Computer-aided calculation of dose response curves in behavioral pharmacology by using a nonlinear regression...

In a variety of behavioral pharmacological experiments drug induced graded responses can be recorded even if one animal can be tested only once. In this case the analysis of dose response relationships will be accompanied with theoretical and practical problems additional to those known for dose response curves in single subjects as well as for the all-or-none type of responses. An experimental design was considered where one quantitatively measurable response of each animal tested contributed to an average dose response relationship. Use was made of a four parameter model capable of fitting s-shaped dose response curves over the whole feasible dose range for solving this nonlinear regression problem. Two examples, the dose dependent increased locomotor activity induced by apomorphine and the inhibited locomotor activity after pimozide treatment, were given to demonstrate the use of the method described and to direct the reader's attention to the wide range of its possible applications.