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Affiliation(s)
- Harris Ripps
- Department of OphthalmologyVisual ScienceAnatomyCell BiologyPhysiologyBiophysicsUniversity of Illinois College of MedicineChicago Illinois USA
- The Marine Biological LaboratoryWoods HoleMassachusetts USA
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Abstract
When reflected from a surface, light can provide a representation of the spatial environment, whilst gross changes in environment light can signal the time of day. The differing sensory demands of using light to detect environmental space and time appear to have provided the selection pressures for the evolution of different photoreceptor systems in the vertebrates, and probably all animals. This point has been well recognised in the non-mammals, which possess multiple opsin/vitamin A-based photoreceptor populations in a variety of sites distributed both within and outside the CNS. By contrast, eye loss in mammals abolishes all responses to light, and as a result, all photoreception was attributed to the rods and cones of the retina. However, studies over the past decade have provided overwhelming evidence that the mammalian eye contains a novel photoreceptor system that does not depend upon the input from the rods and cones. Mice with eyes but lacking rod and cone photoreceptors can still detect light to regulate their circadian rhythms, suppress pineal melatonin, modify locomotor activity, and modulate pupil size. Furthermore, action spectra for some of these responses in rodents and humans have characterised at least one novel opsin/vitamin A-based photopigment, and molecular studies have identified a number of candidate genes for this photopigment. Parallel studies in fish showing that VA opsin photopigment is expressed within sub-sets of inner retina neurones, demonstrates that mammals are not alone in having inner retinal photoreceptors. It therefore seems likely that inner retinal photoreception will be a feature of all vertebrates. Current studies are directed towards an understanding of their mechanisms, determining the extent to which they contribute to physiology and behaviour in general, and establishing how they may interact with other photoreceptors, including the rods and cones. Progress on each of these topics is moving very rapidly. As a result, we hope this review will serve as an introduction to the cascade of papers that will emerge on these topics in the next few years. We also hope to convince the more casual reader that there is much more to vertebrate photoreceptors than the study of retinal rods and cones.
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Affiliation(s)
- Russell G Foster
- Department of Integrative and Molecular Neuroscience, Faculty of Medicine, Imperial College of Science, Engineering and Medicine, Charing Cross Hospital, Fulham Palace Road, W6 8RF, London, UK.
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3
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Johnston JP, Aparicio JG, Applebury ML. Purification and autophosphorylation of retinal guanylate cyclase. Methods Enzymol 2000; 315:673-89. [PMID: 10736733 DOI: 10.1016/s0076-6879(00)15874-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- J P Johnston
- Howe Laboratory, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston 02114, USA
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Schmid HA, Riedel W, Simon E. Role of nitric oxide in temperature regulation. PROGRESS IN BRAIN RESEARCH 1998; 115:87-110. [PMID: 9632931 DOI: 10.1016/s0079-6123(08)62031-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- H A Schmid
- Max-Planck-Institute for Physiological and Clinical Research, William G. Kerckhoff-Institute, Bad Nauheim, Germany.
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5
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Gordon SE, Varnum MD, Zagotta WN. Direct interaction between amino- and carboxyl-terminal domains of cyclic nucleotide-gated channels. Neuron 1997; 19:431-41. [PMID: 9292731 DOI: 10.1016/s0896-6273(00)80951-4] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have examined domain interactions in the rod cyclic nucleotide-gated ion channel using both physiological and biochemical interaction assays. We have found an interaction between two regions of the channel distant in primary structure, the amino-terminal region and the carboxyl-terminal region containing the cyclic nucleotide-binding (CNB) domain. The interaction in functional channels was detected by the formation of a disulfide bond between cysteine residues at position 35 in the amino-terminal region and 481 in the carboxyl-terminal region. The disulfide bond resulted in channel potentiation, which was due, in part, to an increase in availability of C481 to modification when the channels were open. This state dependence is likely to underlie previously reported potentiation of cyclic nucleotide-gated channels by sulfhydryl-reactive compounds. Polypeptides derived from the amino-terminal and carboxyl-terminal regions were shown to interact, even under conditions which precluded disulfide bond formation. These data argue for a previously unknown, direct interaction between disparate regions of channel sequence.
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Affiliation(s)
- S E Gordon
- Department of Physiology and Biophysics, Howard Hughes Medical Institute, University of Washington, Seattle 98195, USA
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6
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Savini F, Berardi S, Tatone D, Spoto G. Phosphodiesterase in human colon carcinoma cell line CaCo-2 in culture. Life Sci 1995; 56:PL421-5. [PMID: 7746090 DOI: 10.1016/0024-3205(95)00169-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In a series of in vitro experiments we characterised the relationship between DNA distribution in the G1, S and G2/M phases of cell cycle and PDE and GST activity in CaCo-2 cells. The DNA distribution in CaCo-2 cells, was assessed by flow cytometry, with fluorescent dyes at different time points of culture. The exponential increase in cell number continued until day 10 when there was cell saturation. The effect of medium replacement on PDE activity was assayed in the first 10 h after medium replacement. The 6th hour is the time at which PDE activity was found to be highest. We have assayed the PDE enzyme with cGMP and cAMP as substrates. Only cAMP was consumed from this enzyme. We found a very close correlation between the DNA distribution in the various phases of the cell cycle and the PDE activity. PDE activity was very high during the active replication phase, whereas GST activity was high after confluency.
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Affiliation(s)
- F Savini
- Chair of Clinical Pathology, University G. D'Annunzio, Chieti, Italy
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Activation of the cystic fibrosis transmembrane conductance regulator by cGMP in the human colonic cancer cell line, Caco-2. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42310-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Kolesnikov SS, Kosolapov AV. Cyclic nucleotide-activated channels in carp olfactory receptor cells. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1150:63-72. [PMID: 8334139 DOI: 10.1016/0005-2736(93)90122-g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
When applied from the cytoplasmic side, cyclic 3',5'-adenosine and guanosine monophosphates reversibly increased the ion permeability of inside-out patches of carp olfactory neuron plasma membrane. The cAMP (cGMP)-induced permeability via cAMP (cGMP) concentration was fitted by Hill's equation with the exponents of 1.07 +/- 0.15 (1.12 +/- 0.05) and EC50 = 1.3 +/- 0.6 microM (0.9 +/- 0.3 microM). Substitution of NaCl in the bathing solution by chlorides of other alkali metals resulted in a slight shift of reversal potential of the cyclic nucleotide-dependent (CN) current, which indicates a weak selectivity of the channels. Permeability coefficients calculated by Goldman-Hodgkin-Katz's equation corresponded to the following relation: PNa/PK/PLi/PRb/PCs = 1:0.98:0.94:0.70:0.61. Ca2+ and Mg2+ in physiological concentrations blocked the channels activated by cyclic nucleotides (CN-channels). In the absence of divalent cations the conductance of single CN-channels was equal to 51 +/- 9 pS in 100 mM NaCl solution. Channel density did not exceed 1 micron-2. The maximal open state probability of the channel (Po) tended towards 1.0 at a high concentration of cAMP or cGMP. Dichlorobenzamil decreased Po without changing the single CN-channel' conductance. CN-channels exhibited burst activity. Mean open and closed times as well as the burst duration depended on agonist concentration. A kinetic model with four states (an inactivated, a closed and two open ones) is suggested to explain the regularities of CN-channel gating and dose-response relations.
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Affiliation(s)
- S S Kolesnikov
- Institute of Cell biophysics, Russian Academy of Sciences, Pushchino (Russian Federation)
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9
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Fabczak H, Tao N, Fabczak S, Song PS. Photosensory transduction in ciliates. IV. Modulation of the photomovement response of Blepharisma japonicum by cGMP. Photochem Photobiol 1993; 57:889-92. [PMID: 7687783 DOI: 10.1111/j.1751-1097.1993.tb09230.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effect of various modulators of cytoplasmic guanosine 3',5'-cyclic monophosphate (cGMP) level on the step-up photophobic responses in Blepharisma japonicum has been investigated to clarify the possible role of cGMP in the mechanism of photosensory signal transduction. Membrane-permeable analogs of cGMP, 8-bromo-guanosine 3',5'-cyclic monophosphate or dibutyryl cGMP, caused a marked dose-dependent prolongation of the latency for the photophobic response, resulting in inhibition of the photophobic response in Blepharisma japonicum. A similar effect was observed when cells were treated with 3'-isobutylmethylxanthine (IBMX), a phosphodiesterase inhibitor, and pertussis toxin, a G-protein activity modulator. The G-protein activator, fluoroaluminate, and 6-anilino-5,8-quinolinedione (LY 83583), an agent which effectively lowers the cytoplasmic cGMP level, significantly enhanced the photoresponsiveness of these ciliates to visible light stimuli. These results suggest that cellular cGMP serves as a signal modulator in the photophobic response of Blepharisma japonicum.
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Affiliation(s)
- H Fabczak
- Department of Cell Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw
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Fabczak H, Park PB, Fabczak S, Song PS. Photosensory transduction in ciliates. II. Possible role of G-protein and cGMP in Stentor coeruleus. Photochem Photobiol 1993; 57:702-6. [PMID: 8389485 DOI: 10.1111/j.1751-1097.1993.tb02941.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The heterotrichous ciliate, Stentor coeruleus, exhibits a well-defined photophobic response to a sudden increase in the intensity of visible light. The phobic reactions usually appear with a latency period (i.e. a time delay between the onset of the stimulus and the stop response). This latency of phobic response was significantly increased when the cells were incubated with 8-bromo-guanosine 3',5'-cyclic monophosphate. In the presence of this nucleotide, a reduction of cell responsiveness (i.e. the number of photophobically responding cells) was also observed. Similar effects were observed when cells were treated with pertussis toxin, a G-protein activity modulator, and 3'-isobutyl-methylxanthine, an inhibitor of guanosine 3',5'-cyclic monophosphate (cGMP) phosphodiesterase. The G-protein activator fluoroaluminate and 6-anilino-5,8-quinolinedione (LY 83583) (an effective agent for lowering cellular cGMP levels) showed opposite effects on the cell photophobic response. These results indirectly suggest that the level of cytoplasmic cGMP, possibly modulated by a G-protein-coupled cGMP phosphodiesterase, plays a phototransducing role in Stentor. In addition, using an antiserum raised against bovine transducin, a cross-reacting protein with an apparent molecular mass of 39 kDa was detected on immunoblots. The alpha-subunit of a Stentor G-protein has also been partially cloned and sequenced. However, the possible coupling between the G-protein and the putative phosphodiesterase remains to be established.
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Affiliation(s)
- H Fabczak
- Department of Cell Biology, Polish Academy of Sciences, Warsaw
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Kleene SJ. The cyclic nucleotide-activated conductance in olfactory cilia: effects of cytoplasmic Mg2+ and Ca2+. J Membr Biol 1993; 131:237-43. [PMID: 7684085 DOI: 10.1007/bf02260112] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Olfactory receptor neurons depolarize in response to odorants. This depolarization is mediated by an increase in intracellular cyclic AMP, which directly gates channels in the membranes of the neuronal cilia. Previous evidence suggests that a Ca2+ influx during the odorant response may ultimately play a role in terminating the response. One way Ca2+ inside the cell could terminate the odorant response would be to directly inhibit the cAMP-gated channels. In this report the effects of cytoplasmic Ca2+ and Mg2+ on the cAMP-activated current were measured in single olfactory cilia. Near the neuronal resting potential, cytoplasmic Ca2+ and Mg2+ only slightly reduced the cAMP-activated current. Even at high levels (1.0 mM Ca2+ or 5.0 mM Mg2+), the average inhibition was only around 20%. It is therefore unlikely that an influx of divalent cations terminates the odorant response by a direct effect on the cAMP-gated channels.
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Affiliation(s)
- S J Kleene
- Department of Anatomy and Cell Biology, University of Cincinnati, Ohio 45267-0521
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Zimmerman AL, Baylor DA. Cation interactions within the cyclic GMP-activated channel of retinal rods from the tiger salamander. J Physiol 1992; 449:759-83. [PMID: 1381754 PMCID: PMC1176105 DOI: 10.1113/jphysiol.1992.sp019112] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
1. The ionic dependence of current through the 3',5'-cyclic guanosine monophosphate (cyclic GMP)-activated channels of salamander rods was studied in excised inside-out membrane patches from isolated outer segments. Voltage-clamp experiments on transducing rods were performed so that the channels in intact cells could be compared with those in excised patches. 2. The reversal potential of the cyclic GMP-induced patch current was close to the Na+ equilibrium potential when the concentration of NaCl on the cytoplasmic surface of a patch was varied at constant external NaCl concentration. Fitting the Goldman-Hodgkin-Katz equation indicated that the apparent ratio of permeabilities for Na+ and Cl- was at least 50. This confirms a previous report that the channel's Na+ permeability is much larger than its Cl- permeability. 3. Na+ currents through the channel did not obey the independence principle. The outward patch current at large positive potential began to saturate with increasing concentrations of internal Na+, as if permeation required Na+ to bind to a site with an apparent dissociation constant around 180 mM. 4. In symmetrical NaCl solutions containing very low concentrations of divalent cations the current-voltage relation measured from excised patches 50 microseconds after switching the voltage showed mild outward rectification. By 1 ms the rectification was more pronounced. The rectification at 50 microseconds is attributed to voltage dependence of Na+ permeation. The additional rectification at later times is attributed to voltage dependence of the channel's probability of being open, depolarization favouring the open state. 5. In symmetrical Mg2+ solutions the cyclic GMP-induced patch currents were smaller and the outward rectification was more pronounced. 6. Addition of Mg2+ or Ca2+ to an internal Na+ solution blocked the cyclic GMP-induced Na+ current through the channels, as if by occupying a single binding site with an affinity in the 0.1-2 mM range. Block by Mg2+ was voltage dependent, suggesting that the binding site was within the channel's transmembrane electric field. Raising the Mg2+ concentration on the external surface of the patch increased the apparent dissociation constant of block by internal Mg2+, as expected if external and internal Mg2+ compete for the same binding site. 7. Block by internal Ca2+ had an opposite and weaker voltage dependence than block by internal Mg2+. 8. In symmetrical solutions containing both Na+ and Mg2+ the outward rectification was more pronounced than in solutions containing Na+ alone. In solutions thought to be close to physiological the outward patch current increased e-fold for a depolarization of 24-30 mV.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- A L Zimmerman
- Department of Neurobiology, Stanford University School of Medicine, CA 94305
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Latorre R, Bacigalupo J, Delgado R, Labarca P. Four cases of direct ion channel gating by cyclic nucleotides. J Bioenerg Biomembr 1991; 23:577-97. [PMID: 1655722 DOI: 10.1007/bf00785812] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Four different nucleotide-gated ion channels are discussed in terms of their biophysical properties and their importance in cell physiology. Channels activated directly by cGMP are present in vertebrate and invertebrate photoreceptors. In both cases cGMP increases the fraction of time the channel remains in the open state. At least three cGMP molecules are involved in channel opening in vertebrate photoreceptors and the concentration of the cyclic nucleotide to obtain the half maximal effect is about 15 microM. The light-dependent channel of both vertebrates and invertebrates is poorly cation selective. The vertebrate channel allows divalent cations to pass through 10-15-fold more easily than monovalent ions. In agreement with their preference for divalent cations, this channel is blocked by l-cis Dialtazem, a molecule that blocks certain types of calcium channels. In olfactory neurons a channel activated by both cAMP and cGMP is found and, as in the light-dependent channel, several molecules of the nucleotide are needed to open the channel with a half maximal effect obtained in the range of 1-40 microM. The channel is poorly cationic selective. A K+ channel directly and specifically activated by cAMP is found in Drosophila larval muscle. At least three cAMP molecules are involved in the opening reaction. Half-maximal effect is obtained at about 50 microM. This channel is blocked by micromolar amount of tetraethylammonium applied internally. Interestingly, this channel has a probability of opening 10-20-fold larger in the mutant dunce, a mutant that possesses abnormally elevated intracellular cAMP level, than in the wild type.
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Affiliation(s)
- R Latorre
- Centro de Estudios Cientificos de Santiago, Chile
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Filatova EA, Krapivinsky GB, Filatov GN, Lazareva AV, Fesenko EE. Antiidiotypic antibodies against anti-cGMP polyclonal antibodies. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1064:293-6. [PMID: 1645199 DOI: 10.1016/0005-2736(91)90314-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Affinity-purified polyclonal anti-cGMP antibodies were obtained from rabbit serum after immunization by succinyl derivative of cGMP coupled to bovine serum albumin. These antibodies were used to raise antiidiotypic antibodies in rats. Putative antiidiotypic serum inhibited the binding of [3H]cGMP to affinity-purified anti-cGMP antibodies. The influence of immunoglobulins isolated from antiidiotypic serum on the ion conductance of rod outer segment plasma membrane fragments from frog retina was studied in patch-clamp experiments. These immunoglobulins increased the conductance of ion channels acting like a natural agonist (cGMP). Preimmune immunoglobulins did not act. The data obtained suggest that antiidiotypic antibodies interact with regulatory cGMP-binding sites of the plasma membrane channels.
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Affiliation(s)
- E A Filatova
- Laboratory of Biophysics of the Reception, USSR Academy of Sciences, Pushchino, Moscow Region
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Volotovsky ID, Baranova LA, Khovratovich VI. Specific cGMP binding by retinal rod axoneme and its modulation by calcium ions and calmodulin. Exp Eye Res 1991; 52:389-92. [PMID: 1645272 DOI: 10.1016/0014-4835(91)90033-b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The high-affinity binding of cGMP to the retinal rod axoneme was identified. The axoneme was shown to contain two types of binding sites, with concentrations of 3.6 X 10(-10) and 5.8 X 10(-11) mol mg protein-1. The cGMP concentration for half-saturation of binding was 0.35 microM. The inhibition of cGMP binding by colchicine and vinblastine was 20% of Ca2+ and calmodulin control cGMP binding. The effect of calmodulin is explained by its interaction with specific binding sites which are possibly associated with Ca(2+)-induced depolymerization of axoneme microtubules.
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Affiliation(s)
- I D Volotovsky
- Institute of Photobiology, Byelorussian SSR Academy of Sciences, Minsk U.S.S.R
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Quandt FN, Nicol GD, Schnetkamp PP. Voltage-dependent gating and block of the cyclic-GMP-dependent current in bovine rod outer segments. Neuroscience 1991; 42:629-38. [PMID: 1659674 DOI: 10.1016/0306-4522(91)90032-j] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The properties of the cyclic-GMP-activated conductance in the plasma membrane of bovine rod outer segments were studied in excised membranes. Multiple-channel and single-channel currents were recorded by the patch-clamp technique in symmetrical NaCl solutions which were free of divalent cations. The current-voltage relationship for the current, recorded when a large population of channels was activated, exhibited outward rectification. Rectification decreased as the concentration of cyclic-GMP was increased, and the concentration of cyclic-GMP required for half maximal activation of the channel decreased with depolarization. At a concentration of 1-3 microM cyclic-GMP, single-channel activity could be observed from these excised patches. The conductance of the open channel was 6 pS and was independent of the membrane potential. These results are consistent with the interpretation that under these conditions, the mechanism responsible for the outward rectification is due to an increase in the probability of an open channel as the membrane is depolarized. The cyclic-GMP-activated current could be blocked by L-cis-diltiazem. Block was voltage and time dependent. The time constant for the onset of block and its steady state level increased with depolarization. The extent of block by diltiazem was not enhanced as the cyclic-GMP concentration was increased, suggesting that the channel is not required to be open for block to occur. Complete block was never attained even for high concentrations of diltiazem. However, the diltiazem-resistant component of the cyclic-GMP-activated current could be blocked by tetracaine.
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Affiliation(s)
- F N Quandt
- Lions Sight Centre, University of Calgary Faculty of Medicine, Alberta, Canada
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Rayer B, Naynert M, Stieve H. Phototransduction: different mechanisms in vertebrates and invertebrates. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1990; 7:107-48. [PMID: 2150859 DOI: 10.1016/1011-1344(90)85151-l] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The photoreceptor cells of invertebrate animals differ from those of vertebrates in morphology and physiology. Our present knowledge of the different structures and transduction mechanisms of the two animal groups is described. In invertebrates, rhodopsin is converted by light into a meta-rhodopsin which is thermally stable and is usually re-isomerized by light. In contrast, photoisomerization in vertebrates leads to dissociation of the chromophore from opsin, and a metabolic process is necessary to regenerate rhodopsin. The electrical signals of visual excitation have opposite character in vertebrates and invertebrates: the vertebrate photoreceptor cell is hyperpolarized because of a decrease in conductance and invertebrate photoreceptors are depolarized owing to an increase in conductance. Single-photon-evoked excitatory events, which are believed to be a result of concerted action (the opening in invertebrates and the closing in vertebrates) of many light-modulated cation channels, are very different in terms of size and time course of photoreceptors for invertebrates and vertebrates. In invertebrates, the single-photon events (bumps) produced under identical conditions vary greatly in delay (latency), time course and size. The multiphoton response to brighter stimuli is several times as long as a response evoked by a single photon. The single-photon response of vertebrates has a standard size, a standard latency and a standard time course, all three parameters showing relatively small variations. Responses to flashes containing several photons have a shape and time scale that are similar to the single-photon-evoked events, varying only by an amplitude scaling factor, but not in latency and time course. In both vertebrate and invertebrate photoreceptors the single-photon-evoked events become smaller (in size) and faster owing to light adaptation. Calcium is mainly involved in these adaptation phenomena. All light adaptation in vertebrates is primarily, or perhaps exclusively, attributable to calcium feedback. In invertebrates, cyclic AMP (cAMP) is apparently another controller of sensitivity in dark adaptation. The interaction of photoexcited rhodopsin with a G-protein is similar in both vertebrate and invertebrate photoreceptors. However, these G-proteins activate different photoreceptor enzymes (phosphodiesterases): phospholipase C in invertebrates and cGMP phosphodiesterase in vertebrates. In the photoreceptors of vertebrates light leads to a rapid hydrolysis of cGMP which results in closing of cation channels. At present, the identity of the internal terminal messenger in invertebrate photoreceptors is still unsolved.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- B Rayer
- Institut für Biologie II, RWTH Aachen, F.R.G
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Kolesnikov SS, Zhainazarov AB, Kosolapov AV. Cyclic nucleotide-activated channels in the frog olfactory receptor plasma membrane. FEBS Lett 1990; 266:96-8. [PMID: 1694788 DOI: 10.1016/0014-5793(90)81515-p] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Patch clamp technique was used to record cyclic nucleotide-dependent current of the frog olfactory receptor cell plasma membrane. Data obtained indicate that the channels passing this current are permeable to Ca2+ or Mg2+ and moderately selective for monovalent cations according to the sequence Li+, Na+, K+ greater than Rb+ greater than Cs+ and are effectively blocked by 1-cis-diltiazem and 3',4'-dichlorobenzamil. The conductance of single cyclic nucleotide-gated channels in solutions with low Ca2+ and Mg2+ content is about 19 pS. The results demonstrate that cyclic nucleotide-activated channels of olfactory receptor cells are virtually identical to photoreceptor ones.
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Affiliation(s)
- S S Kolesnikov
- Institute of Biological Physics, USSR Academy of Sciences, Pushchino, Moscow Region
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19
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Light DB, Corbin JD, Stanton BA. Dual ion-channel regulation by cyclic GMP and cyclic GMP-dependent protein kinase. Nature 1990; 344:336-9. [PMID: 1690355 DOI: 10.1038/344336a0] [Citation(s) in RCA: 176] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Atrial natriuretic peptide, acting through its second messenger guanosine 3',5'-cyclic monophosphate (cGMP), suppresses Na+ absorption across the renal inner-medullary collecting duct and increases urinary Na+ excretion. Patch clamp studies show that cGMP reduces Na+ absorption by inhibiting an amiloride-sensitive cation channel in the apical membrane. We have now examined, using the patch clamp technique, the molecular mechanisms of cGMP inhibition. Cyclic GMP directly and specifically reduced the probability of a single channel being open (open probability, Po) by 39% (inhibition constant, Ki = 7.6 x 10(-7) M) by a phosphorylation-independent mechanism. Cyclic GMP also inhibited the channel by activating cGMP-dependent protein kinase (cGMP-kinase). Exogenous cGMP-kinase completely inhibited the channel by a phosphorylation-dependent mechanism. Activation of a pertussis toxin-sensitive G protein by GTP-gamma-S blocked cGMP-kinase inhibition of the channel. By contrast, cGMP-kinase inhibition of Po was completely reversed by GTP-gamma-S. Taken together with the results of a previous study showing that a G protein activates the cation channel, these data indicate that cGMP-kinase and a G protein sequentially regulate the cation channel. Our results show that atrial natriuretic peptide, acting through cGMP, inhibits Na+ absorption across the inner-medullary collecting duct by a dual mechanism, and that cGMP-kinase inhibits the channel by a pathway involving a G protein.
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Affiliation(s)
- D B Light
- Department of Physiology, Dartmouth Medical School, Hanover, New Hampshire
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Zimmerman AL, Karpen JW, Kantrowitz-Gordon SE, Tsai CS, Stryer L, Baylor DA. Workings of the cGMP-activated channel of retinal rods. NEUROSCIENCE RESEARCH. SUPPLEMENT : THE OFFICIAL JOURNAL OF THE JAPAN NEUROSCIENCE SOCIETY 1990; 12:S165-74. [PMID: 1700848 DOI: 10.1016/0921-8696(90)90018-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- A L Zimmerman
- Section of Physiology and Biophysics, Brown University, Providence, RI 02912
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21
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Krapivinsky GB, Filatov GN, Filatova EA, Lyubarsky AL, Fesenko EE. Regulation of cGMP-dependent conductance in cytoplasmic membrane of rod outer segments by transducin. FEBS Lett 1989; 247:435-7. [PMID: 2469603 DOI: 10.1016/0014-5793(89)81386-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A preparation of the photoreceptor G-protein, transducin, containing mainly the T alpha-subunit in a GTP-gamma-S-bound form, has been used for perfusion of the intracellular surface of excised patches of rod outer segment cytoplasmic membrane from frog retina. The preparation has been shown to result in the complete suppression of the cGMP-activated ionic conductance of the cytoplasmic membrane patch. The effect is entirely reversible after the protein has been washed out and is not observed in the absence of cGMP. The degree of conductance inhibition depends on the protein concentration, half-maximal inhibition occurring at 1 microM T alpha-GTP-gamma-S.
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Affiliation(s)
- G B Krapivinsky
- Institute of Biological Physics, USSR Academy of Sciences, Pushchino, Moscow Region
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22
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Filatov GN, Jainazarov AB, Kolesnikov SS, Lyubarsky AL, Fesenko EE. The effect of ATP, GTP and cAMP on the cGMP-dependent conductance of the fragments from frog rod plasma membrane. FEBS Lett 1989; 245:185-8. [PMID: 2538357 DOI: 10.1016/0014-5793(89)80218-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Using a 'patch-clamp' method in the 'inside-out' configuration, ATP, ADP, AMP-PCP and AMP-PNP have been shown to increase the cGMP-dependent component of the rod plasma membrane conductance 2-4-fold and GTP, GDP but not GMP or nonhydrolyzable GTP analogs GMP-PNP and GTP-gamma-S to abolish the ATP action. The ATP and GTP effects were observed at [EDTA] = 1 mM when magnesium and calcium ions were absent. In about half of the experiments the cGMP-dependent conductance was shown to be increased by cAMP in the micromolar concentration range by 10-50%, the cAMP action did not depend on the presence of nucleoside triphosphates. In vivo ATP, GTP and cAMP are assumed to modulate the sensitivity of the photoreceptor plasma membrane to cGMP.
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Affiliation(s)
- G N Filatov
- Institute of Biological Physics, USSR Academy of Sciences, Pushchino, Moscow Region
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23
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Light DB, Schwiebert EM, Karlson KH, Stanton BA. Atrial natriuretic peptide inhibits a cation channel in renal inner medullary collecting duct cells. Science 1989; 243:383-5. [PMID: 2463673 DOI: 10.1126/science.2463673] [Citation(s) in RCA: 178] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The patch-clamp technique was used to examine the effects of atrial natriuretic peptide (ANP) and its second messenger guanosine 3',5'-monophosphate (cGMP) on an amiloride-sensitive cation channel in the apical membrane of renal inner medullary collecting duct cells. Both ANP (10(-11) M) and dibutyryl guanosine 3',5'-monophosphate (10(-4) M) inhibited the channel in cell-attached patches, and cGMP (10(-5) M) inhibited the channel in inside-out patches. The inner medullary collecting duct is the first tissue in which ANP, via its second messenger cGMP, has been shown to regulate single ion channels. The results suggest that the natriuretic action of ANP is related in part to cGMP-mediated inhibition of electrogenic Na+ absorption by the inner medullary collecting duct.
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Affiliation(s)
- D B Light
- Department of Physiology, Dartmouth Medical School, Hanover, NH 03756
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24
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Stoclet JC, Boulanger-Saunier C, Lassegue B, Lugnier C. Cyclic nucleotides and calcium regulation in heart and smooth muscle cells. Ann N Y Acad Sci 1988; 522:106-15. [PMID: 2837121 DOI: 10.1111/j.1749-6632.1988.tb33348.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- J C Stoclet
- UA CNRS 600, Faculty of Pharmacy, Louis Pasteur University, Strasbourg, France
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25
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Karpen JW, Zimmerman AL, Stryer L, Baylor DA. Gating kinetics of the cyclic-GMP-activated channel of retinal rods: flash photolysis and voltage-jump studies. Proc Natl Acad Sci U S A 1988; 85:1287-91. [PMID: 2448798 PMCID: PMC279752 DOI: 10.1073/pnas.85.4.1287] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The gating kinetics of the cGMP-activated cation channel of salamander retinal rods have been studied in excised membrane patches. Relaxations in patch current were observed after two kinds of perturbation: (i) fast jumps of cGMP concentration, generated by laser flash photolysis of a cGMP ester ("caged" cGMP), and (ii) membrane voltage jumps, which perturb activation of the channel by cGMP. In both methods the speed of activation increased with the final cGMP concentration. The results are explained by a simple kinetic model in which activation involves three sequential cGMP binding steps with bimolecular rate constants close to the diffusion-controlled limit; fully liganded channels undergo rapid open-closed transitions. Voltage perturbs activation by changing the rate constant for channel closing, which increases with hyperpolarization. Intramolecular transitions of the fully liganded channel limit the kinetics of activation at high cGMP concentrations (greater than 50 microM), whereas at physiological cGMP concentrations (less than 5 microM), the kinetics of activation are limited by the third cGMP binding step. The channel appears to be optimized for rapid responses to changes in cytoplasmic cGMP concentration.
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Affiliation(s)
- J W Karpen
- Department of Neurobiology, Sherman Fairchild Science Center, Stanford University School of Medicine, CA 94305
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26
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Hanke W, Cook NJ, Kaupp UB. cGMP-dependent channel protein from photoreceptor membranes: single-channel activity of the purified and reconstituted protein. Proc Natl Acad Sci U S A 1988; 85:94-8. [PMID: 2448771 PMCID: PMC279489 DOI: 10.1073/pnas.85.1.94] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The cGMP-dependent channel protein has been purified from bovine rod photoreceptor membranes and incorporated into planar lipid membranes. At low divalent cation concentrations, cGMP stimulated single-channel current fluctuations. The probability Po of the channel being open strongly depended on the cGMP concentration (EC50 = 31 microM; Hill coefficient, n = 2.3); whereas the single-channel conductance (lambda = 26 pS) was independent of the agonist concentration. The agonist-stimulated increase in the probability of an open channel was largely due to shorter closed times and, to a lesser extent, due to the channel staying open for a longer time. The current-voltage relationship of the single open channel deviated from ohmic behavior, and the open probability decreased at more negative membrane potentials. The rectification of the macroscopic cGMP-induced current in artificial bilayers that contained many channel copies can be accounted for by the voltage dependence of channel gating together with the nonlinearity of the current-voltage curve of an open channel. Current fluctuations exhibited a variety of sublevels, indicating that the channel may exist in more than one conductive state.
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Affiliation(s)
- W Hanke
- Fachbereich Biologie/Chemie, Abteilung Biophysik, Universität Osnabrück, Federal Republic of Germany
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27
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Koch KW, Cook NJ, Kaupp UB. The cGMP-dependent channel of vertebrate rod photoreceptors exists in two forms of different cGMP sensitivity and pharmacological behavior. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)47810-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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28
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Kolesnikov SS, Jainazarov AB, Fesenko EE. Time-dependent cGMP-activated conductance of detached patches of ROS plasma membrane. FEBS Lett 1987; 222:37-41. [PMID: 2820798 DOI: 10.1016/0014-5793(87)80187-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
cGMP markedly increases the cationic conductance of the 'inside-out' patches of rod outer segment plasma membrane when applied to the inner side. The cGMP-activated conductance of some patches was shown to be time-dependent. The data obtained suggest that the change of cGMP concentration in the near membrane layer underlies this phenomenon rather than the change in the channel's activity. The hydrolysis and, probably, the desorption of the nucleotide are responsible for this.
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Affiliation(s)
- S S Kolesnikov
- Institute of Biological Physics, USSR Academy of Sciences, Pushchino, Moscow Region
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