Cytochemical evidence for redistribution of membrane pump calcium-ATPase and ecto-Ca-ATPase activity, and calcium influx in myelinated nerve fibres of the optic nerve after stretch injury

1995 ◽  
Vol 24 (12) ◽  
pp. 925-942 ◽  
Author(s):  
W. L. Maxwell ◽  
B. J. McCreath ◽  
D. I. Graham ◽  
T. A. Gennarelli
1974 ◽  
Vol 187 (1089) ◽  
pp. 421-447 ◽  

Potentials in the amphibian tectum, evoked by stimulation of the optic nerve, were recorded extracellularly. Four discrete potentials, referred to as the m 1 , m 2 , u 1 and u 2 waves, occur at different latencies after stimulation. We have shown that these waves represent summed post-synaptic potentials generated by synchronous activation of four different groups of optic nerve fibres. The m 1 and m 2 waves are generated by two classes of myelinated optic nerve fibres, previously characterized as ‘dimming’ and ‘event’ fibres. The maximum amplitude of the m 2 wave occurs just below, and of the m 2 wave just above, cell layer 8 of P. Ramón. The u 1 and u 2 waves are generated by ‘edge’ and ‘convexity’ fibres, respectively. The maximum amplitude of the u 1 wave occurs near the surface of the tectum, and of the u 2 wave some 100 μm below it. Postsynaptic cell bodies for all four classes of optic fibre are located in layer 8.


2009 ◽  
Vol 137 (3-4) ◽  
pp. 130-133
Author(s):  
Ivan Stefanovic ◽  
Ivan Marjanovic ◽  
Gordana Vlajkovic

Introduction. The ultrasound diagnostics of the optic nerve includes the analysis of the optic nerve disc (PNO) and measuring of its retrobulbar diameter. With B-scan, by Schraeder's method, it is possible to measure very precisely the optic nerve, the pial diameter, the normal values for the pial diameter being 2.8-4.1 mm. In glaucoma, the disease that is most frequently associated with higher intraocular pressure, there comes the destruction of nerve fibres, which can be visualized as the excavation of the optic nerve disc. Objective. In this paper, we were interested in finding whether in glaucoma, and in what phase of the disease, the optic nerve starts growing thinner. Aware of many forms of this very complex disease, we were interested in knowing if the visualization of excavation on the optic nerve disc is related to diminishing of the pial diameter of the retrobulbar nerve part. Methods. There were treated the patients who had already had the diagnosis of glaucoma and the visualized excavation of the optic disc of various dimensions. Echographically, there was measured the thickness of the retrobulbar part of the optic nerve and the finding compared in relation to the excavation of the optic disc. Results. In all eyes with glaucoma, a normal size of the retrobulbar part of the optic nerve was measured, ranging from 3.01 to 3.91 mm with the median of 3.36 mm. Also, by testing the correlation between the thickness of the optic nerve and the excavation of the PNO, by Pearson test, we found that there was no correlation between these two parameters (r=0.109; p>0.05). Conclusion. In the patients with glaucoma, the retrobulbar part of the optic nerve is not thinner (it has normal values), even not in the cases with a totally excavated optic disc. There is no connection between the size of the PNO excavation and the thickness of the retrobulbar part of the optic nerve.


1974 ◽  
Vol 60 (2) ◽  
pp. 383-396
Author(s):  
HOWARD L. GILLARY

1. The cornea-negative ERG of the eye of Strombus exhibited two distinct ‘on’ peaks, a steady state during sustained illumination, and small rhythmic oscillations following the cessation of stimulation. 2. In certain afferent optic nerve fibres, illumination evoked phasic and tonic ‘on’ responses; others, whose activity was inhibited by light, responded with repetitive ‘off’ bursts which tended to occur in phase with the rhythmic ERG oscillations. 3. Spectral sensitivity studies indicate the presence of a single visual pigment with a peak absorption of about 485 nm. 4. The effects on the response of temperature and stimulus intensity and frequency were also examined. 5. The results indicate photo-excitation and synaptic inhibition of the receptors, and excitatory coupling between them.


1967 ◽  
Vol 2 (3) ◽  
pp. 349-358
Author(s):  
R. M. EAKIN ◽  
JANE A. WESTFALL ◽  
M. J. DENNIS

The eye of a nudibranch, Hermissenda crassicornis, was studied by light and electron microscopy. Three kinds of cells were observed: large sensory cells, each bearing at one end an array of microvilli (rhabdomere) and at the other end an axon which leaves the eye by the optic nerve; large pigmented supporting cells; and small epithelial cells, mostly corneal. There are five sensory cells, and the same number of nerve fibres in the optic nerve. The receptor cells contain an abundance of small vesicles, 600-800 Å in diameter. The lens is a spheroidal mass of osmiophilic, finely granular material. A basal lamina and a capsule of connective tissue enclose the eye. In some animals the eye is ‘infected’ with very small bodies, 4-5 µ in diameter, thought to be symbionts.


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