AChE-staining of type II ganglion cells, processes and terminals in the cochlea of the mustached bat

• Published in: Hearing research Vol. 75; no. 1; pp. 61 - 66
• Main Authors: Xie, D.H., Henson, M.M., Henson, O.W.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.1994; Elsevier
• Subjects: Acetylcholinesterase; Acetylcholinesterase - analysis; AChE; Animals; Biological and medical sciences; Chiroptera; Cochlea - enzymology; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Fundamental and applied biological sciences. Psychology; Hair Cells, Auditory, Outer - cytology; Hair Cells, Auditory, Outer - enzymology; Mustached bat; Neurons, Afferent - cytology; Neurons, Afferent - enzymology; Organ of Corti - cytology; Organ of Corti - enzymology; Spiral Ganglion - cytology; Spiral Ganglion - enzymology; Staining and Labeling; Type II ganglion cells; Vertebrates: nervous system and sense organs; Type II ganglion cells; AChE; Mustached bat; Acetylcholinesterase; Spiral ganglion; Ganglionic neuron; Enzyme; Esterases; Inner ear; Pteronotus parnellii; Organ of hearing; Carboxylic ester hydrolases; Vertebrata; Mammalia; Cochlea; Hydrolases; Chiroptera; Histochemistry
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/0378-5955(94)90056-6

There have been a number of reports showing that ganglion cells of sensory neurons may be stained by traditional acetylcholincsterase (AChE) histochemical techniques commonly used to demonstrate efferent nerve fibers and terminals. AChE-staining has been described for cell bodies in the vestibular and spiral ganglia; staining of peripheral and central processes, however, is rare and the presence of reaction product in afferent terminals has not been reported. The outer hair cells of mustached bats, Pteronotus parnellii, differ from those of most mammals in that they typically have a single, large efferent terminal surrounded by 5–7 small, afferent terminals. In this animal an AChE-positive reaction was found not only in efferent fibers and terminals but also in type II ganglion cells, their peripheral and central processes and in outer hair cell terminals. The stained cell bodies were smaller than the unstained type I ganglion cells and they were much fewer in number. The processes of the stained cells could be followed from the soma. The central processes were dispersed throughout the VIIIth nerve trunk. Stained peripheral processes were evident in the osseous spiral lamina, floor of the tunnel of Corti and first space of Nuel and in the outer spiral plexus along the sides of the outer phalangeal (Deiters') cells. AChE-stained afferent terminals were easy to identify after transection of the crossed olivocochlear bundle (COCB) and subsequent degeneration of large efferent terminals. These results are of interest in that assessments of efferent nerve histochemistry after COCB transection need to recognize the potential contribution of AChE reaction product in afferent terminals. The functional significance of AChE-positive sensory nerves is not known; the positive reaction of the type II neurons does not mean that they are cholinergic.