Qualitative Drug Lead Discovery

Introduction We investigate discovery in pharmacology by following and analyzing the progress of research on drugs for Parkinson’s disease at our local pharmacology department. In pharmacology research detailed knowledge of biological processes is used to provide a rationale for a desired biological activity of a drug. This desired activity should cause a decrease in disease symptoms and is called a drug lead. Searching for a lead can be understood as a problem of qualitative reasoning. Knowledge of qualitative causal relations between parameters of a biological system and their pathological perturbations can already be sufficient to find parameters that can decrease perturbations. The search involved is structurally similar to that of abductive reasoning, but has a different search goal. Instead of finding a simple explanation of an observed behavior, the task is to find a minimal parameter influence that causes a desired influence on pathological parameters with minimal side effects.