Behavioural effects of a subconvulsive dose of kainic acid in rats

Kainic acid can induce a continuum of non-convulsive seizures characterised by epileptic automatisms and convulsive motor seizures depending on the do se. There are scarce data on the behavioural effects of low doses of kainat e inducing only non-convulsive seizures. Therefore, we studied spontaneous behaviour of adult male rats using a method of positive habituation based o n a detailed analysis of patterns and attention of animals to a stimulus ob ject. Twenty-three animals were individually tested in the experimental are na on two consecutive days. Comparing the data from the first two exposures , a conspicuous habituation in all animals was observed. On experimental da y 3, 12 rats received kainate (6 mg/kg intraperitoneally) and the remaining 11 animals received a physiological saline. After 1 h, animals were put in to the arena with an object localised in the centre. It was found that both kainate and saline treated animals exhibited a significant increase in the total number of central area visits, and both the total and mean time spen t in the vicinity of the object. However, the mean time spent was significa ntly shorter in kainate treated rats. Furthermore, kainate rats exhibited a significant decrease in rearing as compared with the controls. In addition , an epileptic automatism (wet dog shakes) was observed in seven out of 12 animals given kainate. The comparison of transition matrices between consec utive behavioural categories showed significant differences between the kai nate and control groups. Our results demonstrate that a non-conculsive dose of kainate induced changes in the structure of spontaneous behaviour and i mpaired the processes related to maintenance of attention. (C) 1999 Elsevie r Science B.V. All rights reserved.