Környezetszennyező anyagok hatásának vizsgálata elemi- és komplex idegi folyamatokra = Effect of environmental toxicants on the elementary and complex neuronal processes

A bensultap es fipronil szeles korben alkalmazott, un. masodik generacios rovarolőszer, melyek ligand-vezerelt ioncsatorna receptorokon fejtik ki hatasukat. Vizsgaltuk e ket hatoanyag idegrendszerben kifejtett hatasat, es elemeztuk annak időbeli valtozasat. Neztuk az egyszeri, nagy dozisban, intragasztrikusan alkalmazott rovarolőszerek idegi aktivitasra, valamint a kozvetlen idegsejtekre kifejtett hatast in vitro rendszerekben. Mig a bensultap időlegesen csokkentette az alap ingerelhetőseget, a fipronil epp az ellenkező hatast valtotta ki. Az alvas melysege es a viselkedesmintazat is megvaltozott a kezelest kovető napokban. A bensultap lecsokkentette az Ach kivaltotta aram amplitudojat, az anyag koncentraciojanak es az előkezeles idejenek fuggvenyeben. A deszenzitizacios idő a koncentracio novelesevel nőtt. A fipronil a Lymnaea legzesi halozatat modositotta, megnőttek az inter-spike időintervallumok. A bensultap fiziologias allapotbol kiindulva, ha mar kialakult a rohamtevekenyseg, prokonvulziv hatast fejtett ki. A fipronil serkentette az epileptiform tevekenyseg indukciojat, valamint fokozta a mar kialakult gorcstevekenyseg fenntartasat es terjedeset az emlős agykeregben. A mar gorcstevekenyseget mutato idegrendszer fokozottan volt erzekeny a fipronil kezelesre. | Bensultap and fipronil are widely used second generation insecticides which act on different ligand-gated ion channels. The aim of the present study was to investigate neuromodulatory effects and time- course of these compounds. The effect of single, large dose intragastrically or in vitro directly applied insecticides on mammalian neuronal excitability was tested. While bensultap temporarily decreased the basic neuronal excitability, fipronil caused the opposite effect. Following the treatments both sleep pattern and behavior were affected. The amplitude of currents induced by Ach is decreased by bensultap. The degree of inhibition depends on the preapplication time and the concentration of the chemical. The kinetic parameters of the Ach-induced currents are altered by Bensultap, the desensitization time is increased in a concentration-dependent manner. Our data indicate an elevated seizure susceptibility and higher probability for generalisation of epileptiform activity in the bensultap treated animals. Fipronil facilitates the induction and maintenance of seizure activity and promotes their generalisation in both pretreated and treated animals, although it was less proconvulsive in the pre-treated animals. Rotenone restrained the induction and maintenance of seizure activity in pre-treated animals, in contrary seizure activity was facilitated when rotenone was applied during already ongoing activity.