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| 4. |
- Aschan, Gunnar, et al.
(författare)
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Xylene exposure. Electronystagmografic and gaschromatografic studies in rabbit
- 1977
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Ingår i: Acta Oto-Laryngologica. - : Informa Healthcare. - 0001-6489 .- 1651-2251. ; 84:1-6, s. 370-376
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Tidskriftsartikel (refereegranskat)abstract
- Complaints of vertigo from people who are exposed to industrial solvents have focused interest on their toxic effect on the nervous system. In order to evaluate the influence of an organic solvent, xylene, on the mammalian vestibular system, a series of rabbit experiments were performed. To achieve a constant concentration, the xylene was infused as a lipid emulsion. Blood concentrations were estimated by gas chromatography. Elec-tronystagmography in darkness revealed that at blood xylene concentrations of 30 ppm all rabbits had a positional nystagmus. The beat direction was the opposite of positional alcohol nystagmus. Another difference between the alcohol and the xylene reaction was that rotatory nystagmus responses were exaggerated. The relations between the present findings and the reactions and blood concentrations in people exposed to industrial solvents are discussed.
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| 5. |
- Larsby, Birgitta, et al.
(författare)
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Disturbances of the vestibular system by toxic agents
- 1976
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Ingår i: 15. Scandinavian Congress of Physiology and Pharmacology, Århus 1976. - : Fysiologisk Institut, Aarhus Universitet. ; , s. 157-157
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Larsby, Birgitta, et al.
(författare)
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Exposure of rabbits to methylchloroform. Vestibulardisturbances correlated to blood and cerebrospinal fluid levels
- 1978
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Ingår i: International Archives of Occupational and Environmental Health. - : Springer. - 0340-0131 .- 1432-1246. ; 41:1, s. 7-15
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Tidskriftsartikel (refereegranskat)abstract
- A previously described experimental model for studying the effects on the central nervous system of rabbits, specifically the vestibular apparatus, has been applied to methylchloroform. To achieve a steady concentration the solvent was infused as a lipid emulsion. The blood and cerebrospinal fluid kinetics have been studied. The arterial blood level seems to be closely correlated to the concentration in the central nervous tissue. Vestibular function has been studied by recording the involuntary eye movements — nystagmus — which are elicited via central vestibulo-oculomotor connections. At blood levels of methylchloroform above 75 ppm a so called “positional nystagmus”, indicated vestibular disturbances, is demonstrated. The relationship between the present findings in rabbits and the reaction and blood concentrations in people exposed to industrial solvents, are discussed.
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| 7. |
- Larsby, Birgitta, et al.
(författare)
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Exposure of rabbits to styrene. Electronystagmographic findings correlated to the styrene level in blood and cerebrospinal fluid
- 1978
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Ingår i: Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 4:1, s. 60-65
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Tidskriftsartikel (refereegranskat)abstract
- Objective methods for critically evaluating the toxic effect of industrial solvents are highly desirable. As many of these solvents are suspected to cause vertigo, an animal experimental model was set up for studying the effects of solvents on the vestibular systems. The vestibular function was studied by registration of involuntary eye movements--nystagmus--which are elicited via central vestibulo-oculomotor connections. During exposure to styrene a so-called positional nystagmus was demonstrated that indicated vestibular disturbances. Nystagmus is normally elicited by rotatory acceleration. During exposure to styrene the direction of this rotatory nystagmus was reversed. The incidence of the positional nystagmus correlated well with the blood level of the solvent, measured by gas chromatography. Kinetic studies also demonstrated a rapid equilibration between the level of the solvent in arterial blood and cerebrospinal fluid, and therefore suggested that estimation of the arterial level reliably indicates the level in the central nervous system.
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| 10. |
- Liedgren, Christer, et al.
(författare)
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Projection of thalamic neurons to cat primary vestibular cortical fields studied by means of retrograde axonal transport of horseradish peroxidase
- 1976
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Ingår i: Experimental Brain Research. - : Springer. - 0014-4819 .- 1432-1106. ; 24:3, s. 237-243
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Tidskriftsartikel (refereegranskat)abstract
- The two vestibular cortical projection areas in the anterior suprasylvian sulcus and post-cruciate dimple regions were defined by evoked potential technique in anaesthetized cats. The thalamic location of neurons with axon terminals in these fields was determined using the method of retrograde axonal transport of horseradish peroxidase. The ascending vestibular pathway appeared to be separated also at the thalamic level, where cells in the ventro-posterolateral nucleus were found to project to the post cruciate dimple and cells in the posterior nuclear group to the anterior suprasylvian vestibular cortical fields.
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| 11. |
- Rubin, Allan, et al.
(författare)
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Limb input to the cat vestibular nuclei
- 1979
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Ingår i: Acta Oto-Laryngologica. - : Informa Healthcare. - 0001-6489 .- 1651-2251. ; 87:1-2, s. 113-122
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Tidskriftsartikel (refereegranskat)abstract
- The input from fore- and hindlimbs to the vestibular nuclear complex (VNC) was investigated in awake cats. Electrical stimulus was given to the sciatic, radial and vestibular nerves bilaterally and single unit responses were recorded in the VNC with extracellular technique. The position of the microelectrode was histologically confirmed. All four major vestibular nuclei received fore- as well as hindlimb input. Forty per cent of the neurons with limb input also received vestibular afferents. No major distinguishing features appeared between the different nuclei with regard to response characteristics. Certain differences in laterality of response, quantitative fore-hindlimb ratio and somatosensory-labyrinthine convergence were observed however. Response latencies to sciatic and radial nerve stimuli always exceeded a 3 msec and were grouped around 8 and 16 msec. A third population of vestibular neurons had latencies over 20 msec. Both excitatory and inhibitory responses were recorded, with the latter not always following an activation. The findings illustrate the complex nature of the ascending pathway to the VNC and the integrative properties of this complex.
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| 13. |
- Tham, Richard, et al.
(författare)
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The influence of trichlorethylene and related drugs on the vestibular system
- 1979
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Ingår i: Acta Pharmacologica et Toxicologica. - : Wiley. - 0001-6683. ; 44:5, s. 336-342
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Tidskriftsartikel (refereegranskat)abstract
- A previously described experimental model for studying the effect of industrial solvents on the vestibular system of rabbits has been applied to trichloroethylene. Estimation of trichloroethylene and its metabolites in blood and cerebrospinal fluid was performed by gas chromatography. Vestibular function was studied by recording nystagmus, induced by positional changes or accelerated rotation. At blood levels of trichloroethylene above 30 p.p.m. “positional nystagmus” develops. Two metabolites of trichloroethylene, chloral hydrate and trichloro-ethanol, which are known as central nervous system (CNS) depressants, did not induce this abnormal nystagmus. However, α-chloralose, a derivative of chloral hydrate, induced positional nystagmus and also a markedly exaggerated nystagmus developed during rotatory acceleration. It is suggested that solvents like trichloroethylene elicit vestibular disturbances by stimulation of central subcortical vestibulo-oculomotor connections. The stimulation may be caused by a blockage of inhibitory systems.
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| 16. |
- Ödkvist, Lars, et al.
(författare)
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On the mechanisms of vestibular disturbancies caused by industrial solvents
- 1979
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Ingår i: Advances in Oto-Rhino-Laryngology. - : S. Karger. - 0065-3071 .- 1662-2847. ; 25, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- The industrial solvents xylene, styrene, trichloroethylene and methylchloroform administered to rabbits caused a positional nystagmus and disturbances in the nystagmus response to rotatory acceleration. The positional nystagmus had a beat direction the opposite to positional alcohol nystagmus, which was in similar experiments elicited by methanol, ethanol and propanol. The three alcohols needed a ten times higher blood concentration to cause a nystagmus than the solvents did.
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| 18. |
- Ödkvist, Lars, et al.
(författare)
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Projection of the vestibular nerve to the SI arm field in the cerebral cortex of the cat
- 1975
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 79:1-2, s. 88-95
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Tidskriftsartikel (refereegranskat)abstract
- Evoked cortical focal potentials from electrical vestibular nerve stimulation were recorded in the Pcd-area in cats anaesthetized with Chloralose or Nembutal. For comparison, additional cortical projections were located for n. rad. superficialis and group Ia muscle afferents from n. rad. prof., n. fibularis prof., n. femuralis ramus muscularis and the motor nerve to the trapezoid muscle. Surface positive potentials, which reversed to negativity in middle cortical layers, were for vestibular nerve stimulation recorded in the S I forelimb field in a small area close to Pcd in the posterior medial part of the deep radial nerve projection field. The location of this field is compared with the vestibulo-cortical projections described earlier for rodents, squirrel monkey, and rhesus monkey. The histology shows that the field was within the cytoarchitectonic 3a area.
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| 19. |
- Ödkvist, Lars, et al.
(författare)
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Vestibular and somatosensory inflow to the vestibular projection area in the post cruciate dimple region of the gat cerebral cortex
- 1975
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Ingår i: Experimental Brain Research. - : Springer. - 0014-4819 .- 1432-1106. ; 22:2, s. 185-196
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Tidskriftsartikel (refereegranskat)abstract
- In anesthetized cats 251 cells within the cortical vestibular projection area, adjacent to the post-cruciate dimple, were analyzed as to their input characteristics employing extracellular recording techniques. The post cruciate dimple vestibular field, which is located in area 3a, has a high degree of convergence between vestibular and peripheral somatosensory input. The latter is not restricted to muscle afferents but includes cutaneous modalities. The functional significance of this vestibular cortical projection field is discussed.
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