Pharmacological characterization of alcohol and barbital physical dependence in mice.

To confirm our previous finding that the underlying mechanism for the development of physical dependence on alcohol and barbital are fundamentally different from each other, further studies on the effect of drugs that modify neurotransmission on the alcohol and barbital withdrawal signs were carried out in alcohol and barbital dependent mice. Phentolamine, propranolol and methysergide exacerbated the alcohol withdrawal signs but suppressed the barbital withdrawal signs indicating the qualitative difference of the underlying mechanism. Some quantitative differences were also found in the effect of clonidine, prazosin, yohimbine, muscimol and bicuculline. On the other hand, metoprolol, atropine and scopolamine did not affect the withdrawal signs developed in the alcohol and barbital dependent animals at the dose employed in the present experiment. These results indicate that the withdrawal signs that appear in alcohol and barbital dependent animals are the manifestation of functional abnormalities of the nervous system, and alcohol and barbital dependence rely on different mechanisms for their production.