Kinetic evaluation of platelet monoamine oxidase following relaxation in chronic anxiety.

The effect of relaxation training, utilizing EMG biofeedback, on platelet monoamine oxidase (MAO) activity was examined in patients with a history of chronic anxiety. Anxiety scores and MAO activity were significantly lowered after 4 weeks of therapy. Kinetic studies, using phenylethylamine as substrate, indicated a significant increase of the Km constant while the Vmax showed no significant or consistent variation. It is thought that this phenomenon represents an adaptive response by the individual to maintain a homeostatic level of the biogenic amines.