The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity.

Examination of patients with various forms of anxiety and phobic disorders (according to DSM-4 criteria) demonstrated a considerable shortening of enkephalin half-life and reduced total enkephalinase activity in the blood during generalized anxiety, but not during panic disorders and agoraphobia. This was probably related to low blood concentration of endogenous inhibitors of enkephalin-degrading enzymes in patients with generalized anxiety disorders. Heptapeptide Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro), which attenuates behavioral anxiety reactions and does not cause side effects typical of most anxiolytics, dose-dependently inhibited enzymatic hydrolysis of plasma enkephalin (IC50 15 microM). Selank was more potent than peptidase inhibitors bacitracin and puromycin in inhibiting enkephalinases. These results suggest that high efficiency of Selank in the therapy of anxiety and phobic disorders, including generalized anxiety, is due to its ability to inhibit enkephalin hydrolysis.

Relationship between IFN-gamma production by blood lymphocytes and constitutional personality features of patients with idiopathic mitral valve prolapse.

Psychological testing using Eysenck Personality Inventory and immunological testing of 75 patients with idiopathic mitral valve prolapse revealed low production of interferon-gamma by blood lymphocytes and a correlation between interferon-gamma production and patient's temperament. Low neuroticism and extroversion scores were found in patients with normal interferon-gamma production. High neuroticism score was detected in 82% patients with lowest interferon-gamma production, which refers these patients to a group at high immunological risk and prompts the use of interferon and/or its inductors in complex therapy of these patients.