JN Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 62: 469-480, 1989;
0022-3077/89 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ariel, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ariel, M.

Journal of Neurophysiology, Vol 62, Issue 2 469-480, Copyright © 1989 by APS

ARTICLES

Analysis of vertebrate eye movements following intravitreal drug injections. III. Spontaneous nystagmus is modulated by the GABAa receptor

M. Ariel
Department of Behavioral Neuroscience, University of Pittsburgh, PA 15260.

1. Turtle eye movements were recorded in response to horizontal motion of patterned stimuli and intravitreal injections of selective GABAergic drugs by using a contact lens search-coil technique. Similar to results from rabbit and cat, injection of picrotoxin into the turtle's eye results in a spontaneous horizontal nystagmus, with its slow-phase movement in a temporal-to-nasal direction with respect to the injected eye. In contrast, there were no prominent vertical eye movements in response to either horizontal optokinetic stimuli or drug injections. 2. Injections of bicuculline or bicuculline methyl iodide (BMI), which selectively block the GABAa receptor, had effects similar to those of picrotoxin. The GABAa agonist muscimol, on the other hand, blocked optokinetic nystagmus (OKN). Furthermore, combinations of these drugs demonstrated competitive interactions between the agonists and antagonists. 3. The threshold dose for the eye-movement effects of each drug was ascertained with the use of a radioactive calibration procedure. Tritiated inulin was injected into the vitreous. After 1 h, ocular components were assayed for radioactivity. Then, by the use of an estimate of vitreal/retinal dilution, the retinal concentrations of these threshold doses were calculated. The computed threshold retinal concentrations of the GABAa drugs were found to be in the low micromolar range. 4. These results are discussed in terms of the directionally sensitive (DS) processing which occurs in the retina, and the output of retinal DS cells to pathways involved in oculomotor control of retinal image stabilization. It is known that intravitreal application of picrotoxin makes DS retinal ganglion cells lose their selectivity for any one direction. Based on the effect of picrotoxin on OKN, it is argued that DS retinal cells provide a major input to oculomotor subsystems involved in the stabilization of gaze. Furthermore, these intravitreal drug effects on OKN are selective for GABAa drugs, suggesting that GABAa receptors play a major role in DS processing in the retina.


This article has been cited by other articles:


Home page
 J. Neurosci.Home page
K.-P. Hoffmann, N. Garipis, and C. Distler
Optokinetic Deficits in Albino Ferrets (Mustela putorius furo): A Behavioral and Electrophysiological Study
J. Neurosci., April 21, 2004; 24(16): 4061 - 4069.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
N. Kogo, D. M. Rubio, and M. Ariel
Direction Tuning of Individual Retinal Inputs to the Turtle Accessory Optic System
J. Neurosci., April 1, 1998; 18(7): 2673 - 2684.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online