Degenerative changes of neurons in the superior cervical ganglion following an injection of Ricinus communis agglutinin-60 into the vagus nerve in hamsters

Abstract

The present study describes neuronal changes in the superior cervical ganglion of hamsters following injection of Ricinus communis agglutinin-60 (RCA-60) into the ipsilateral vagus nerve in the cervical region. There were no noticeable structural changes in the ganglion 1 day after injection. Between 3 and 15 days after injection, a small number of neurons located in the caudal part of the ganglion underwent degenerative changes including disappearance of rough endoplasmic reticulum and cytoplasmic vacuolation. The structural alterations were most acute 7 days after the injection when some neurons showed signs of total vacuolation and lysis. A second phase of neuronal change occurred after longer survival periods extending from 60 to 120 days after injection. The most striking feature of such neurons was darkening of their dendrites associated with abnormally high density cytoplasm that contained mitochondria with disrupted cristae. As distinct from the early phase in which cell necrosis was observed, there was no evidence of cell death of neurons bearing darkened dendrites. Since examples of exfoliation of the affected dendrites and their phagocytosis by satellite cells were extremely rare, it is postulated that these structural alterations are probably reversible but over an extended period. The significance of the two phases of degenerative change is discussed in connection with the acute and possible chronic effects of the toxic lectin. The present study also confirms the presence of postganglionic sympathetic axons in the cervical vagus nerve.

Ultrastructural changes of posterior lingual glands after hypoglossal denervation in hamsters

“…On the other hand, morphological and electrophysiological studies have provided evidence that some cranial nerves, including trigeminal (Matthews & Robinson, 1980), facial (Thomander et al. 1984; Matthews & Robinson, 1986), vagus (Ling et al. 1990) and hypoglossal (O’Reilly & Fitzgerald, 1990; Fukui et al.…”

Ultrastructural Identification of a Sympathetic Component in the Hypoglossal Nerve of Hamsters Using Experimental Degeneration and Horseradish Peroxidase Methods

“…It is generally accepted that the postganglionic sympathetic fi bers which originate from the superior cervical ganglion (SCG) travel along the nerve plexuses of the internal and external carotid arteries [Bowers and Zigmond, 1979;Marfurt et al, 1986;Tamamaki and Nojyo, 1987;Buller and Bolter, 1997]. Both the morphological and electrophysiological studies have provided evidence to suggest the existence of sympathetic fi bers traveling along some cranial nerves including the vagus and the hypoglossal nerves Robinson, 1980, 1986;Thomander et al, 1984;Ling et al, 1990;O'Reilly and Fitzgerald, 1990;Takeuchi et al, 1993]. In this connection, Fukui et al [1992] had demonstrated the labeling of SCG following the application of horseradish peroxidase (HRP) to the hypoglossal nerve trunk in cats.…”

Effects of Noise Exposure on the Vestibular System: A Systematic Review

“…When examined 4 to 7 days after the blast exposure, ultrastructural analysis using electron microscopy revealed neurons with darkened dendrites (dark appearance of cytoplasm within dendritic processes). Darkened dendrites can indicate that neurons are in an atrophic state due to trauma and have been reported following axotomy and exposure to neurotoxins (37,38). Additionally, microglia at this same time point exhibited morphological changes and proliferation, suggesting a massive inflammatory response mediated by microglia.…”