Etifoxine does not impair muscle tone and motor function in rats as assessed by in vivo and in vitro methods.

The purpose of our study is to evaluate the effects of the translocator protein (TSPO) ligand etifoxine on muscle tone and locomotor activity. In addition, the mechanism of action of etifoxine on the presynaptic membrane and neuromuscular junction is investigated. These effects of etifoxine were examined employing the following methods: 1) in vivo experiments using bar holding test and activity cage test, and 2) comparative in vitro studies with nifedipine on indirectly-elicited twitches of striated abdominal muscle preparations. Etifoxine in doses 50 mg/kg and 100 mg/kg i.p. does not produce any significant changes in locomotor activity and muscle tone of intact rats. Nifedipine (10-5 М) induces a significant decrease in the muscle force of striated muscle preparations. Etifoxine (10-8-10-4 М) has no significant effect on indirectly-elicited twitch tension. Results show that the TSPO ligand etifoxine has no myorelaxant effect. The activation of TSPO is not associated with a reduction in muscle tone and motor impairment. Etifoxine does not affect the presynaptic membrane and its influence on L-type Ca2+-channels is insignificant. Etifoxine does not act as a competitive antagonist of acetylcholine and does not impair the impulse transmission in the neuromuscular junction.

Effects of propolis and CAPE on proliferation and apoptosis of McCoy-Plovdiv cell line.

UNLABELLED: The mechanisms of action of propolis can be studied in detail by comparing the effects of propolis and the effects of its constituent components. AIM: To clarify and compare the effects of Bulgarian propolis and caffeic acid phenethyl ester (CAPE, a chemically synthesized component of propolis)--by using a set of cellular, molecular-biological and immunological techniques. MATERIAL AND METHODS: The McCoy-Plovdiv cell line was treated with propolis and CAPE in increasing concentrations (0.01, 0.1, 1.0, 10 mg/L, and 2.5, 4, 8, 16 mg/L, respectively). The expression of the proliferating cell nuclear antigen (PCNA) and the tumour-suppressor protein p53 was studied immunocytochemically. Apoptosis was measured using a highly sensitive microgel electrophoresis technique (comet assay). RESULTS: The results of the study showed corresponding changes in the expression of the examined proliferative antigens. PCNA was detected in all examined concentrations of the tested substances the expression being dose-dependent. Molecule localization changed from the nucleus to the cytoplasm. Treatment with CAPE brought about gradual attenuation of PCNA expression. High propolis concentrations induced increased synthesis of p53. No p53 expression was found when cells were treated with CAPE. The studied substances in their highest concentrations (10 mg/L propolis and 16 mg/L CAPE) had a cytotoxic effect. The comet assay showed DNA degradation kinetics characteristic for apoptosis. CONCLUSIONS: The present study demonstrates that high concentrations of propolis and CAPE cause apoptosis-induced cell death in McCoy-Plovdiv cells.