Homo- and heterospecific transplantation of embryonic nerve tissue

Abstract

.same species were made several decades ago [i, 6, 8]. It was then shown by morphological methods that the grafts may take and differentiate in the recipient's brain. A long time after these investigations the second stage began: investigation of grafts with the combined use of morphological, histological, and autoradiographic methods [2, 3, 7, 9, ii, 12]. The results of these investigations showed that blood vessels which provide for normal nutrition grow into the graft, neurons differentiate from neuroblasts, and the architectonics of the structure which was transplanted is formed, with preservation of its biochemical properties. For example, grafts of the raphe nuclei synthesized serotonin, grafts of the septum synthesized acetylcholine [2, 3]. Fibers from the graft can grow toward neighboring structures of the recipient's brain and can also receive afferent connections from them [4, i0, 12]. These facts suggest that the function of injured structures of the recipient's brain can be restored and replaced by a graft. Despite obvious specific difficulties, transplantation into the brain does not meet with the main fundamental difficulty, the problem of rejection of foreign tissue through the action of immune mechanisms. The presence of the bloodbrain barrier in transplantation into the brain theoretically allows transplantation of the tissue not only of another individual, but also of another biological species. The object of the present investigation was to make a comparative experimental study of homo- and heterospecific transplantation of nerve tissue.