APOMORPHINE TOLERANCE AND ITS RELATIONSHIP TO MORPHINE TOLERANCE

¹ Department of Pharmacology, University and Bellevue Hospital Medical College

In the experiments described, evidence is brought forward for the following conclusions:

1. Dogs habituated to apomorphine develop a tolerance to its emetic action but not for other of its stimulant effects.

2. Apomorphine tolerant dogs are tolerant to the emetic action of morphine and morphine tolerant dogs to the emetic action of apomorphine. A cross tolerance between the two drugs in regard to their other action is either absent or very slight.

3. Neither morphine nor apomorphine tolerant dogs are tolerant to the emetic action of pilocarpine.