Effects of Neuropeptide Y on Cochlear Blood Flow in Guinea Pigs

Itou, Mari; Ogawa, Kaoru; Inoue, Yasuhiro; Sato, Minako; Kanzaki, Jin

doi:10.1080/000164801316878845

Cited by 2 publications

(1 citation statement)

References 18 publications

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“…It was mentioned that a continuous reduction in cochlear blood flow induced by NPY may play an important role in the pathogenesis of stress-induced sensorineural hearing losses, such as sudden deafness (Itou, Ogawa, Inoue, Sato, & Kanzaki, 2001).…”

Section: Discussionmentioning

confidence: 99%

Neuropeptide Y in Rat Spiral Ganglion Neurons and Inner Hair Cells of Organ of Corti and Effects of a Nontraumatic Acoustic Stimulation

Gomide

Laureano

Silveira

et al. 2009

International Journal of Neuroscience

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Neuropeptide Y (NPY) is an important neuromodulator found in central and peripheral neurons. NPY was investigated in the peripheral auditory pathway of conventional housed rats and after nontraumatic sound stimulation in order to localize the molecule and also to describe its response to sound stimulus. Rats from the stimulation experiment were housed in monitored sound-proofed rooms. Stimulated animals received sound stimuli (pure tone bursts of 8 kHz, 50 ms duration presented at a rate of 2 per second) at an intensity of 80 dB sound pressure level for 1 hr per day during 7 days. After euthanizing, rat cochleae were processed for one-color immunohistochemistry. The NPY immunoreactivity was detected in inner hair cells (IHC) and also in pillar and Deiters' cells of organ of Corti, and in the spiral ganglion putative type I (> or = 1,009 microm(3)) and type II (< or = 225 microm(3)) neurons. Outer hair cells (OHC) showed light immunoreaction product. Quantitative microdensitometry showed strong and moderate immunoreactions in IHC and spiral ganglion neurons, respectively, without differences among cochlear turns. One week of acoustic stimulation was not able to induce changes in the NPY immunoreactivity intensity in the IHC of cochlea. However, stimulated rats showed an overall increase in the number of putative type I and type II NPY immunoreactive spiral ganglion neurons with strong, moderate, and weak immunolabeling. Localization and responses of NPY to acoustic stimulus suggest an involvement of the neuropeptide in the neuromodulation of afferent transmission in the rat peripheral auditory pathway.

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Section: Discussionmentioning

confidence: 99%

Neuropeptide Y in Rat Spiral Ganglion Neurons and Inner Hair Cells of Organ of Corti and Effects of a Nontraumatic Acoustic Stimulation

Gomide

Laureano

Silveira

et al. 2009

International Journal of Neuroscience

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Molecular mechanisms in catecholamine and vestibular periphery-mediated vertigo

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2012

Equilibrium Res

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Catecholaminergic inputs into the inner ear originate from the superior cervical ganglion (SCG). Alpha-adrenergic receptors (ARs) are located around the spiral modular artery and are involved in vasocontraction and cochlear blood flow. Beta 1-ARs in the strial marginal cells and vestibular dark cells have a regulatory role on endolymph production. Beta 2-ARs in the endolymphatic sac also control endolymph absorption. Therefore, stressinduced sympathetic nerve hyperactivity might promote adrenergic effects on the inner ear, resulting in the onset of sudden deafness and/or Meniere's disease.Beta 2-ARs show significant long-lasting up-regulation not only in the affected side of the vestibular ganglion (VG) but also in the healthy side, when a great imbalance exists between bilateral vestibular nuclei (VN) activities. Bilateral simultaneous labyrinthectomies have no significant effects on beta 2-AR expression in VG. This finding suggests that beta 2 -ARs in the VG could play a neuro-plastic role in vestibular compensation. Further studies are needed to elucidate the molecular mechanisms in catecholamine and vestibular periphery-mediated vertigo.

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Effects of Neuropeptide Y on Cochlear Blood Flow in Guinea Pigs

Cited by 2 publications

References 18 publications

Neuropeptide Y in Rat Spiral Ganglion Neurons and Inner Hair Cells of Organ of Corti and Effects of a Nontraumatic Acoustic Stimulation

Neuropeptide Y in Rat Spiral Ganglion Neurons and Inner Hair Cells of Organ of Corti and Effects of a Nontraumatic Acoustic Stimulation

Molecular mechanisms in catecholamine and vestibular periphery-mediated vertigo

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