|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Received November 8, 2002
Accepted after revision December 23, 2002
1 Department of Ophthalmology, UCSF School of Medicine, Box 0730, Room K-140, 10 Kirkham Street, San Francisco, CA 94143-0730, USA
2 Cell Signalling Laboratory, Wales Heart Research Institute, University of Wales College of Medicine, Cardiff CF14 4XN, UK
3 Departments of Ophthalmology and Physiology, UCSF School of Medicine, San Francisco, CA 94143, USA
* To whom correspondence should be addressed. E-mail: krizaj{at}phy.ucsf.edu.
Despite the prominent role played by intracellular Ca2+ stores in the regulation of neuronal Ca2+ homeostasis and in invertebrate photoreception, little is known about their contribution to the control of free Ca2+ concentration ([Ca2+]i) in the inner segments of vertebrate photoreceptors. Previously, caffeine-sensitive intracellular Ca2+ stores were shown to play a role in regulating glutamate release from photoreceptors. To understand the properties of these intracellular stores better we used pharmacological approaches that alter the dynamics of storage and release of Ca2+ from intracellular compartments. Caffeine evoked readily discernible changes in [Ca2+]i in the inner segments of rods, but not cones. Caffeine-evoked Ca2+ responses in cone inner segments were unmasked in the presence of inhibitors of the plasma membrane Ca2+ ATPases (PMCAs) and mitochondrial Ca2+ sequestration. Caffeine-evoked responses were blocked by ryanodine, a selective blocker of Ca2+ release and by cyclopiazonic acid, a blocker of Ca2+ sequestration into the endoplasmic reticulum. These two inhibitors also substantially reduced the amplitude of depolarization-evoked [Ca2+]i increases, providing evidence for Ca2+-induced Ca2+ release (CICR) in rods and cones. The magnitude and kinetics of caffeine-evoked Ca2+ elevation depended on the basal [Ca2+]i, PMCA activity and on mitochondrial function. These results reveal an intimate interaction between the endoplasmic reticulum, voltage-gated Ca2+ channels, PMCAs and mitochondrial Ca2+ stores in photoreceptor inner segments, and suggest a role for CICR in the regulation of synaptic transmission.
This article has been cited by other articles:
![]() |
T. Szikra, K. Cusato, W. B. Thoreson, P. Barabas, T. M. Bartoletti, and D. Krizaj Depletion of calcium stores regulates calcium influx and signal transmission in rod photoreceptors J. Physiol., October 15, 2008; 586(20): 4859 - 4875. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Sheng, S.-Y. Choi, A. Dharia, J. Li, P. Sterling, and R. H. Kramer Synaptic Ca2+ in Darkness Is Lower in Rods than Cones, Causing Slower Tonic Release of Vesicles J. Neurosci., May 9, 2007; 27(19): 5033 - 5042. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Yang, B. Pawlyk, X.-H. Wen, M. Adamian, M. Soloviev, N. Michaud, Y. Zhao, M. A. Sandberg, C. L. Makino, and T. Li Mpp4 is required for proper localization of plasma membrane calcium ATPases and maintenance of calcium homeostasis at the rod photoreceptor synaptic terminals Hum. Mol. Genet., May 1, 2007; 16(9): 1017 - 1029. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. P. Jensen, A. G. Filoteo, T. Knopfel, and R. M. Empson Presynaptic plasma membrane Ca2+ ATPase isoform 2a regulates excitatory synaptic transmission in rat hippocampal CA3 J. Physiol., February 15, 2007; 579(1): 85 - 99. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Cristofanilli and A. Akopian Calcium channel and glutamate receptor activities regulate actin organization in salamander retinal neurons J. Physiol., September 1, 2006; 575(2): 543 - 554. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Duncan, H. Yang, T. Doan, R. S. Silverstein, G. J. Murphy, G. Nune, X. Liu, D. Copenhagen, B. L. Tempel, F. Rieke, et al. Scotopic visual signaling in the mouse retina is modulated by high-affinity plasma membrane calcium extrusion. J. Neurosci., July 5, 2006; 26(27): 7201 - 7211. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Zissimopoulos, D. J. West, A. J. Williams, and F. A. Lai Ryanodine receptor interaction with the SNARE-associated protein snapin J. Cell Sci., June 1, 2006; 119(11): 2386 - 2397. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Suryanarayanan and M. M. Slaughter Synaptic Transmission Mediated by Internal Calcium Stores in Rod Photoreceptors J. Neurosci., February 8, 2006; 26(6): 1759 - 1766. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. C. Steele Jr., X. Chen, P. M. Iuvone, and P. R. MacLeish Imaging of Ca2+ Dynamics Within the Presynaptic Terminals of Salamander Rod Photoreceptors J Neurophysiol, December 1, 2005; 94(6): 4544 - 4553. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Rabl, L. Cadetti, and W. B. Thoreson Kinetics of Exocytosis Is Faster in Cones Than in Rods J. Neurosci., May 4, 2005; 25(18): 4633 - 4640. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Zhang, A. Beuve, and E. Townes-Anderson The Nitric Oxide-cGMP Signaling Pathway Differentially Regulates Presynaptic Structural Plasticity in Cone and Rod Cells J. Neurosci., March 9, 2005; 25(10): 2761 - 2770. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Verkhratsky Physiology and Pathophysiology of the Calcium Store in the Endoplasmic Reticulum of Neurons Physiol Rev, January 1, 2005; 85(1): 201 - 279. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Conti, Y. P. Tan, and I. Llano Action Potential-Evoked and Ryanodine-Sensitive Spontaneous Ca2+ Transients at the Presynaptic Terminal of a Developing CNS Inhibitory Synapse J. Neurosci., August 4, 2004; 24(31): 6946 - 6957. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. E. Kourennyi, X.-d. Liu, J. Hart, F. Mahmud, W. H. Baldridge, and S. Barnes Reciprocal Modulation of Calcium Dynamics at Rod and Cone Photoreceptor Synapses by Nitric Oxide J Neurophysiol, July 1, 2004; 92(1): 477 - 483. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. B. Thoreson, E. J. Bryson, and K. Rabl Reciprocal Interactions Between Calcium and Chloride in Rod Photoreceptors J Neurophysiol, September 1, 2003; 90(3): 1747 - 1753. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Kreft, D. Krizaj, S. Grilc, and R. Zorec Properties of Exocytotic Response in Vertebrate Photoreceptors J Neurophysiol, July 1, 2003; 90(1): 218 - 225. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |