Snake Venoms as an Experimental Tool to Induce and Study Models of Microvessel Damage

The catchwords of this chapter came from a scientist whose significant work covers two fields: pharmacology and experimental pathology. The above motto (Selye, 1964) is thus a true reflection of his doublefold preoccupation, recognizing hereby that basic problems of medicine demand an integral approach from angles of more than one discipline. As two authors of this chapter are pharmacologists and the third an experimental pathologist, the symbolic connection to the above is evident. An even more important bridge between the motto and this chapter is the subject proper to be dealt with: experimental disease models of vascular conditions. It will be shown that a number of snake venoms and purified components thereof can, under specified circumstances, induce vascular changes which in morphology, biochemical pathogenesis, and pharmacologic responsiveness represent models of early phases of tissue injury conditions. The purpose of this article is to describe and discuss several aspects of such models. At the outset, however, it appears useful to briefly speculate on what the characteristics of disease models in general are. Let us start with the realization that a model is never a perfect replica of the original. This is an inherent truism, valid for every model, because if it were not so the model would be identic with the original disease and not its model. Certain models show a phenomenologic resemblance to disease conditions. The danger of such models is that this resemblance may hide the underlying mechanism, thus leading to misinterpretation.