Serum amino acids as indicators of cerebrospinal neuronal activity in patients with micturition disorders

Our previous study showed that the spinal glycine level in rats was changed by spinal injury or bladder outlet obstruction, and this change was reflected by serum glycine levels. Therefore, we measured the serum glutamate and glycine levels in healthy volunteers and patients with cerebrospinal damage or benign prostatic hyperplasia (BPH) to confirm whether the change of serum amino acid levels was obtained from these patients as well as the animal experiment.

We measured the serum glutamate and glycine levels in 170 healthy controls, 57 patients with cerebrovascular disease (CVD), 68 patients with spinal cord injury (SCI), and 70 patients with BPH. Amino acid levels were compared between the controls and patients, according to gender, level of spinal injury and the type of bladder activity.

In the healthy controls, glutamate levels were higher and glycine levels were lower in men than in women. On group comparison of each gender, there were no differences of glutamate levels. However, glycine levels were lower in male and female SCI patients and BPH patients than in controls. According to the level of spinal injury or the pattern of bladder activity and amino acid levels, there were no relationships among them.

Serum glutamate and glycine levels were not related to the spinal injury level or bladder activity. However, serum glycine levels changed in patients with SCI or BPH patients, so it may be possible to use it as an indicator of spinal glycinergic neuronal activity.