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Urinary 3-methoxy-4-hydroxyphenylglycol sulfate excretion in seventy-three schoolchildren with minimal brain
Insights
Minimal brain dysfunction (MBD) children show lower urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) levels, indicating reduced central norepinephrine activity. Methylphenidate treatment improved MBD symptoms and decreased MHPG excretion.
Area of Science:
- Neuroscience
- Pediatrics
- Biochemistry
Background:
- Minimal brain dysfunction (MBD) is a disorder with unclear mechanisms.
- Previous studies explored urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) in MBD, but findings were inconclusive.
Purpose of the Study:
- To investigate central norepinephrine (NE) function in MBD children by measuring urinary MHPG sulfate (MHPG X SO4).
- To assess the relationship between MHPG X SO4 levels, clinical improvement, and methylphenidate treatment in MBD.
Main Methods:
- Collected 24-hr urine samples from 73 MBD schoolchildren and 57 controls.
- Measured urinary MHPG X SO4 levels.
- Administered methylphenidate to 38 MBD children and analyzed urine samples blindly.
- Observed responses to Chinese herbal medicine in eight MBD children.
Main Results:
- MBD children exhibited significantly lower urinary MHPG X SO4 levels compared to controls.
- Children with marked clinical improvement after methylphenidate showed a significant decrease in MHPG X SO4.
- Non-responders to methylphenidate showed no change or a slight increase in MHPG X SO4.
Conclusions:
- MBD children may have hypoactivity of central norepinephrine (NE).
- This hypoactivity is particularly pronounced in MBD children with a positive family history of genetic factors.
- Urinary MHPG X SO4 levels can serve as a biomarker for NE function and treatment response in MBD.
Abstract:
Although many authors have studied the urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) of minimal brain dysfunction (MBD) children to explore a possible mechanism for this disorder, the mechanism remains unclear. The present study extends the determinations of urinary MHPG X SO4 in MBD schoolchildren to a larger sample to determine whether or not the function of central norepinephrine (NE) of MBD children is normal. 24-hr urinary excretion of MHPG X SO4 was determined in 73 schoolchildren with MBD and 57 normal controls. MGPG X SO4 level was significantly lower in the MBD children than in the control group. 38 of these children received an open trial of methylphenidate and the urine specimen was examined blindly. The children with marked improvement showed significant decrease in urinary MHPD X SO4 while the nonresponders showed no change, but rather a slight increase. This was also demonstrated in a second drug trial in which eight MBD children received Chinese herbal medicine. The authors compare the clinical data with the biochemical findings and point out that the MBD children developed hypoactivity of central NE, especially those with positive genetic factors in their family history.