Effects of most perspective compounds — derivatives of 4-thiazolidinones — Les-1205 — ethyl ester of ([2,4-dioxo-5-(thiazol-2-ylkarbamoylmethyl)-thiazolidin-3-yl]-acetic acid and Les-2658 — (5-(-nitrobenzyliden)-2-(thiazol-2-imino)-4-thiazolidinone spectral power of electrocorticogramm registered in frontal and occipital brain cortex of pentylenetetrazol (PTZ) — kindled rats have been investigated. Both drugs were dosages: Les-1205 — 156,3 and 31,3 mg/kg, i. p. and Les-2658 — 235.2 and 47.0 mg/kg, i. p. in 30 min before PTZ administration. Their effects were compared with such ones induced by diazepam (2.7 mg/kg, i. p.). The dosage-depended decrease of spectral power of delta activity along with the increase of gamma and beta rhythm activity in both cortical zones have been registered after Les — 1205 administration in a dosage of 156,3 mg/kg, i. p., and effect was comparable with siuch one induced by diazepam (2.7 mg/kg, i. p.). The increase of high-frequency oscillations in occipital cortex was observed after Les-2658 administration in a dosage of 235.2 mg/kg, i. p.
