lumbar cerebrospinal fluid levels of 5-hydroxyindoleacetic acid , which are used as indicators of central nervous system serotonergic neuronal activity , were significantly higher in 67 patients with chronic pain and in 32 patients with acute pain ( 23.6 +/- 3.3 and 23.1 +/- 3.8 , respectively ) than in 30 patients ( 8.8 +/- 1.7 ) who had no pain .
C0150055
chronic pain
C0030193
pain