ИСТИНА

The remote effects of short (5 min) single hyperthermia (HPT) exposure (41-42 °С) of 14 days old KM rat pups will be presented. This data were obtained in 4 series of experiments (AE seizures, being tested at the age of 1 and 4 months). The heating of animals was performed using either the infrared lamp (series 1, 2 and 4), or (series 3) by placing animals in the thermostat (41 °С). The data were obtained for 85 rats in HPT group (48 males and 37 females) and for 96 control animals (42 males and 54 females). No significant differences between male and female groups in maximal AE seizure intensities were found at the ages of 1 and 4 months in both experimental and control groups and the respective data were pooled. At the age of 1 month part of animals was tested in the elevated plus maze (EPM) and their pain sensitivity thresholds (test tail flick) were determined. At the age of 1 month the animals from the HPT group developed significantly (p<0.01) less intense AE seizures than control rats, while the proportion of animals with most intense seizures was significantly lower in HPT group, and the proportion of rats with lack of seizures in response to sound was higher in treated animals (at the age of 1 month not all KM rats develop maximal AE fit). The postictal catalepsy, which is characteristic for KM rats, was significantly larger in HPT group. The pain sensitivity and elevated plus maze behaviour, tested at 1 month age, revealed significant differences from control group as well, which indicated the increased sensitization to pain in HPT animals together with increase in EPM test indices, which could be regarded as the plausible evidence of changes in anxiety. At the age of 4 months no significant differences between HPT and controls in AE proneness were found. The hyperthermia effects on seizures were previously analysed by other authors groups using status epilepticus model (subthreshold serial kainite or corazol injections), while the HPT effect on AE seizures after the single short term HPT was demonstrated in our study for the first time.