Two groups of facts have been established in previous drug development studies of the non-benzodiazepine anxiolytic fabomotizole. First, fabomotizole prevents stress-induced decrease in binding ability of the GABA_A receptor’s benzodiazepine site. Second, fabomotizole is a Sigma1R chaperone agonist, and exposure to Sigma1R antagonists blocks its anxiolytic effect. To prove our main hypothesis of Sigma1R involvement in GABA_A receptor-dependent pharmacological effects, we performed a series of experiments on BALB/c and ICR mice using Sigma1R ligands to study anxiolytic effects of benzodiazepine tranquilizers diazepam (1 mg/kg i.p.) and phenazepam (0.1 mg/kg i.p.) in the elevated plus maze test, the anticonvulsant effects of diazepam (1 mg/kg i.p.) in the pentylenetetrazole-induced seizure model, and the hypnotic effects of pentobarbital (50 mg/kg i.p.). Sigma1R antagonists BD-1047 (1, 10, and 20 mg/kg i.p.), NE-100 (1 and 3 mg/kg i.p.), and Sigma1R agonist PRE-084 (1, 5, and 20 mg/kg i.p.) were used in the experiments. Sigma1R antagonists have been found to attenuate while Sigma1R agonists can enhance GABA_ARs-dependent pharmacological effects.

This study deals with participation of isoquinoline derivatives of coumarin in the peroxidase reaction catalyzed by the cytochrome c–cardiolipin complex. We have studied coumarin derivatives called coumarin-314 (C-314), coumarin-334 (C-334) and coumarin-525 (C-525). These substances are considered as specific physical activators of chemiluminescence, which accompanies the lipid peroxidation reaction. In the course of the scientific research, a spectrophotometric study of the effect of methanol on the structure of cytochrome c was performed, the optical properties of these substances were studied in the medium of a phosphate buffer, and a spectrophotometric study was performed with parallel registration of the chemiluminescence of a mixture in which cytochrome c catalyzed by a complex with cardiolipin lipoperoxidase reaction in the presence of isoquinolysin derivatives of coumarin. The conclusions of this work contain identification of the reversibility of the action of methanol on the structure of cytochrome c, which proves the possibility of using this alcohol in the study of this protein, the positions of absorption maxima and corresponding values of molar absorption coefficients in the medium of 20 mM phosphate buffer (pH = 7.4) for C-314 (λ_max = 447.5 nm; ε = 32360.4 L/(mol cm)), C-334 (λ_max = 460 nm; ε = 44 012 L/(mol cm)), and C-525 (λ_max = 460 nm; ε = 32 703.56 L/(mol cm)). We also demonstrated that the said substances are substrates of cytochrome c/cardiolipin complex-catalyzed peroxidase reaction. Mass flow of these substances during an average statistical experiment in measurement of chemiluminescence (322 s) for C-314, C-334 and C-525 amounted to 31.89, 37.61 and 25.94%, respectively.