[Specific and non-specific histamine liberation].

Histamine-liberation occurs mainly from the mast cells and basophils, the sitr of synthesis of histamine, and other intermediary substances such as serotonin, S.T.S.A. The possible causes for this histamine-liberation are numerous and varied. Histamine-liberation of immunological order only represents a particular case in this chapter as a whole. The study quite specifically deals with histamine-legeration provoked by the direct pharmacodynamic action of drug substances, in particular those which are used in anaesthesiology. These substances are numerous and act according to two essential mechanisms: action by diffusion in the region of the histamine carrying cell (the case of substances of low molecular weight), enzymatic action on the cell membrane (the case of substances with high molecular weight). From the standpoint of clinical consequences, discrimination between specific and non-specific histamine-liberation is therefore risky. In practice, in the face of a symptomatology of histamine shock, it is necessary to bear in mind what is known of the pharmacological action of the substances used, and on the other hand not to neglect the resources of the history, and to employ the laboratory tests capable of providing arguments for or against anaphylaxis.