Distribution and projections of nitric oxide synthase neurons in the rodent superior olivary complex

Abstract

The superior olivary complex (SOC), a group of interrelated brainstem nuclei, sends efferents to a variety of neuronal structures including the cochlea and the inferior colliculus. The present review describes data obtained from rodents providing evidence that the gaseous, short-living neuroactive substance nitric oxide (NO) is produced in the SOC. The NO-synthesizing enzyme neuronal NO-synthase (nNOS) has been localized by means of several methods including histochemistry and immunohistochemistry. Perikarya containing nNOS were found in several nuclei of the SOC. Their largest numbers and percentages of total cells were observed in the medial nucleus of the trapezoid body. Stained terminals were observed mainly in the lateral superior olivary nucleus and in the superior paraolivary nucleus. While retrograde neuronal tracing identified a considerable number of nNOS-immunoreactive neurons as to be part of the olivo-cochlear pathway, the projection patterns of other nNOS-immunoreactive SOC cell groups remain to be investigated. We also review other putative sources of cochlear NO, and discuss the possible role of NO in the lower auditory brainstem and organ of Corti with regard to physiological and pathophysiological mechanisms.

The Cellular and Subcellular Localization of Neuroglobin and Cytoglobin ‐ A Clue to Their Function?

“…The same is true for brain, where, e.g., the cerebellar Purkinje cells very actively produce Ngb under nonpathological conditions (20,21). These cells, however, are negative for NOS-specific NADPH diaphorase activity staining (42) and neither reveal pronounced nNOS-, nor iNOS-IS in normal rat brains (43). In contrast to Ngb, no data exist to date on potential interacting partner molecules of Cygb.…”

Moderately Different NADPH-Diaphorase Positivity in the Selected Peripheral Nerves after Ischemia/ Reperfusion Injury of the Spinal Cord in Rabbit

“…The duration of postfixation longer than 12 h may inactivate the enzyme resulting in diminished or even abolished staining (Reuss and Riemann, 2000). A modification of NADPH-d staining by performing the incubation in the presence of formaldehyde allows for a more specific detection of the histochemical nNOS activity than the conventional method (Grozdanovic et al, 1995).…”

Nitric oxide signalling in the brain and its control of bodily functions

“…The presence of NOS has been described in both the peripheral and the central auditory system; the sensory component of the cochlear tissue, the organ of Corti, consists of both sensory hair cells and supporting cells, spiralling down the cochlear duct. NO was shown to regulate cochlear blood flow and modulate presynaptic transmitter release from inner hair cells via the glutamate/NMDA pathway (Reuss & Riemann, 2000). Actually, NO production was shown to occur in several types of cells in the guinea pig cochlea (including neurons and blood vessels), using the NO‐sensitive dye, 4,5‐diaminofluorescein, thus suggesting that NO may play an important role in the inner ear (see Takumida & Anniko, 2002).…”