Low frequency electromagnetic radiation and hearing

2009 ◽  
Vol 123 (11) ◽  
pp. 1204-1211 ◽  
Author(s):  
J Morales ◽  
M Garcia ◽  
C Perez ◽  
J V Valverde ◽  
C Lopez-Sanchez ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Electromagnetic Fields ◽  
Control Animal ◽  
Guinea Pigs ◽  
Low Frequency ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Morphological Alteration ◽  
Electric Response ◽  
Hearing Level

AbstractObjective:To analyse the possible impact of low and extremely low frequency electromagnetic fields on the outer hairs cells of the organ of Corti, in a guinea pig model.Materials and methods:Electromagnetic fields of 50, 500, 1000, 2000, 4000 and 5000 Hz frequencies and 1.5 µT intensity were generated using a transverse electromagnetic wave guide. Guinea pigs of both sexes, weighing 100–150 g, were used, with no abnormalities on general and otic examination. Total exposure times were: 360 hours for 50, 500 and 1000 Hz; 3300 hours for 2000 Hz; 4820 hours for 4000 Hz; and 6420 hours for 5000 Hz. One control animal was used in each frequency group. The parameters measured by electric response audiometer included: hearing level; waves I–IV latencies; wave I–III interpeak latency; and percentage appearance of waves I–III at 90 and 50 dB sound pressure level intensity.Results:Values for the above parameters did not differ significantly, comparing the control animal and the rest of each group. In addition, no significant differences were found between our findings and those of previous studies of normal guinea pigs.Conclusion:Prolonged exposure to electromagnetic fields of 50 Hz to 5 KHz frequencies and 1.5 µT intensity, produced no functional or morphological alteration in the outer hair cells of the guinea pig organ of Corti.

Dissociation between the calcium-induced and voltage-driven motility in cochlear outer hair cells from the waltzing guinea pig

1993 ◽  
Vol 104 (4) ◽  
pp. 1137-1143
Author(s):  
B. Canlon ◽  
D. Dulon
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Guinea Pigs ◽  
Outer Hair Cell ◽  
Calcium Ionophore ◽  
Organ Of Corti ◽  
Length Change ◽  
Outer Hair Cells ◽  
Permeabilized Cells ◽  
Length Changes

The waltzing guinea pig, possessing an hereditary progressive deafness, shows pathology to the actin-bearing structures within the hair cells of the organ of Corti. In particular, the affected structures include the stereocilia, the cuticular plate and, as shown in the present study, swollen and disorganized subsurface cisternae. To test whether this pathology affected outer hair cell motility, cells were isolated from waltzing guinea pigs and their age-matched controls and were subjected to either electrical or chemical stimulation. Visual detection thresholds and the magnitude of the electrically-induced length changes were equivalent for both groups. However, when intracellular calcium was increased with either the calcium ionophore, ionomycin or Ca2+/ATP (under permeabilized conditions with DMSO), length changes were significantly reduced for the outer hair cells from waltzing guinea pigs compared to the controls. The average percent length increase induced by 10 microM ionomycin for the outer hair cells from control animals was 2.3 +/- 1.7 whereas for postnatal day 4 waltzing guinea pigs it was 1.3 +/- 1.7. Postnatal day 7 and 10 waltzing guinea pigs responded with significantly smaller percent length changes. The intracellular concentration of ionic calcium increased similarly for both groups after the application of ionomycin as revealed with the indicator fluo-3. In the permeabilized cells in the presence of Ca2+/ATP, control cells responded with a percent length change of 3.5, whereas, age-matched waltzing outer hair cells responded with barely detectable length changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Innervation of the Cochlea of the Guinea Pig by Use of the Golgi Stain

1975 ◽  
Vol 84 (4) ◽  
pp. 443-458 ◽  
Author(s):  
Catherine A. Smith
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Guinea Pigs ◽  
Basilar Membrane ◽  
Organ Of Corti ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Single Row ◽  
Golgi Stain ◽  
Branching Patterns

Nerve fibers with distinctive branching patterns have been demonstrated in guinea pigs by use of the Golgi stain. The cochlear nerve fibers in the basal turn tend to supply a limited segment of the basilar membrane and have most endings on a single row of hair cells. The efferent olivocochlear nerve fibers ramify in a manner which varies from base to apex. Some efferents which terminate on outer hair cells also give branches which course in the inner spiral bundle. Other nerve fibers were studied in the spiral lamina which did not penetrate into the organ of Corti.

Animal Model for the 4-kHz Tonal Dip

1978 ◽  
Vol 87 (4_suppl) ◽  
pp. 1-16 ◽  
Author(s):  
William W. Clark ◽  
Barbara A. Bohne
Keyword(s):  
Hair Cells ◽  
Noise Exposure ◽  
Low Frequency ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Center Frequency ◽  
Auditory Function ◽  
Behavioral Measures ◽  
High Frequencies ◽  
Different Types

In humans, noise exposures produce permanent hearing losses which usually begin at 4 kHz. In chinchillas, a similar pattern of hearing loss was observed following exposure for 9 or 18 days to an octave band of noise with a center frequency of 0.5 kHz. Histopathological observations of cellular degeneration showed that this exposure produced different types of damage in the basal and apical turns of the cochlea. Behavioral measures of auditory function showed that damage in the basal turn was associated with permanent threshold shifts for one to several of the high frequencies. However, moderate losses of outer hair cells commonly appeared in the apical turn without permanent threshold shifts for low-frequency tones. These findings indicate that the pure-tone audiogram may not accurately reflect the condition of the organ of Corti after noise exposure.

Permanent Threshold Shift and Cochlear Hair Cell Loss in the Kanamycin-Treated Guinea Pig

1978 ◽  
Vol 86 (6) ◽  
pp. ORL-886-ORL-887 ◽  
Author(s):  
Cynthia A. Prosen ◽  
Michael R. Petersen ◽  
David. B. Moody ◽  
William C. Stebbins ◽  
Joseph E. Hawkins
Keyword(s):  
Guinea Pig ◽  
Hair Cell ◽  
Hair Cells ◽  
Guinea Pigs ◽  
Cell Loss ◽  
Outer Hair Cells ◽  
Hair Cell Loss ◽  
Hearing Sensitivity ◽  
Cochlear Hair Cell ◽  
Differential Contribution

The differential contribution of the inner hair cells (IHC) and the outer hair cells (OHC) in the mammalian cochlea to hearing sensitivity was assessed in six behaviorally-trained guinea pigs by comparing audiograms preadministration and postadministration of kanamycin, an antibiotic that predominantly destroys guinea pig OHC while leaving the IHC structurally unchanged. The results support the hypothesis that only the IHC of the cochlea responds to tones approximately 50 to 60 dB above the threshold of the intact cochlea.

Effects of Extremely Low Frequency Electromagnetic Fields on Testes in Guinea pig

2007 ◽  
Vol 10 (24) ◽  
pp. 4519-4522 ◽  
Author(s):  
Sanaz Alivandi F ◽  
Samad Zare . ◽  
Hussein Hayatgeibi . ◽  
Ali Qadiri .
Keyword(s):  
Guinea Pig ◽  
Electromagnetic Fields ◽  
Low Frequency ◽  
Extremely Low Frequency

Localization of the P2Y4 Receptor in the Guinea Pig Organ of Corti

2003 ◽  
Vol 14 (06) ◽  
pp. 286-295
Author(s):  
Margarett S. Parker ◽  
Nkeiruka N. Onyenekwu ◽  
Richard P. Bobbin
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Staining Pattern ◽  
Organ Of Corti ◽  
Staining Intensity ◽  
Protein Band ◽  
Outer Hair Cells ◽  
Metabotropic Receptor ◽  
Single Protein ◽  
P2y4 Receptor

Cochleae of guinea pigs were evaluated for the presence of the metabotropic receptor, P2Y4. Evidence is presented that P2Y4 protein is expressed in the guinea pig cochleae using Western blot analysis. A single protein band of 35 kDa was detected with P2Y4 receptor-specific antibody. The cellular distribution of P2Y4 purinoceptor protein was determined by immunohistochemistry of the whole organ of Corti. Immunoreactive staining for P2Y4 was seen in most cells of the organ of Corti. Staining of Hensen's cells and Deiters' cells, especially the outer Deiters' cells, was more intense than staining of the outer hair cells, inner hair cells, and pillar cells. Staining intensity was greatest at the basal turn and progressively decreased in the upper turns with the apex showing the weakest staining pattern. This is the first demonstration of a metabotropic P2Y receptor in the guinea pig organ of Corti.

scholarly journals An Analytical Mechanical Model of Corti in the Cochlea

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jiangtao Su ◽  
Wenjuan Yao ◽  
Zhengshan Zhao
Keyword(s):  
Mechanical Model ◽  
Basilar Membrane ◽  
Low Frequency ◽  
Organ Of Corti ◽  
Negative Influence ◽  
Outer Hair Cells ◽  
Tectorial Membrane ◽  
Response Patterns ◽  
Motion Patterns ◽  
Loss Of Hearing

The organ of Corti (OC) in the cochlea is a significant structure for feeling sound. The components of OC and the interaction of the part with the surroundings contribute to the fact that the passive tuning of the cochlear macrostructure is unclear. Based on the interaction between the basilar membrane (BM), tectorial membrane (TM), reticular lamina (RL), and various parts of OC, a mechanical model of the cochlea is established to study the motion patterns of each part under the action of a certain pressure. The variational principle is applied to the calculation of the analytical expression of the displacement of the BM. The results of the analytical solution differ little from the experimental value, and the variation trend is consistent, which presents the correctness of the model. The parameter sensitivity analysis is carried out for obtaining the interaction principle and the primary and secondary roles of each component in the process of the sense of sound. The results show that the absence of the TM and the decrease in the stiffness of the outer hair cells (OHCs) and OHC bundles will shift vibratory response patterns to lower frequencies, in which the lack of TM will result in the greatest reduction of CF. The absence of RL exerts a negative influence on the CF as well as the amplitude of BM and thereby loss of hearing. Therefore, both TM and RL are essential structures during the process of the sense of sound. At the same time, the resonance frequency at the base of the BM is concentrated on the high-frequency segment, while the apex of the BM is mainly in the low frequency. Different points of BM correspond to different CF, which demonstrates the frequency selectivity of the BM.

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