Glycine- and GABA-activated inhibitory currents on axon terminals of rabbit cone bipolar cells.
Glycine- and GABA-activated currents were examined in the axon terminals of 12 types of rabbit cone bipolar cells. In the superfused retinal slice, a cell was voltage clamped at 0 mV in the presence of cobalt; then glycine or GABA was puffed onto the axon terminal. Types CBa1, CBa2, and a few CBa1-2 cells demonstrated larger glycine-activated currents than GABA-activated ones. However, some OFF cells (CBa2(n), CBa1-2(n), CBa1(w)), most CBa1-2, and most ON cells (CBb3, CBb3-4, CBb3(n), and CBb4) displayed larger GABA-activated currents. The ON cell, CBb5, possessed only a GABA-activated current. The predominance of glycinergic currents in CBa1, CBa2, and a few CBa1-2 cells suggests a major input from the glycinergic AII amacrine cell and thus a key role for these cells in the rod bipolar pathway. Certain OFF cells (most CBa1-2) expressed larger GABA-activated currents. All types expressed both GABA(A) and GABAC currents about equally, although most OFF types (CBa1, CB a2(n), CBa1-2, and CBa2(n)) displayed a slightly greater GABA(A) component.
Department of Ophthalmology, University of Alabama at Birmingham, USA.
Chengwen
C
Zhou
Ramon F
RF
Dacheux
D000328:Adult; D016477:Artifacts; D003116:Color; D015350:Contrast Sensitivity / Q000502:physiology*; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D015233:Models, Statistical; D010775:Photic Stimulation; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology