Abstract
β-phenylethylamine (PEA), a biogenic trace amine, acts as a neuromodulator in the nigrostriatal dopaminergic pathway and stimulates the release of dopamine. To clarify the mechanism of neurochemical metabolism in attention deficit hyperactivity disorder (ADHD), we measured the urine levels of PEA using gas chromatography-chemical ionization-mass spectrometry. The urinary levels of 3-methoxy-4-hydroxyphenyl glycol (MHPG), homovanillic acid (HVA), and 5-hydroxy-indoleacetic acid (5-HIAA) were determined by high performance liquid chromatography. Urine samples were collected in a 24 hour period.
Findings were compared with those obtained from controls (N=15), children with ADHD (N=15), and children with autistic disorder (AD) (N=5). The mean urinary levels of MHPG, HVA, and 5-HIAA in the children with ADHD were not significantly different from those of the controls or those with AD, whereas PEA levels were significantly lower in children with ADHD (11.23±13.40μg/g creatinine) compared with controls (56.01±52.18μg/g creatinine). PEA and MHPG levels in children with AD (14.75±14.37μg/g creatine, 1.10±0.61μg/mg creatine, respectively) were significantly decreased compared to controls (MHPG, 2.2±0.9μ/mg creatine). The decreased urine PEA in children with ADHD and AD may suggest a common underlying pathophysiology. The decreased urine MHPG in children with AD might indicate the existence of an alteration in central and peripheralnoradrenergic function.
