Permanent gross demonstration of the conduction tissue in the dog heart with palladium iodide

Abstract

A permanent gross demonstration of dog cardiac conduction tissue was attempted unsuccessfully using standard glycogen and fat stains, experimentally induced lipogenesis, iodine, and the iodides of fluorescein, silver, and lead. Staining with insoluble sulfides was also unsuccessful. Permanent gross differentiation of the tissue can be accomplished with palladium iodide. The best fixative for minimum tissue distortion which still permits good differentiation is neutralized formol-saline. The opened and fixed heart is dipped in alcohol for 15 minutes prior to staining, then placed in an iodine-potassium iodide solution for two to five minutes. It is then rinsed in running water for one minute and transferred to a solution containing PdCln and HC1 and left for ten minutes. Following the staining reaction, a differentiation lasting several hours is necessary. By this method, the entire sub-endo. cardial ramification of the specialized tissue can be permanently demonstrated. Alternatively, the above process may be replaced by painting the endocardium with the various solutions, the results being equivalent but more localized.

Heart

“…A method using palladium iodide is described for the permanent gross demonstration of the conduction (Purkinje) tissue of the dog's heart (174). A functional study utilizing unilaterally sympathectomized dog hearts sug gests that the right cardiac sympathetic nerve goes primarily to the atrial and nodal tissue with a variable distribution to the ventricles while the left cardiac sympathetic nerve goes mainly to the ventricle with a lesser, more variable, supply to the atria (175).…”