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Titolo:
The photopic negative response of the macaque electroretinogram: Reductionby experimental glaucoma
Autore:
Viswanathan, S; Frishman, LJ; Robson, JG; Harwerth, RS; Smith, EL;
Indirizzi:
Univ Houston, Coll Optometry, Houston, TX 77204 USA Univ Houston Houston TX USA 77204 , Coll Optometry, Houston, TX 77204 USA
Titolo Testata:
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
fascicolo: 6, volume: 40, anno: 1999,
pagine: 1124 - 1136
SICI:
0146-0404(199905)40:6<1124:TPNROT>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
SCOTOPIC THRESHOLD RESPONSE; GANGLION-CELL LOSS; B-WAVE; OPTIC-NERVE; GLIAL-CELLS; PATTERN ERG; CAT RETINA; MONKEY; COMPONENT; DAMAGE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
60
Recensione:
Indirizzi per estratti:
Indirizzo: Frishman, LJ Univ Houston, Coll Optometry, Houston, TX 77204 USA Univ Houston Houston TX USA 77204 try, Houston, TX 77204 USA
Citazione:
S. Viswanathan et al., "The photopic negative response of the macaque electroretinogram: Reductionby experimental glaucoma", INV OPHTH V, 40(6), 1999, pp. 1124-1136

Abstract

PURPOSE. TO investigate the photopic flash electroretinograms (ERGs) of macaque monkeys in which visual field defects developed as a consequence of experimental glaucoma. METHODS. Unilateral experimental glaucoma was induced in 10 monkeys by argon laser treatment of the trabecular meshwork. Visual field sensitivity wasassessed behaviorally by static perimetry. Photopic ERGs were recorded to brief- (less than or equal to 5 msec) and long-duration (200 msec) red ganzfeld hashes on a rod-suppressing blue-adapting background. Electroretinograms were recorded in four other monkeys, after intravitreal injection of tetrodotoxin (TTX; 3.8-8 mu M) to suppress action potentials of retinal ganglion and amacrine cells, and in six normal adult human subjects. RESULTS. Experimental glaucoma removed a cornea-negative response, the photopic-negative response (PhNR), from the ERG. The PhNR in control eyes was maximal approximately 60 msec after a brief flash, 100 msec after onset: and 115 msec after offset of the long-duration stimulus. The PhNR in experimental eyes was greatly reduced when the mean deviation of the visual field sensitivity was as little as -6 dB. As visual sensitivity declined further, the PhNR was reduced only slightly more. The a and b-waves were unchanged, even when sensitivity decreased by more than 16 dB. Tetrodotoxin also selectively reduced the PhNR. The PhNR was observed in normal human ERGs. CONCLUSIONS. The cornea-negative PhNR of the photopic ERG depends on spiking activity and is reduced in experimental glaucoma when visual sensitivitylosses are still mild. The PhNR most likely arises from retinal ganglion cells and their axons, but its slow timing raises the possibility that it could be mediated by glia. Regardless of the mechanism of its generation, thePhNR holds promise as an indicator of retinal function in early glaucomatous optic neuropathy.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/04/20 alle ore 08:35:16