Enkephalin mRNA production by cochlear and vestibular efferent neurons in the gerbil brainstem

Ryan, AF; Simmons, DM; Ag, Watts; Lw, Swanson

doi:10.1007/bf00231843

Cited by 38 publications

(18 citation statements)

References 22 publications

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“…Fallon and Leslie (1986) have also reported met-enkephalin-positive staining in cells of the rat MNTB, MSO, and SPN with very weak staining in cells of the ventral LSO. On the other hand, leu-enkephalin and mRNA for its precursor preproenkephalin, have been clearly demonstrated in both rat and gerbil VNTB neurones (Ryan et al, 1991;Wynne et al, 1995), but the association of this peptide with medial olivocochlear neurones or other non-olivocochlear populations is not fully resolved. Ryan et al (1991) combined in situ hybridization with retrograde labeling in gerbil, and reported that about 50% of medial olivocochlear neurones in the VNTB manufactured leu-enkephalin, whereas all LSO neurones were negative for this peptide.…”

Section: Peptides In Soc Neuronesmentioning

confidence: 97%

“…This may reflect the technical problems alluded to earlier in this section, but it may also be complicated by probable species differences. On balance, however, there seems little doubt that at least some neurones of either or both of the lateral and medial olivocochlear systems in a number of species express these peptides as well as synthesizing other neurotransmitters such as CGRP, GABA, and acetylcholine (Altschuler et al, 1983(Altschuler et al, , 1988Abou-Madi et al, 1987;Ryan et al, 1991). A detailed consideration of the neurotransmitters of the olivocochlear pathway is the subject of another review (see Eybalin, 1993) and the many diverse findings relating to peptides in these particular neuronal groups of the SOC will, therefore, not be considered in great detail here.…”

Section: Peptides In Soc Neuronesmentioning

confidence: 98%

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Distribution and possible functional roles of some neuroactive peptides in the mammalian superior olivary complex

Robertson

Mulders

2000

Microsc. Res. Tech.

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Section: Peptides In Soc Neuronesmentioning

confidence: 97%

Section: Peptides In Soc Neuronesmentioning

confidence: 98%

Distribution and possible functional roles of some neuroactive peptides in the mammalian superior olivary complex

Robertson

Mulders

2000

Microsc. Res. Tech.

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“…All contain two types of hair cells (HCs), termed type I and type II. Vestibular HCs receive projections from neurons near the root of the fifth nerve (see, e.g., Deschesne et al, 1984;Ryan et al, 1991a; for review, see Anniko, 1988). Whereas efferent fibers synapse directly on the bases of type II vestibular HCs, they synapse primarily on the afferent calyx surrounding type I HCs (see, e.g., HunterDuvar and Hinojosa, 1984).…”

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confidence: 99%

Developmental expression of ?9 acetylcholine receptor mRNA in the rat cochlea and vestibular inner ear

et al. 1998

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Expression of alpha9 acetylcholine receptor (AChR) mRNA was studied by in situ hybridization in the rat adult and developing cochlea and vestibular inner ear. Alpha9 AChR mRNA was first observed in cochlear hair cells (HCs) at embryonic day 18 (E18), increased markedly after birth, stayed high until postnatal day 10 (P10), and decreased to substantially lower adult levels by P14. High levels of alpha9 AChR mRNA expression were also noted in the developing nonneuronal structures of the inner sulcus, chondrocytes, and/or osteoblasts in the cochlear capsule and interscalar laminae. Both developing and adult bone marrow cells also expressed intense alpha9 AChR mRNA. In the vestibular system, alpha9 AChR mRNA was first observed in HCs at E16 in all sensory epithelia, increased to its highest levels by P0-P4, then decreased slightly to reach adult levels by P10. The results are consistent with the alpha9 AChR subserving efferent neurotransmission to both cochlear and vestibular HCs. The observation of alpha9 AChR mRNA in cochlear HCs 2 weeks prior to functional onset in the cochlea further suggests that expression of this gene is not related to HC activity. The observation of substantial nonneuronal expression of alpha9 AChR mRNA suggests that this receptor also has functions separate from its role in neurotransmission.

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“…On reaching the neuroepithelium of each crista or macula, they provide major innervation of hair cells and afferent terminals. The vestibular efferent neurons are organized as three groups: the larger of the two is a collection of choline acetyltransferase, acetylcholinesterase, calcitonin gene-related peptide (CGRP), and enkephalin mRNA-positive cells, located dorsolateral to the genu of the seventh nerve, ventral and medial to the vestibular nuclei [4, 5], and the smaller group, staining negatively for the above markers, is located immediately ventral to the genu.…”

Section: Introductionmentioning

confidence: 99%

Retrograde Neuron Tracing with Microspheres Reveals Projection of CGRP-Immunolabeled Vestibular Afferent Neurons to the Vestibular Efferent Nucleus in the Brainstem of Rats

Chi¹,

Jiao²,

Liu³

et al. 2007

Neuroendocrinology

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Objective: A new retrograde neuron-tracing technique with microspheres was used to explore the possible innervation of calcitonin gene-related peptide (CGRP)-immunolabeled vestibular afferent neurons in the vestibular efferent immunolabeled nucleus in the brainstem. Methods: 0.1 µl of 5% microfluorospheres was injected into the area of the vestibular efferent nucleus, which is located lateral to the genu of the facial nerve. CGRP immunohistochemistry was processed in serial sections of the brainstem at the facial nerve genu level. Double-labeled neurons with both CGRP immunoreactivity and microfluorospheres were examined with fluorescence and confocal laser microscopy. Results: Three types of labeled neurons were observed: (1) neurons only retrogradely microfluorosphere-labeled that were mainly located in the medial vestibular nucleus, lateral vestibular nucleus, superior vestibular nucleus and parvicellular reticular nucleus on the ipsilateral side of the injection; (2) neurons that were both immunolabeled with CGRP and also retrogradedly labeled with microfluorospheres, indicating that they are CGRP cells projecting to the area of vestibular efferent nucleus, these cells were mainly distributed in the superior vestibular nucleus and dorsal vestibular nucleus, and (3) cells only immunolabeled for CGRP that were scattered extensively in the brainstem. Conclusion: The presented methodical contribution demonstrates the suitability of fluorescein-labeled microspheres for retrograde neuronal tracing. The vestibular nuclei contain numerous afferent neurons that send projections to the vestibular efferent nucleus, some of which are CGRP cells. This afferent innervation provides morphological evidence that the vestibular efferent neurons receive input from the vestibular afferent neurons including CGRP cells. These vestibular primary CGRP afferent neurons may have an influence on vestibular efferent neurons. CGRP acts as an important co-transmitter or modulator in the afferent-mediated activity of vestibular efferent neurons, which in turn affect afferents in the vestibular end organs.

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Enkephalin mRNA production by cochlear and vestibular efferent neurons in the gerbil brainstem

Cited by 38 publications

References 22 publications

Distribution and possible functional roles of some neuroactive peptides in the mammalian superior olivary complex

Distribution and possible functional roles of some neuroactive peptides in the mammalian superior olivary complex

Developmental expression of ?9 acetylcholine receptor mRNA in the rat cochlea and vestibular inner ear

Retrograde Neuron Tracing with Microspheres Reveals Projection of CGRP-Immunolabeled Vestibular Afferent Neurons to the Vestibular Efferent Nucleus in the Brainstem of Rats

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