Argentophil neuronal perikarya and neurofibrils induced by postmortem trauma and hypertonic perfusates

Abstract

Argentophil neuronal perikarya and perikaryal neurofibrils similar to those illustrated in Ramon y Cajal’s classical studies have in the present investigation been found to be manifestations of the chromophil neuron. Conclusive evidence of such association was obtained by silver impregnation with the Bodian technique of sections previously stained with cresyl violet. Regardless of the fixative used, silver-impregnated neurofibrils were evident when (1) normal tissues were fixed by immersion or unsuccessfully fixed by perfusion, (2) normal tissues were exposed and touched after death but before perfusion with the fixative, or (3) flow of perfusates was compromised by the effect of an experimental procedure, as well as when (4) a hypertonic saline solution was used in the first perfusate. These cytologic peculiarities were still discernible after 24 h of postmortem autolysis following a delay in removal of the brain or in immersion of the exposed brain in the fixative. After immersion fixation, argentophilia and chremophilia occurred ubiquitously in the brain of the newborn guinea pig; however, argentophil neurofibrils were noted in the absence of chromophil neurons in the brain stem of the newborn rat, rabbit and cat. After fixation by perfusion, perikaryal neurofibrils were not impregnated in either newborn or old animals or in animals with facial nerve transection. Affinity for Congo red or bire-fringency, exhibited by neurons with marked neurofibrillary changes in human senile brain atrophy, were absent in the present material. On the basis of the current light-microscopic observations, it is concluded that argentophilia of neuronal perikarya and perikaryal neurofibrils is another manifestation of the chromophil neuron induced by postmortem trauma and of the ocellate neuron elicited by perfusion with hypertonic saline.

Adult Neuroplasticity: More Than 40 Years of Research

“…Instead, it was recognized that the morphological analysis of pyramidal neurons is technically delicate. It became apparent that, after a subject's death, neurons may dramatically change their morphology and turn into “dark neurons” when the brain tissue has not been fixed adequately for the histological analysis [18]. When the chronic stress experiments were repeated under conditions that acknowledged those technical issues, it turned out that stress does not kill neurons, which is definitely a good message for stressed individuals [19].…”

Basophilia, acidophilia and argyrophilia of “dark” (compacted) neurons during their formation, recovery or death in an otherwise undamaged environment

“…It is long known that argyrophilia is also acquired by "dark" neurons (Cammermeyer, 1979). This property has been made use of for their demonstration by three quite different silver staining methods (amino-cupric-silver method of de Olmos, 1969; chemical-development-silver method of Gallyas et al, 1980; physical-development-silver method of Gallyas et al, 1990).…”

Postmortem changes in brain cell structure: a review

“…Biophysically, there is strong evidence that compaction involves rapid loss of a water and a gel-gel phase transition (Kovács et al, 2007). Following this striking change in cell morphology, compacted neurons are not expected to follow the typical changes in oncotic necrosis, although they still will eventually undergo necrosis (Cammermeyer, 1979).…”