1983 Volume 8 Issue 1 Pages 42-48
This study examined whether the intensity of haloperidol-induced catalepsy in ddY strain mice was modified by repeated administration of haloperidol (HP), using different doses and different intervals. HP was dissolved at the concentration of 1mg/ml of 0.1M tartaric acid and further diluted with a saline solution to administer the volume of 0.1ml per 10g mouse. HP at 0.075, 0.3, 0.6, 1.2, and 4. 8mg/kg were orally administered at three different intervals: daily (successive administration), every 2 and 4 days (intermittent administration), for 21 days. The intensity of catalepsy, namely the duration of time that the mice remain immobile on a horizontal bar, was measured 3 hours after the administration of HP. In repeated administration of HP at 0.075 and 0.3mg/kg no modification was observed for any of the administration intervals. In the case of HP at 1.2 and 4.8 mg/kg, the intensity of catalepsy decreased with the successive administration, on the contrary, it increased in response to the number of administrations with the intermittent administration. The mode of the modification to HP catalepsy varied with the administration intervals, that is, a tolerance developed with the successive administration, whereas a reverse tolerance developed with the intermittent administration.
