Action of carbamazepine (50 mg/kg i.p.) and phenytoin (60 mg/kg i.p.) on the activity of cerebellar neurones was studied in rats under urethane anaesthesia. Carbamazepine markedly decreased the firing frequency of all ten neurones recorded continually before and after drug administration. The same conclusion was reached when a group of 53 cells recorded before drug administration was compared with 48 neurones recorded after carbamazepine administration only. The effects of phenytoin were ambiguous - a decrease as well as an increase in frequency was recorded. The solvent used did not change cerebellar unit activity. Cerebellum cannot be considered as a possible target structure for phenytoin but it might be a target for carbamazepine action.
Treated water from wastewater treatment plants that is increasingly used for irrigation may contain pharmaceuticals and, thus, contaminate soils. Therefore, this study focused on the impact of soil conditions on the root uptake of selected pharmaceuticals and their transformation in a chosen soil–plant system. Green pea plants were planted in 3 soils. Plants were initially irrigated with tap water. Next, they were irrigated for 20 days with a solution of either atenolol (ATE), sulfamethoxazole (SUL), carbamazepine (CAR), or all of these three compounds. The concentrations of pharmaceuticals and their metabolites [atenolol acid (AAC), N1-acetyl sulfamethoxazole (N1AS), N4-acetyl sulfamethoxazole (N4AS), carbamazepine 10,11-epoxide (EPC), 10,11-dihydrocarbamazepine (DHC), trans-10,11- dihydro-10,11-dihydroxy carbamazepine (RTC), and oxcarbazepine (OXC)] in soils and plant tissues were evaluated after harvest. The study confirmed high (CAR), moderate (ATE, AAC, SUL), and minor (N4AC) root uptake of the studied compounds by the green pea plants, nonrestricted transfer of the CAR species into the different plant tissues, and a very high efficiency in metabolizing CAR in the stems and leaves. The results showed neither a synergic nor competitive influence of the application of all compounds in the solution on their uptake by plants. The statistical analysis proved the negative relationships between the CAR sorption coefficients and the concentrations of CAR, EPC, and OXC in the roots (R = –0.916, –0.932, and –0.925, respectively) and stems (R = –0.837, –0.844, and –0.847, respectively).