Studies on Passive Anaphylaxis of Isolated Guinea Pig Intestine Part III The Desensitization by Antigen and Various Kinds of Chemicals, and The Suppressive Action by Benadryl

At the experiment of the passive intestine Schulz-Dale reaction in guinea pig, the actions of antigen, histamine and acetylcholine were compared each other on the desensitization and suppression by benadryl. The results are as follows: 1). Desensitization is established by antigen but not by acetylcholine. It seems that desensitization sometime is established by histamine. 2). Suppressive action by benadryl in its critical concentration shows that antigen is nearer to histamine than acetylcholine. 3). Benadryl concentration in order to abate contracted intestine is the same as in the case of contraction by antigen and histamine but needs higher concentration for the contraction by acetylcholine.