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   Table of Contents      
ARTICLE
Year : 1969  |  Volume : 17  |  Issue : 5  |  Page : 201-207

Proteins of visual pathways having varied retinal receptors in altered conditions of visual stimuli


Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All-India Institute of Medical Sciences, New Delhi - 16, India

Date of Web Publication11-Jan-2008

Correspondence Address:
S Goswamy
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All-India Institute of Medical Sciences, New Delhi - 16
India
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Source of Support: None, Conflict of Interest: None


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How to cite this article:
Goswamy S, Agarwal L P, Pahuja S L. Proteins of visual pathways having varied retinal receptors in altered conditions of visual stimuli. Indian J Ophthalmol 1969;17:201-7

How to cite this URL:
Goswamy S, Agarwal L P, Pahuja S L. Proteins of visual pathways having varied retinal receptors in altered conditions of visual stimuli. Indian J Ophthalmol [serial online] 1969 [cited 2020 Jun 4];17:201-7. Available from: http://www.ijo.in/text.asp?1969/17/5/201/38541

Table 5

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Table 5

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Table 4

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Table 3

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Table 2

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Table 2

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Table 1

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Table 1

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After assessing the role of light in maturing visual pathways by electro­physiological (Goswamy, [3] ) and some biochemical parameters, (Goswamy and Mandel, [2] and Goswamy [4] ) we observed that the absence of visual stimuli since birth may bring about the functional and/or biochemical alterations in the functional matu­ration of visual pathways. In the last gathering of the XXVIII All-India Ophthalmological Conference (Go­swamy, 1968 a), we presented the data which was thought to contribute to­wards a better understanding of me­chanism of amblyopia in cases devoid of adequate visual stimuli during ma­turation of visual pathways.

In an effort to further substantiate our previous studies we have under­taken the investigation of protein levels in visual pathways having varied reti­nal receptors (Rod mainly, cone only, or mixed rod and cone retinae). The changes of proteins in these visual path­ways have been studied under altered conditions of visual stimuli which re­semble closely some of the causes of arnblyopia in human beings, e.g. cor­neal or lenticular opacities.


  Materials and Methods Top


The distribution of total proteins in different regions of visual pathways of normal adult animals having either rod (frog-R. Tigrina), or cone (domes­tic pigeon), or mixed rod and cone (al­bino rabbit) retinae has been deter­mined. The various areas of visual pathways taken for the study of protein levels in each animal are given in the different tables and figures be­low.

The corneal or lenticular opacifica­tion has been produced by trauma with a cataract knife under sterile and aseptic conditions as far as possible. Besides this the infection and inflam­mation was prevented by a regular lo­cal use of chloromycetin and atropine ophthalmic ointments. The pigeons were kept devoid of all visual stimuli in a completely dark room with a thick black paper firmly stuck over the eyes with sticking plaster. This in addition was secured by a black bandage spe­cially designed for the pigeons head.

The total proteins were determined by the method of Lowry, Rosebrough Farr and Randall, [8] as modified by Cowgill and Pardee. [1]


  Observations and Comments Top


[Table - 1] presents in a concise form the distribution of proteins in various regions of the visual pathways of rab­bit which has mixed rods and cones, pigeon which has cones only and frog which has rods mainly as reported in a previous contribution by us-Goswamy Agarwal and Pahuja. [7]

It can be seen that the total proteins in the corresponding visual pathways in the three groups are almost equal.

From [Table - 1], it is evident that the retina has the least amount of pro­teins, while the lower visual centres (that is, lateral geniculate body, supe­rior colliculus, or optic lobes) have the maximum. The protein content in the visual cortex (higher visual centre) is between these two extremes. Although the difference in protein contents of retina, lower visual centres, and higher visual centres is small, it is statistically significant (p. < 0.01). However, there is no statistical difference in the pro­tein contents of visual cortex as com­pared to frontal or olfactory lobes in the three animals.

From this one may infer that no mat­ter what is the type of visual system, habitat, or the visual requirements, de­manding either predominantly day or night vision in its own special environ­ments, the proteins per unit of the in­dividual component of visual system of the three animals studied, is more or less constant and identical, under normal circumstances of the different visual behaviours.

With this base for the normal pro­tein levels in visual pathways, we have started to observe the changes in pro­tein contents of visual system after visual deprivation either by total ex­clusion of visual stimuli (patching of eyes in dark), or by a more natural process of corneal or lenticular opacifi­cation which provides only a partial blockage to the light stimulus. The initial results of this study are pre­sented here under.

In [Table - 2] and [Figure - 1], we find that the presence of partial or total trau­matic cataract in frog's eyes brings about the lowering of proteins in the optic lobes (the main visual centre in frog) by 1.6 times as compared to nor­mal. This difference is highly signi­ficant statistically (p. < 0.001). How­ever, this traumatic cataract for 10 days in adult frog does not alter the protein contents in the retina or olfactory lobe of the same animals.

Similarly from [Table - 3] and [Figure - 2], we observe that traumatic cataract in adult rabbits lowers the protein levels in a significant manner (p < 0.01) in the lateral geniculate body and occi­pital (visual) cortex, that is, in the lower and higher visual centres in rab­bit respectively. Again there is no statistically significant change in pro­tein contents of other parts of visual system studied in these animals with traumatic cataract for four weeks.

Looking at [Table - 4] and [Figure - 2], we note that traumatic corneal opacifica­tion for two months or more in adult rabbit brings about some lowering of proteins in the visual cortex, lateral geniculate body, and even retina, but the p-value is less significant as com­pared to that in traumatic cataract se­ries. This is possibly due to a less thick and mainly central corneal opacities produced in these animals. To clarify this doubt we are running another se­ries of experiments with total and deep corneal opacities.

This data from [Table - 2],[Table - 3],[Table - 4] shows that visual deprivation by trau­matic cataract or corneal opacification mainly lowers the protein contents of the visual centres (higher and lower), and in a less significant manner of the retina also. This means the cellular regions of the visual system are the site of alterations in proteins by a lack of visual stimuli. This compares very favourably with our previous results for the developing visual pathways of rabbits born and brought up in total darkness (Goswamy and Mandel [2] ). In this study we observed a reduc­tion in proteins per cell in retina, lateral geniculate body and visual cor­tex. Also the levels of RNA and DNA at 15 or 21 days age were more close to those between birth and 8 days, that is, before the first opening of the eyes. We have also noted a retardation in the evolution of distribution and syn­thesis of proteins, nucleic acids, and even the functional maturation of vi­sual pathways electrophysiologically in these rabbits reared in complete dark­ness. This electrophysiological work indicated to us that retardation in ma­turation of visual evoked responses in absence of light is mainly situated at the level of visual cortex (Goswamy, Bonaventure and Karli [5] ). Our work is further supported by the observations of Maraini, Carta, Franguelli, and Santori, [9] ) who have reported that monocular light-deprivation in new born rats, shortly after the first open­ing of eyes, produces a significant de­crease of [3] H-leucine incorporation in the lateral geniculate nucleus, reflect­ing thereby a decrease in protein syn­thesis. They, however, did not find any modification of the amino acid uptake in the different cellular layers of the retina and visual cortex. To add to this, Talwar, Chopra, Goel and D'Monte [10] have also noted significantly lower content of proteins in the occi­pital cortex of 2-weeks old rab­bits, who were blinded after birth by enucleation of the eyes at birth. They inferred from this that protein content of the occipital cortex is possibly de­pendent on the light stimulus. They also found that animals kept in dark had less incorporation of radioactive amino-acid ( 14 C-valine) in occipital cortex proteins, as compared to ani­mals exposed to light stimulus.

The total proteins in visual pathways of pigeons devoid of all visual stimuli for 48 hours are only slightly lowered, though significant statistically, in the optic lobes [Table - 5] and [Figure - 3]. The absence of modifications in protein dis­tribution in visual pathways may only be due to a short duration of 48 hours for the visual deprivation. Further studies with longer duration of visual deprivation are underway. This, in any case, also points to a decrease in proteins at the visual centres in stimu­lus deprivation.

Thus, one may deduce from these observations that no matter, what type of visual system is employed and what mode of visual deprivation is instituted, the lack of visual stimuli diminishes the contents and biosynthesis of pro­teins in the cellular regions of visual system, and this is more marked in the higher or lower visual centres but less so in the retina. The latter may be either due to a comparatively shorter duration of visual deprivation, or that adult retina does not show the gross alterations in proteins very easily. This is being further investigated. However this study lends some more information for the better understanding of the ra­ther eluding mechanism of amblyopia ex anopsia.


  Acknowledgements Top


The dexterous technical help to this work was given by Mr. Satish Kumar. This study is supported by a research grant from Indian council of medical research.

 
  References Top

1.
Cowgill R. W. and Pardee A. B. (1957) -Experiments in biological research techniques, P. 176, pub].. John Wiley, New York.  Back to cited text no. 1
    
2.
Goswamy S., Mandel P. and Karli, P.: (1966)-International symposium of ophthalmic biochemistry, held at Tut­zing (W. Germany)-p. 514. Krager Ba­set. August, 1966.  Back to cited text no. 2
    
3.
Goswamy S. (1968 b)-Paper presented at the annual session of Indian Aca­demy of Medical Sciences. held at New Delhi in December, 1968.  Back to cited text no. 3
    
4.
Goswamy S. (1967)-Thesis presented for the award of 'docteur es-sciences' to the University of Strasbourg (France) - in May, 1967.  Back to cited text no. 4
    
5.
Goswamy S., Bonaventure N. and Karli P. C. R. Soc. Biol. (France)­161, 921 (1967).  Back to cited text no. 5
    
6.
Goswamy S. (1968 a)-Paper presented at the XXVIII All-India Ophthalmolo­gical conference, held at Ahmedabad in Jan. 1968.  Back to cited text no. 6
    
7.
Goswamy S., Agarwal L. P., and Pa­huia S. L. (1969)-Oriental Arch. of Ophthal. 7, 93, (1969).  Back to cited text no. 7
    
8.
Lowry O. H., Rosebrough N. J., Farr A. L., and Randall R. J. (1951)-J. Biol. Chem.-193, 265.  Back to cited text no. 8
    
9.
Maraini G., Carta F., Franguelli R. and Santori M.-Exptl. Eye Res.-6, 299 (1967).  Back to cited text no. 9
    
10.
Talwar G. P., Chopra S. P., Goel B. K. and D'Monte B.-J. Neurochem.-­13, 109 (1966).  Back to cited text no. 10
    


    Figures

  [Figure - 1], [Figure - 2], [Figure - 3]
 
 
    Tables

  [Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5]



 

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