scholarly journals Elucidating the Role of AII Amacrine Cells in Glutamatergic Retinal Waves

2015 ◽  
Vol 35 (4) ◽  
pp. 1675-1686 ◽  
Author(s):  
A. Firl ◽  
J.-B. Ke ◽  
L. Zhang ◽  
P. G. Fuerst ◽  
J. H. Singer ◽  
...  
2014 ◽  
Vol 127 (6) ◽  
pp. 1190-1202 ◽  
Author(s):  
A. Meyer ◽  
G. Hilgen ◽  
B. Dorgau ◽  
E. M. Sammler ◽  
R. Weiler ◽  
...  

2009 ◽  
Vol 101 (5) ◽  
pp. 2339-2347 ◽  
Author(s):  
Margaret Lin Veruki ◽  
Espen Hartveit

Gap junction channels constitute specialized intercellular contacts that can serve as electrical synapses. In the rod pathway of the retina, electrical synapses between AII amacrine cells express connexin 36 (Cx36) and electrical synapses between AII amacrines and on-cone bipolar cells express Cx36 on the amacrine side and Cx36 or Cx45 on the bipolar side. For physiological investigations of the properties and functions of these electrical synapses, it is highly desirable to have access to potent pharmacological blockers with selective and reversible action. Here we use dual whole cell voltage-clamp recordings of pairs of AII amacrine cells and pairs of AII amacrine and on-cone bipolar cells in rat retinal slices to directly measure the junctional conductance ( Gj) between electrically coupled cells and to study the effect of the drug meclofenamic acid (MFA) on Gj. Consistent with previous tracer coupling studies, we found that MFA reversibly blocked the electrical synapse currents in a concentration-dependent manner, with complete block at 100 μM. Whereas MFA evoked a detectable decrease in Gj within minutes of application, the time to complete block of Gj was considerably longer, typically 20–40 min. After washout, Gj recovered to 20–90% of the control level, but the time to maximum recovery was typically >1 h. These results suggest that MFA can be a useful drug to investigate the physiological functions of electrical synapses in the rod pathway, but that the slow kinetics of block and reversal might compromise interpretation of the results and that explicit monitoring of Gj is desirable.


2013 ◽  
Vol 14 (S1) ◽  
Author(s):  
Hermann Riecke ◽  
Hannah Choi ◽  
Mark S Cembrowski ◽  
William L Kath ◽  
Joshua H Singer

2018 ◽  
Vol 28 (17) ◽  
pp. 2739-2751.e3 ◽  
Author(s):  
Cole W. Graydon ◽  
Evan E. Lieberman ◽  
Nao Rho ◽  
Kevin L. Briggman ◽  
Joshua H. Singer ◽  
...  

2004 ◽  
Vol 315 (3) ◽  
pp. 407-412 ◽  
Author(s):  
Sung-Jin Park ◽  
Eun-Jin Lim ◽  
Su-Ja Oh ◽  
Jin-Woong Chung ◽  
Dennis W. Rickman ◽  
...  

2008 ◽  
Vol 100 (6) ◽  
pp. 3305-3322 ◽  
Author(s):  
Margaret Lin Veruki ◽  
Leif Oltedal ◽  
Espen Hartveit

AII amacrine cells form a network of electrically coupled interneurons in the mammalian retina and tracer coupling studies suggest that the junctional conductance ( Gj) can be modulated. However, the dynamic range of Gj and the functional consequences of varying Gj over the dynamic range are unknown. Here we use whole cell recordings from pairs of coupled AII amacrine cells in rat retinal slices to provide direct evidence for physiological modulation of Gj, appearing as a time-dependent increase from about 500 pS to a maximum of about 3,000 pS after 30–90 min of recording. The increase occurred in recordings with low- but not high-resistance pipettes, suggesting that it was related to intracellular washout and perturbation of a modulatory system. Computer simulations of a network of electrically coupled cells verified that our recordings were able to detect and quantify changes in Gj over a large range. Dynamic-clamp electrophysiology, with insertion of electrical synapses between AII amacrine cells, allowed us to finely and reversibly control Gj within the same range observed for physiologically coupled cells and to examine the quantitative relationship between Gj and steady-state coupling coefficient, synchronization of subthreshold membrane potential fluctuations, synchronization and transmission of action potentials, and low-pass filter characteristics. The range of Gj values over which signal transmission was modulated depended strongly on the specific functional parameter examined, with the largest range observed for action potential transmission and synchronization, suggesting that the full range of Gj values observed during spontaneous run-up of coupling could represent a physiologically relevant dynamic range.


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