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5-Hydroxytryptophan and sleep in Down's syndrome
Insights
This study investigated the effects of 5-hydroxytryptophan (5-HTP) on sleep patterns in infants with Down syndrome. While 5-HTP showed short-term effects on eye movements, it did not normalize sleep patterns long-term, though it improved muscle tone and motor behavior.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Infants with Down syndrome (mongoloid infants) often exhibit altered sleep patterns.
- 5-hydroxytryptophan (5-HTP) is a precursor to serotonin, a neurotransmitter implicated in sleep regulation.
Purpose of the Study:
- To investigate the long-term effects of oral 5-HTP supplementation on sleep polygraphy in infants with Down syndrome.
- To analyze the impact of 5-HTP on paradoxical sleep (PS) and eye-movement (EM) density.
Main Methods:
- Polygraphic sleep recordings (EEG, EOG, EMG) were conducted on 6 infants with Down syndrome receiving oral 5-HTP for 12-36 months.
- Oculomotor activity during paradoxical sleep was selectively analyzed, focusing on eye-movement density and frequency.
Main Results:
- Non-treated infants with Down syndrome showed significantly decreased eye-movement density compared to normal infants.
- 5-HTP treatment resulted in normalized eye-movement density in only 2 out of 5 treated infants.
- 5-HTP did not induce long-term changes in eye-movement frequencies, with effects lasting up to 8 days.
Conclusions:
- 5-HTP supplementation did not normalize paradoxical sleep eye-movement patterns in infants with Down syndrome in the long term.
- The primary long-lasting benefits observed were increased muscle tone and improved motor behavior.
- Further research is needed to understand the neurobiological mechanisms underlying sleep disturbances in Down syndrome and the potential therapeutic roles of 5-HTP.
Abstract:
Polygraphic total night sleep electroencephalographic (EEG), electro-oculographic (EOG) and electromyographic (EMG) recordings have been made in 6 mongoloid infants who received oral 5-HTP for periods extending from 12 to 36 months. The doses were adapted to the infants' age and tolerance level. The oculomotor activity of paradoxical sleep (PS) was selectively analysed. The eye-movement (EM) density was significantly decreased in non-treated mongoloids as compared with that of normal age-related infants. Out of the 5-HTP-treated patients, however, the results in only 2 were within the limits for normal age-related infants. 5-HTP failed to induce any long-term differences in the EM frequencies. In fact, the drug had a short-term effect lasting up to 8 days. An increase in muscle tone and an improvement of motor behaviour were the only long-lasting results.