Ccu1 constant current unit

All experiments on animals were performed in accordance with EU Directive 2010/63/EU for animal experiments and complied with the ARRIVE guidelines. Ethics approval for animal experimentations was obtained from the Local Ethics Committee (Lublin, Poland, approval number: 65/2018). Psychomotor seizures in mice were evoked by current (6 Hz, 0.2 ms rectangular pulse width, 32 mA, 3 s duration) generated by an S48 Square Pulse Stimulator and CCU1 Constant Current Unit (Grass Technologies, West Warwick, RI, USA). After application of ophthalmic anaesthetic (0.5% tetracaine hydrochloride) to the mice corneas, the animals underwent corneal stimulation and were placed separately in plexiglas cages (25 × 15 × 10 cm) for the observation of the presence or absence of psychomotor seizures¹⁷ (link). The animals were administered with increasing doses of TP-10, TP-315, TP-427, and the anticonvulsant activity of each compound was evaluated as the ED₅₀ value (median effective dose of the drug, which protects 50% of mice against convulsions) calculated using the log-probit method of Litchfield and Wilcoxon¹⁸ (link).

Psychomotor seizures were induced by corneal stimulation (0.2 ms rectangular pulse width at 6 Hz frequency, stimulus duration 3 s) with the usage of Grass S48 stimulator and CCU1 constant current unit (Grass Technologies, West Warwick, RI, USA). As in the maximal electroshock seizure threshold test, the 6 Hz seizure threshold test was determined by the “up and down” method (Kimball et al. 1957 (link)) and expressed as the CC₅₀ values (with confidence limits for 95% probability), i.e., as the median convulsive current (in mA) needed to produce psychomotor seizures in 50% of the animals tested. The experimental procedure is described in detail in our earlier studies (Socała et al. 2016 (link)).