Journal of Neurophysiology, Vol 60, Issue 4 1460-1480, Copyright © 1988 by APS

ARTICLES

Membrane currents of retinal bipolar cells in culture

E. M. Lasater
Department of Physiology, University of Utah School of Medicine, Salt Lake City 84108.

1. Retinal bipolar cells were isolated from white bass retinas and maintained in a cell culture preparation. Two morphological types of bipolar cells were observed in cell culture. These were labeled large- and small-bipolar cells based mainly on the size of their somata and primary dendrites. Two types of small-bipolar cells were observed. Isolated bass bipolar cells are very similar to those described in the intact retina. 2. Under current clamp, to depolarizing current injection, small-bipolar cells produced a spike followed by a plateau. Large-bipolar cells showed a slow depolarization to a plateau level. 3. Voltage-gated membrane currents were studied using whole-cell patch-clamp techniques. Channel blocking agents were used to define the ion channels found in the membranes of these cells. 4. The large-bipolar cells were found to possess an A-current, a calcium current, and a calcium-dependent potassium current. 5. Large bipolar cells also possessed an inward rectifier that did not correspond to any previously described. 6. The two types of small-bipolar cells were found to have very similar membrane properties to one another. They lacked a large A-current but possessed a slowly activating, outward rectifying potassium current. Similar to the large-bipolar cells, they showed a calcium current and a calcium-activated potassium current. 7. The inward rectifier of small-bipolar cells was characterized as an H-current. 8. The results suggest that the membrane currents of bipolar cells set a narrow operating range about which the cells function in the intact retina. In addition these currents help shape the responses of bipolar cells to light stimuli but do not confer ON or OFF properties.

This article has been cited by other articles:

				E. Margalit and W. B. Thoreson Inner retinal mechanisms engaged by retinal electrical stimulation. Invest. Ophthalmol. Vis. Sci., June 1, 2006; 47(6): 2606 - 2612. [Abstract] [Full Text] [PDF]

				Y.-P. Ma, J. Cui, H.-J. Hu, and Z.-H. Pan Mammalian Retinal Bipolar Cells Express Inwardly Rectifying K+ Currents (IKir) With a Different Distribution Than That of Ih J Neurophysiol, November 1, 2003; 90(5): 3479 - 3489. [Abstract] [Full Text] [PDF]

				B.-Q. Mao, P. R. MacLeish, and J. D. Victor Role of Hyperpolarization-Activated Currents for the Intrinsic Dynamics of Isolated Retinal Neurons Biophys. J., April 1, 2003; 84(4): 2756 - 2767. [Abstract] [Full Text] [PDF]

				J. Snellman and S. Nawy Regulation of the Retinal Bipolar Cell mGluR6 Pathway by Calcineurin J Neurophysiol, September 1, 2002; 88(3): 1088 - 1096. [Abstract] [Full Text] [PDF]

				Z.-H. Pan and H.-J. Hu Voltage-Dependent Na+ Currents in Mammalian Retinal Cone Bipolar Cells J Neurophysiol, November 1, 2000; 84(5): 2564 - 2571. [Abstract] [Full Text] [PDF]

				G. B. Awatramani and M. M. Slaughter Origin of Transient and Sustained Responses in Ganglion Cells of the Retina J. Neurosci., September 15, 2000; 20(18): 7087 - 7095. [Abstract] [Full Text] [PDF]

				Z.-H. Pan Differential Expression of High- and Two Types of Low-Voltage-Activated Calcium Currents in Rod and Cone Bipolar Cells of the Rat Retina J Neurophysiol, January 1, 2000; 83(1): 513 - 527. [Abstract] [Full Text] [PDF]