Effects of acute or chronic administration of novel 3,4-dimethoxyphenylethylamine derivates on anxiety-like behavior.

Novel anxiolytic medications are necessary to broaden treatment therapy. Thus, the aim of the present study was to compare the clinically effective anxiolytic, diazepam with the novel 3,4-dimethoxyphenylethylamine derivates. The novel 3,4-dimethoxyphenylethylamine derivates (PK, 0.1, 1.0, 10.0 mg/kg, i.p.) and diazepam (1.0 mg/kg) were injected acutely or chronically in animals subjected to the black-white model and the open field test. The acute administration of PK-2122 (0.1 mg/kg, i.p.) exerted anxiogenic-like effect, while in the middle or high doses PK-2122 exerted anxiolytic-like effect compared with the control group (p<0.05). The repeated treatment with PK-2111 was followed by anxiolytic-like effect in doses of 0.1 or 1.0 mg/kg which was more significant compared not only with control group, but with comparison to group treated with diazepam (p<0.05). Chronic treatment with PK-2123 or PK-2122 in all tested doses produced anxiolytic-like effect (p<0.05), compared with control group and diazepam group. These results demonstrate that PK-2126, but not PK-2122, is dose independent and may be effective in experimental model of anxiety in rats when administered acutely or repeatedly.