The Morphology of Stereocilia and their Cross-Links in Relation to Noise Damage in the Guinea Pig

Noise-induced hearing loss leads to anatomic and physiologic changes in primary auditory cortex (A1) and the adjacent dorsal rostral belt (RB). Since acetylcholine is known to modulate plasticity in other cortical areas, changes in A1 and RB following noise damage may be due to changes in cholinergic receptor expression. We used [3H]scopolamine and [18F]flubatine binding to measure muscarinic acetylcholine receptor (mAChR) and nicotinic acetylcholine receptor (nAChR) expression, respectively, in guinea pig A1 and RB 3 weeks following unilateral, left ear noise exposure, and a temporary threshold shift in hearing. [3H]Scopolamine binding decreased in right A1 and RB (contralateral to noise) compared to sham controls across all cortical layers. [18F]Flubatine binding showed a nonsignificant upward trend in right A1 following noise but only significantly increased in right RB and 2 layers of left RB (ipsilateral to noise). This selective response may ultimately influence cortical plasticity and function. The mechanism(s) by which cholinergic receptors are altered following noise exposure remain unknown. However, these data demonstrate noise exposure may differentially influence mAChRs that typically populate interneurons in A1 and RB more than nAChRs that are traditionally located on thalamocortical projections and provide motivation for cholinergic imaging in clinical patient populations of temporary or permanent hearing loss.

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Cross-links between stereocilia in the human organ of Corti

The Journal of Laryngology & Otology ◽

10.1017/s0022215100096237 ◽

1985 ◽

Vol 99 (1) ◽

pp. 11-20 ◽

Cited By ~ 31

Author(s):

Peter H. Rhys Evans ◽

Spiro D. Comis ◽

Michael P. Osborne ◽

James O. Pickles ◽

David J. R. Jeffries

Keyword(s):

Guinea Pig ◽

Hair Cell ◽

Organ Of Corti ◽

Sensory Transduction ◽

Human Organ ◽

Cross Links

AbstractHuman cochleae were fixed in glutaraldehyde, without the use of osmium. Crosslinks were seen between the stereocilia, similar to those we have previously reported for the guinea pig: first, stereocilia of the same row on each hair cell were joined by horizontally-running links; secondly, the shorter stereocilia had pointed tips, each giving rise to a single, vertically-pointing link, which ran upwards to join the adjacent taller stereocilium of the next row. We suggest that distortion of this link is involved in sensory transduction. The links were sparser than had been seen in the guinea pig which may be a reflection of the vulnerability of the links to nonoptimal fixation, and the greater difficulty in producing good fixation in human specimens.

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Cross-links between stereocilia in the guinea pig organ of Corti, and their possible relation to sensory transduction

Hearing Research ◽

10.1016/0378-5955(84)90041-8 ◽

1984 ◽

Vol 15 (2) ◽

pp. 103-112 ◽

Cited By ~ 451

Author(s):

J.O. Pickles ◽

S.D. Comis ◽

M.P. Osborne

Keyword(s):

Guinea Pig ◽

Organ Of Corti ◽

Sensory Transduction ◽

Cross Links

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Cross-links between stereocilia in the guinea pig cochlea

Hearing Research ◽

10.1016/0378-5955(85)90010-3 ◽

1985 ◽

Vol 18 (2) ◽

pp. 177-188 ◽

Cited By ~ 154

Author(s):

D.N. Furness ◽

C.M. Hackney

Keyword(s):

Guinea Pig ◽

Guinea Pig Cochlea ◽

Cross Links

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Decision letter for "The Effect of Optic Nerve Section on Form Deprivation Myopia in the Guinea Pig"

10.1002/cne.24961/v1/decision1 ◽

2020 ◽

Keyword(s):

Optic Nerve ◽

Guinea Pig ◽

Nerve Section

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Effect of Contraceptive Steroids on the Endometrium of Guinea Pig: SEM study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080766 ◽

1977 ◽

Vol 35 ◽

pp. 668-669

Author(s):

Mai M. Said ◽

Ramesh K. Nayak ◽

Randall E. McCoy

Keyword(s):

Guinea Pig ◽

Reproductive Tract ◽

Three Dimensional ◽

Female Reproductive Tract ◽

Human Female ◽

Surface Ultrastructure ◽

Transmission Electron ◽

Sem Study ◽

Uterine Mucosa ◽

Group 1

Burgos and Wislocki described changes in the mucosa of the guinea pig uterus, cervix and vagina during the estrous cycle investigated by transmission electron microscopy. More recently, Moghissi and Reame reported the effects of progestational agents on the human female reproductive tract. They found drooping and shortening of cilia in norgestrel and norethindrone- treated endometria. To the best of our knowledge, no studies concerning the effects of mestranol and norethindrone given concurrently on the three-dimensional surface features on the uterine mucosa of the guinea pig have been reported. The purpose of this study was to determine the effect of mestranol and norethindrone on surface ultrastructure of guinea pig uterus by SEM.Seventy eight animals were used in this study. They were allocated into two groups. Group 1 (20 animals) was injected intramuscularly 0.1 ml vegetable oil and served as controls.

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Ultrastructure and Drug Metabolism in the Developing Guinea Pig

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073131 ◽

1973 ◽

Vol 31 ◽

pp. 538-539

Author(s):

W. Kuenzig ◽

M. Boublik ◽

J.J. Kamm ◽

J.J. Burns

Keyword(s):

Guinea Pig ◽

Metabolic Activity ◽

Animal Species ◽

Adult Animal ◽

Smooth Endoplasmic Reticulum ◽

Fetal Life ◽

Mixed Function Oxidase ◽

Cytochrome P 450 ◽

Microsomal Mixed Function Oxidase ◽

Mixed Function Oxidase Activity

Unlike a variety of other animal species, such as the rabbit, mouse or rat, the guinea pig has a relatively long gestation period and is a more fully developed animal at birth. Kuenzig et al. reported that drug metabolic activity which increases very slowly during fetal life, increases rapidly after birth. Hepatocytes of a 3-day old neonate metabolize drugs and reduce cytochrome P-450 at a rate comparable to that observed in the adult animal. Moreover the administration of drugs like phenobarbital to pregnant guinea pigs increases the microsomal mixed function oxidase activity already in the fetus.Drug metabolic activity is, generally, localized within the smooth endoplasmic reticulum (SER) of the hepatocyte.

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