A series of pyrazinocarbazoles, analogues of short acting antidepressant pirlindole (2,3,3a,4,5,6-hexahydro-8-methyl-1H-pyrazino[3,2,1-j,k]carbazole hydrochloride), were tested as inhibitors of monoamine oxidase A (MAO-A) and B (MAO-B). Rigid analogues exhibited potent and selective inhibition of MAO-A and have size limits (X:Y:Z) of 13.0 x 7.0 x 4.4 A. Besides MAO-A inhibition flexible analogues also demonstrated potent inhibition of MAO-B and in contrast to rigid analogues their inhibitory activity did not show the dependence on these sizes. The qualitative information (steric and electrostatic coefficients) from the 3D-QSAR with CoMFA models for MAO-A and -B are different, and this information can be used to determine the structural features influencing inhibitor selectivity.

Derivatives of a triazole are used not only as fungicides to prevent infection of plants, but also for treatment. These drugs are actively used against plant diseases caused by basidiomycetes, ascomycetes, and some deuteromycetes. Due to their chemical stability, they have a long-term protective effect, and their solubility in water ensures their movement from the roots to the aerial part of plants. The aim of this work was to study the effect of seed treatment with tebuconazole-containing preparation “Bunker” on the growth of shoots and roots of winter wheat in the light and physiological and biochemical parameters. We used a fungicide of prophylactic and therapeutic action tebuconazole-containing seed treater “Bunker” (August, Russia), the active ingredient of which is tebuconazole (60 g/L). The shoot length and total root length, wet and dry biomass, as well as the content of photosynthetic pigments, reactive oxygen species – hydrogen peroxide (H2O2) and lipid peroxidation products (LPO) reacting with thiobarbituric acid (TBA-RP) in the tissues of shoots and roots were analyzed. The content of chlorophylls a and b and carotenoids in the extract was determined spectrophotometrically at wavelengths of 665, 649, and 440 nm, respectively. The obtained results indicate that the action of the drug is aimed at inhibiting the growth of shoots and reducing the ratio of shoot length to root length, while on the 7-9th day of growth, the effectiveness of its action is higher, and the most significant effect is exerted by an increased dose of the disinfectant (1.5 μL/g). It was found statistically significant stimulation of root growth on the 9th day of cultivation, regardless of the dose of the dressing agent. Despite the significant growth-inhibiting effect, treatment with Bunker was not accompanied by activation of oxidative processes in shoot tissues, with the exception of an increase in the content of H2O2 and TBA-RP at the initial stage of growth (5 days). In root tissues, the content of H2O2 and TBA did not change under the action of the studied preparation. No differences in the content of chlorophylls a and b and carotenoids in the tissues of wheat shoots after treatment with the studied fungicide were found. Based on the data obtained, it can be concluded that seed dressing agents containing tebuconazole as an active ingredient can be used to ensure plant resistance to moisture deficiency and improve mineral nutrition.

The effects of pirlindole and dehydro-pirlindole on GABAA receptors and MAO-A activity were investigated in vitro. Pirlindole was inactive as a GABA antagonist. Dehydro-pirlindole exhibited partial and selective blockade of a subset of GABAA receptors with an EC50 of 12 microM and maximum reversal (delta Bopt) of 42%. Inhibition of rat brain and human placenta MAO-A by both compounds was much more potent (with IC50 range 0.3-0.005 microM). Their effects on MAO-A activity were partially reversible in vitro. In contrast to pirlindole, dehydro-pirlindole may act not only as MAO-A inhibitor but also as a clozapine-like selective GABAA receptor blocker, preferentially blocking a subset of GABAA receptors that are not sensitive to DMCM or Ro 5-4864.

SummaryIntraperitoneal administration ofpirlindo.1e (pirazidole) or 'soluble pirlindole' 50 mg/kg bodyweight prolonged the onset of seizures and decreased the intensity of seizures in rats genetically selected for high sensitivity to aUdiogenic hereditary epilepsy line or selegyline inhibit the activity of both MAO types A and B.Pirlindole interacts with the active site of MAO-A which catalyses oxidative conversion of pirlin-

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