RELATIONSHIP BETWEEN ANTI‐ACETYLCHOLINE AND ANTI‐TREMORINE ACTIVITY IN ANTI‐PARKINSONIAN AND RELATED DRUGS

Abstract

The anti‐acetylcholine potency of a number of anti‐Parkinsonism drugs and related phenothiazine compounds was determined using the isolated guinea‐pig ileum. The antagonism was assessed by the difference between the pA2 and pA10 values and by log concentration‐response curves for acetylcholine in presence and absence of the antagonists. All compounds except chlorpromazine showed some evidence of competitive antagonism to acetylcholine. The anti‐tremor potency of the compounds was assessed from suppression of Tremorine‐induced tremors in mice. There was a relation between anti‐acetylcholine and anti‐Tremorine potency among the anti‐Parkinsonism drugs, but not among the phenothiazine compounds. Some implications of the findings are discussed in relation to the mode of action of anti‐Parkinsonism drugs. 1962 British Pharmacological Society