from gestational day 13 to post-natal day 21, and compared it with the saline treated group. The return to dam test was conducted on day 17, and the other tests from week 11 through week 13 of age. The 5HTP treated group displayed significant differences from the saline treated group in all examined behaviors. The 5HTP treated pups returned to their mother faster and adult rats showed higher horizontal activity in the open field test than the control rats. In the hole-board test, rats treated with 5HTP poked their noses less frequently into the inner holes, relative to the outer holes, than the saline treated rats. In the social choice test, the 5HTP treated group spent less time exploring a conspecific, relative to exploring an object, than the control group. During the exposure to repeated high-pitched sound, control rats habituated to the noise, while the 5HTP treated rats maintained the same level of startling behavior throughout the test. The results indicate that perinatal treatment with the serotonin precursor has indeed affected brain development and was reflected post-natally in greater locomotor activity, higher level of anxiety, and increased sensitivity to repeated stimulus.

serotonin; 5-HTP; hyperserotonemia; rat; open field; hole-board; social choice

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