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Schirmer AE, Prete FR, Mantes ES, Urdiales AF, Bogue W. Circadian rhythms affect electroretinogram, compound eye color, striking behavior and locomotion of the praying mantis Hierodula patellifera. ACTA ACUST UNITED AC 2014; 217:3853-61. [PMID: 25214491 DOI: 10.1242/jeb.102947] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many behaviors and physiological processes oscillate with circadian rhythms that are synchronized to environmental cues (e.g. light onset), but persist with periods of ~24 h in the absence of such cues. We used a multilevel experimental approach to assess whether circadian rhythms modulate several aspects of the visual physiology and behavior of the praying mantis Hierodula patellifera. We used electroretinograms (ERGs) to assess compound eye sensitivity, colorimetric photographic analyses to assess compound eye color changes (screening pigment migration), behavioral assays of responsiveness to computer-generated prey-like visual stimuli and analyses of locomotor activity patterns on a modified treadmill apparatus. Our results indicate that circadian clocks control and/or modulate each of the target behaviors. Strong rhythms, persisting under constant conditions, with periods of ~24 h were evident in photoreceptor sensitivity to light, appetitive responsiveness to prey-like stimuli and gross locomotor activity. In the first two cases, responsiveness was highest during the subjective night and lowest during the subjective day. Locomotor activity was strongly clustered around the transition time from day to night. In addition, pigment migration and locomotor behavior responded strongly to light:dark cycles and anticipated the light-dark transition, suggesting that the circadian clocks modulating both were entrained to environmental light cues. Together, these data indicate that circadian rhythms operate at the cellular, cellular systems and organismal level in H. patellifera. Our results represent an intriguing first step in uncovering the complexities of circadian rhythms in the Mantodea.
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Affiliation(s)
- Aaron E Schirmer
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
| | - Frederick R Prete
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
| | - Edgar S Mantes
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
| | - Andrew F Urdiales
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
| | - Wil Bogue
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
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Poitry S, Widmer H. Kinetics of oxygen consumption after a flash of light in the lateral ocellus of the barnacle. Biophys J 2010; 54:655-67. [PMID: 19431731 DOI: 10.1016/s0006-3495(88)83001-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Until recently, polarographic methods for measuring the time course of transient changes in the rate of oxygen consumption (DeltaQO(2)) have been applied only to tissue preparations containing thousands of cells. Here, we describe DeltaQO(2) measurements on the lateral ocellus of the barnacle (Balanus eburneus) which contains only three photoreceptor cells. The decrement of partial pressure of oxygen (DeltaPO(2)) elicited by an 80 ms flash of light was measured near the cells with a microelectrode and the DeltaQO(2) was calculated from the DeltaPO(2) using a model of diffusion with spherical symmetry. As shown by mathematical simulation, the exact shape of the preparation is not crucial for our measurements of the time course of the DeltaQO(2). For a given DeltaQO(2), the model describes correctly the attenuation of the DeltaPO(2) measured at increased distances from the preparation. To know more about the mechanisms controlling the DeltaQO(2), we compared it with the electrical response of the photoreceptor cells: both responses have a similar spectral dependence, but only the DeltaQO(2) was abolished by a 10-min exposure to 50 muM dinitrophenol or to 3 mM amytal. We conclude that the DeltaQO(2) reflects an increase in mitochondrial respiration and that it is initiated by the phototransformation of rhodopsin, as was already found in the honeybee drone retina (Dimitracos and Tsacopoulos, 1985; Jones and Tsacopoulos, 1987).
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Nelson R, Bender AM, Connaughton VP. Stimulation of sodium pump restores membrane potential to neurons excited by glutamate in zebrafish distal retina. J Physiol 2003; 549:787-800. [PMID: 12730339 PMCID: PMC2342992 DOI: 10.1113/jphysiol.2003.042051] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Glutamate either depolarizes or hyperpolarizes retinal neurons. Those are the initial and primary effects. Using a voltage probe (oxonol, DiBaC4 (5)) to study dissociated zebrafish retinal neurons, we find a secondary, longer-term effect: a post-excitatory restoration of membrane potential, termed after-hyperpolarization (AHP). AHP occurs only in neurons that are depolarized by glutamate and typically peaks about 5 min after glutamate application. AHP is seen in dissociated horizontal cells (HCs) and hyperpolarizing, or OFF type, bipolar cells (HBCs). These cells commonly respond with only an AHP component. AHP never occurs in depolarizing, or ON type, bipolar cells (DBCs), which are cell types hyperpolarized by glutamate. AHP is blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). It is evoked by kainate, AMPA and the AMPA-selective agonist (S)-5-fluorowillardiine, but not by NMDA, D-aspartate, the kainate-selective agonist SYM 2081 or by DL-2-amino-4-phosphonobutyric acid (DL-AP4). Cells with exclusively AHP responses are tonically depolarized. Resting potentials can be restored by nifedipine, suggesting a tonic, depolarizing action of L-type Ca2+ channels. However AHP is not blocked by nifedipine and is insensitive to [Cl-]o. AHP is blocked by Li+o substitution for Na+o and by ouabain. A mechanism is proposed in which Na+ entering through ionotropic AMPA channels stimulates Na+,K+-ATPase, which, by electrogenic action, restores membrane potential, generating the AHP response. Patterns of ATPase immunoreactivity support localization in the outer plexiform layer (OPL) as cone pedicles, HCs and BCs were positively labelled. Labelling was weaker in the inner plexiform layer (IPL) than in nuclear layers, though two IPL bands of immunoreactive BC terminals could be discerned, one in sublamina a and the other in sublamina b. Persistent stimulation of distal retina by photoreceptor glutamate may induce increased expression and activity of Na+,K+-ATPase, with a consequent impact on distal glutamate responses.
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Affiliation(s)
- Ralph Nelson
- Basic Neurosciences Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Chapter 10 Modeling primary visual processes in insect photoreceptors. HANDBOOK OF BIOLOGICAL PHYSICS 2000. [DOI: 10.1016/s1383-8121(00)80013-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Werner U, Suss-Toby E, Rom A, Minke B. Calcium is necessary for light excitation in barnacle photoreceptors. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1992; 170:427-34. [PMID: 1625218 DOI: 10.1007/bf00191459] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Illumination of barnacle (Balanus amphitrite) photoreceptors is known to increase the membrane permeability to sodium and Ca2+ ions resulting in a depolarizing receptor potential. In this report, we show that lanthanum (La3+), a known inhibitor of Ca-binding proteins, reversibly eliminates the receptor potential of barnacle photoreceptors when applied to the extracellular space. Similar reversible elimination of the light response was obtained by removing extracellular Ca2+ by application of the calcium chelating agent EGTA. Iontophoretic injection of Ca2+, but not K+ into the cells protected both the transient and the steady-state phases of the receptor potential from elimination by EGTA while only the transient phase was protected in the presence of La3+. The EGTA experiments suggest that internal Ca2+ is necessary for light excitation of barnacle photoreceptors while the La3+ experiments suggest that La(3+)-sensitive inward current is necessary to maintain excitation during prolonged light.
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Affiliation(s)
- U Werner
- Department of Physiology, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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O'Day PM, Phillips CL. Effects of external lithium on the physiology of Limulus ventral photoreceptors. Vis Neurosci 1991; 7:251-8. [PMID: 1661136 DOI: 10.1017/s0952523800004065] [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: 12/28/2022]
Abstract
We have examined some of the physiological effects associated with the replacement of extracellular Na+ with Li+ in nominally Ca(2+)-free saline in the ventral photoreceptors of the horseshoe crab Limulus polyphemus. We observed that replacement of Na+ saline with Li+ saline induced larger voltage-activated inward currents with similar voltage dependence. These currents were absent in Tris+ saline. Anode-break excitation was maintained in Li+ saline but blocked in Tris+ saline. Regenerative events associated with quantum bumps in dark-adapted cells illuminated with dim lights were maintained in Li+ saline. Regenerative events associated with responses to moderately bright illumination were also maintained in Li+ saline. The post-illumination hyperpolarization associated with the Na+/K(+)-exchange pump (Brown & Lisman, 1972) was present after brief exposure to Li+ saline but disappeared after longer exposure. Following return to Na+ saline, the post-illumination hyperpolarization reappeared. We conclude that (1) Li+ permeates the voltage-dependent Na+ channel, GNa(V), in the photoreceptor plasma membrane; (2) Li+ supports voltage-activated physiological events normally mediated by Na+; and (3) Li+ substitution briefly supports and later inhibits the electrogenic effects of the Na+/K(+)-exchange pump. The effects of external Li+ on cellular physiology have implications for the interpretation of other studies employing Li+ extracellularly.
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Affiliation(s)
- P M O'Day
- Institute of Neuroscience, University of Oregon, Eugene
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Fein A, Tsacopoulos M. Light-induced oxygen consumption in Limulus ventral photoreceptors does not result from a rise in the intracellular sodium concentration. J Gen Physiol 1988; 91:515-27. [PMID: 2455766 PMCID: PMC2216144 DOI: 10.1085/jgp.91.4.515] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Illumination of Limulus ventral photoreceptors leads to an increase in the intracellular concentration of sodium, [Na+]i, and to an increase in the consumption of O2 (delta QO2). After a 1-s light flash, it takes approximately 480 s for [Na+]i to return to within 10% of its preillumination level, whereas delta QO2 takes approximately 90 s. Thus, the delta QO2 is complete long before [Na+]i has returned to its resting level. Pressure injection of Na+ into the cell in order to elevate [Na+]i to the same levels as attained by illumination causes a rise in [Na+]i that returns to baseline with the same time course as the light-induced rise in [Na+]i. However, the injection of Na+ does not lead to an increase of the consumption of O2. We conclude that activation of the Na pump by a rise in [Na+]i is not a factor involved in the light-induced activation of O2 consumption in these cells.
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Affiliation(s)
- A Fein
- Laboratory of Sensory Physiology, Marine Biological Laboratory, Woods Hole, Massachusetts 02543
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Almagor E, Hillman P, Minke B. Spatial properties of the prolonged depolarizing afterpotential in barnacle photoreceptors. I. The induction process. J Gen Physiol 1986; 87:391-405. [PMID: 3958692 PMCID: PMC2217611 DOI: 10.1085/jgp.87.3.391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In invertebrate photoreceptors, when the light stimulus results in substantial net transfer of the visual pigment from the rhodopsin (R) to the metarhodopsin (M) state, the ordinary late receptor potential (LRP) is followed by a prolonged depolarizing afterpotential (PDA). The dependence of the amplitude of the PDA on the amount of pigment conversion is strongly supralinear, and the PDA duration also depends on this amount. These observations indicate an interaction among the elements of the PDA induction process and also make possible a test of the range of this interaction. The test consists of a comparison of the PDA after localized pigment conversion, obtained by strong spot illumination, to that after weaker diffuse illumination converting a comparable total amount of pigment. The experiment was performed on the barnacle lateral eye. The effective spot size was measured by the early receptor potential (ERP), in seawater saturated with CO2, which considerably reduced the electrical coupling between the photoreceptors. The ERP was also used to determine whether there is diffusion of R molecules into the illuminated spot. The spot illumination induced a PDA with small amplitude and long duration, while no detectable PDA was induced by the diffuse light. This indicates that the range of the PDA interaction is much smaller than the entire cell. In addition, the ERP results showed that there was no detectable diffusion of R molecules into the illuminated spot area over 30 min. This measurement, with a calculated correction for the microvillar geometry of the photoreceptor, enabled us to put an upper limit on the diffusion coefficient of the pigment molecules in the inact, unfixed barnacle photoreceptor of D less than 6 X 10(-9) cm2 s-1.
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Hayashi JH, Moore JW, Stuart AE. Adaptation in the input-output relation of the synapse made by the barnacle's photoreceptor. J Physiol 1985; 368:179-95. [PMID: 3001295 PMCID: PMC1192591 DOI: 10.1113/jphysiol.1985.sp015852] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A study was made of synaptic transmission between the four median photoreceptors of the giant barnacle (Balanus nubilus) and their post-synaptic cells (I-cells). Simultaneous intracellular recordings were made from the presynaptic terminal region of a photoreceptor and from the soma of an I-cell. The photoreceptor's membrane potential provided feed-back to bath electrodes that passed current into the receptors' axons, permitting the voltage to be controlled at the point of arborization of their presynaptic terminals. Simultaneous recordings from a second photoreceptor showed that its voltage tracked the first. Step depolarizations of the receptors from their dark resting potential (about -60 mV) caused hyperpolarizations of the I-cell that reached a peak, then decayed to a plateau value. The amplitude of the I-cell's response grew with presynaptic depolarizations, saturating at presynaptic values 10-20 mV depolarized from dark rest. Step hyperpolarizations of the receptors from dark rest evoked depolarizations of the I-cell consisting of an initial peak, which varied greatly in amplitude and wave form from preparation to preparation, followed by a plateau. The presence of this post-synaptic response indicates that transmitter is released continuously from the receptors at their dark resting potential. An input-output relation of the synapse was obtained by presenting step depolarizations from a holding potential of -80 mV, where steady-state transmitter release is shut off. The relation is sigmoidal; in the exponentially rising phase of the curve, a 5-11 mV presynaptic change produces a 10-fold change in post-synaptic response. When the presynaptic holding potential was set at values ranging from -80 to -40 mV, the relation between the I-cell's response and the absolute potential to which the receptor was stepped shifted along the presynaptic voltage axis. The slopes of the input-output relations were roughly parallel or increased as the photoreceptors were held more depolarized. This observation limits the possible mechanisms of the shift.
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Abstract
Illumination of white-eyed Musca photoreceptors following hypoxia or the application of ruthenium red (RR, a known blocker of Ca2+ uptake into intracellular organelles) induced a transient after depolarization (TA). The TA was enhanced when external [Ca2+] was reduced; it was abolished when external [Na+] was reduced to a level that affected the receptor potential to a small degree. The TA was enhanced or depressed when the activity of Na/K pump, which controls the Na+ gradient, was enhanced or depressed respectively. This effect was observed even when the receptor potential was not affected. All of the above observations are consistent with the hypothesis that the TA is triggered by a light-induced increase in the concentration of intracellular free Ca2+ which appear to be very high, following treatments with hypoxia or RR. The high sensitivity of the TA to Na+ and Ca2+ gradients across the photoreceptors membrane strongly suggests that the TA is due to a transient activation of an electrogenic Na-Ca exchange mechanism which depolarizes the cell.
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Non-local interactions between light induced processes inCalliphora photoreceptors. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1984. [DOI: 10.1007/bf00604983] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Cornwall MC, Gorman AL. Colour dependence of the early receptor potential and late receptor potential in scallop distal photoreceptor. J Physiol 1983; 340:307-34. [PMID: 6887052 PMCID: PMC1199211 DOI: 10.1113/jphysiol.1983.sp014764] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
1. Intracellular voltage and current responses to short (blue) and long (red) wave-length lights were measured in the distal hyperpolarizing photoreceptor (;off receptor') of the isolated and perfused scallop (Pecten irradians) retina.2. The early receptor potential (e.r.p.) was isolated by holding membrane potential at the reversal potential for the late receptor potential (l.r.p.) or by working at temperatures (< 5.0 degrees C) that abolished the l.r.p.3. The e.r.p., measured using intense flashes of white light, consisted of a positive phase followed by a negative phase, but was converted to a monophasic, negative-going wave following pre-adaptation with red light and to a monophasic, positive-going wave following pre-adaptation with blue light.4. The spectral sensitivity curve for the negative e.r.p. was maximum at 500 nm, whereas the spectral sensitivity curve for the positive e.r.p. was maximum at 575 nm.5. The positive or negative e.r.p.s approached their maximum amplitude exponentially when tested with red or blue flashes of increasing intensity. The results suggest that the positive (or negative) e.r.p. is proportional to the number of photopigment molecules photo-isomerized.6. The photosensitivity maximum of rhodopsin calculated at 500 nm, using the exponential constant and the spectral sensitivity data, was estimated to be 2.1 x 10(-16) cm(2) photon(-1), whereas the photosensitivity maximum of metarhodopsin calculated at 575 nm was estimated to be 2.6 x 10(-16) cm(2) photon(-1).7. In cells pre-adapted with white light, stimulation with blue light caused a hyperpolarizing l.r.p. which was followed by a prolonged hyperpolarizing after-potential (p.h.a.). Stimulation with red light under similar conditions caused an initial hyperpolarization which was followed by a small depolarization during the stimulus, but no after-potential.8. The duration of the p.h.a. was increased by pre-adaptation with a red light, which caused the maximum net transfer of metarhodopsin to rhodopsin; however, its decay was always complete in 5 min or less.9. The photo-isomerization of metarhodopsin by red light suppressed the p.h.a. and caused an after-depolarizing response that decayed in less than 1 min.10. The spectral sensitivity curve for the induction of the p.h.a. was maximum at 500 nm and corresponded to the spectral sensitivity for the negative e.r.p. and for the l.r.p. studied in the dark-adapted retina, whereas the spectral sensitivity curve for the suppression of the p.h.a. and for the induction of the after-depolarization was maximum at 575 nm and corresponded to the spectral sensitivity for the positive e.r.p.11. In photoreceptors clamped to the resting potential in normal ASW, the photo-isomerization of rhodopsin, in the absence of light absorption by metarhodopsin, activated a persistent outward current that had the same time course of decay as the p.h.a. The photo-isomerization of metarhodopsin suppressed the persistent outward current and activated an inward current whose decay took longer than the decay of the after-depolarizing response.12. In the absence of external Ca(2+) and Na(+) ions, the persistent outward current produced by light absorption by rhodopsin, and the inward current produced by light absorption by metarhodopsin, both reversed at the K(+) equilibrium potential. The results show that the induction of the prolonged hyperpolarizing after-potential and the after-depolarizing response involve only the movement of K(+) ions through the same light-dependent K(+) channels that determine the hyperpolarizing l.r.p. of the distal cells.
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Tsacopoulos M, Orkand RK, Coles JA, Levy S, Poitry S. Oxygen uptake occurs faster than sodium pumping in bee retina after a light flash. Nature 1983; 301:604-6. [PMID: 6828139 DOI: 10.1038/301604a0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
When neurones are active there is an entry of Na+, which must subsequently be pumped out, and an increase in their oxygen consumption rate (Qo2). The Na+ pump derives its energy from ATP, splitting it into ADP and Pi, and it has reasonably been proposed that the changes in concentrations of ATP, ADP and Pi lead to a stimulation of the O2 consumption by the mitochondria and hence to a restoration of the stock of ATP. Here we present evidence suggesting that Qo2 must be controlled differently in the retinal photoreceptor cells of the honeybee drone. Stimulation of drone photoreceptors with a flash of light causes an entry of Na+ (ref. 4) and a transient increase in Qo2 that indicates respiration of the right order of magnitude to provide ATP to pump the Na+ out. We report intracellular recordings of changes in intracellular sodium (Nai+) and potassium (Ki+) in response to single light flashes and have compared the time course of extra oxygen consumption (delta Qo2) with these ion changes and other indices of Na+ pumping. We found that the time course of pumping seems to lag behind the time course of delta Qo2. It follows that the mitochondrial respiration must be stimulated by some signal which is generated earlier than the rise in ADP produced by the Na+ pump.
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Armon E, Minke B. Light activated electrogenic Na+-Ca2+-exchange in fly photoreceptors: Modulation by Na+/K+-pump activity. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/bf00535670] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Changes in the intensity-response function of an insect's photoreceptors due to light adaptation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1981. [DOI: 10.1007/bf00605031] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Edgington DR, Stuart AE. Properties of tetraethylammonium ion-resistant K+ channels in the photoreceptor membrane of the giant barnacle. J Gen Physiol 1981; 77:629-46. [PMID: 6267163 PMCID: PMC2215445 DOI: 10.1085/jgp.77.6.629] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
After the offset of illumination, barnacle photoreceptors undergo a large hyperpolarization that lasts seconds or minutes. We studied the mechanisms that generate this afterpotential by recording afterpotentials intracellularly from the medial photoreceptors of the giant barnacle Balanus nubilus. The afterpotential has two components with different time-courses: (a) an earlier component due to an increase in conductance to K+ that is not blocked by extracellular tetraethylammonium ion (TEA+) or 3-aminopyridine (3-AP) and (b) a later component that is sensitive to cardiac glycosides and that requires extracellular K+, suggesting that it is due to an electrogenic Na+ pump. The K+ conductance component increases in amplitude with increasing CA++ concentration and is inhibited by extracellular Co++; the Co++ inhibition can be overcome by increasing the Ca++ concentration. Thus, the K+ conductance component is Ca++ dependent. An afterpotential similar to that evoked by a brief flash of light is generated by depolarization with current in the dark and by eliciting Ca++ action potentials in the presence of TEA+ in the soma, axon, or terminal regions of the photoreceptor. The action potential undershoot is generated by an increase in conductance to K+ that is resistant to TEA+ and 3-AP and inhibited by Co++. The similarity in time-course and pharmacology of the hyperpolarization afterpotentials elicited by (a) a brief flash of light, (b) depolarization with current, and (c) an action potential indicates that Ca++-dependent K+ channels throughout the photoreceptor membrane are responsible for all three hyperpolarizing events.
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Laughlin S. Neural Principles in the Peripheral Visual Systems of Invertebrates. COMPARATIVE PHYSIOLOGY AND EVOLUTION OF VISION IN INVERTEBRATES 1981. [DOI: 10.1007/978-3-642-66907-1_2] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Koike H, Tsuda K. Cellular synthesis and axonal transport of gamma-aminobutyric acid in a photoreceptor cell of the barnacle. J Physiol 1980; 305:125-38. [PMID: 6160239 PMCID: PMC1282963 DOI: 10.1113/jphysiol.1980.sp013354] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
1. [3H]glutamate or [3H]gamma-aminobutyric acid (GABA) was injected into the photoreceptor cell of the lateral ocellus of Balanus eburneus, in order to study the transmitter substance of the cell. 2. The photoreceptor cell synthesized [3H]GABA from injected [3H]glutamate. 3. The newly formed [3H]GABA moved inside the photoreceptor axon towards the axon terminal with a velocity of about 0.9 mm/hr. Injected [3H]GABA moved at 0.9 mm/hr and also at 0.4 mm/hr. 4. Axonally transported [3H]GABA reached the axon terminal within several hours following the injection. It did not accumulate at the terminal, but gradually disappeared. 5. Light-microscope and electron-microscope autoradiography following the injection of [3H]GABA revealed that [3H]-reacted silver grains were present in a certain type of axon terminal. The terminal thus identified as that of a photoreceptor cell contains many clear, polymorphic synaptic vesicles about 300-500 A in diameter, some dense-cored vesicles 700-1300 A in diameter, and glycogen granules. The terminal forms many synapses, and each synapse has a synaptic dense body. The terminal always faces two post-synaptic elements at the synapse, forming a triad with a gap distance of about 160-200 A. 6. A GABA analogue, [3H]di-aminobutyric acid, was selectively taken up into the terminals previously identified as those of photoreceptors. 7. These results support the notion that the transmitter substance of the photoreceptor cell of the barnacle is GABA.
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Brown HM, Meech RW. Light induced changes of internal pH in a barnacle photoreceptor and the effect of internal pH on the receptor potential. J Physiol 1979; 297:73-93. [PMID: 43890 PMCID: PMC1458708 DOI: 10.1113/jphysiol.1979.sp013028] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
1. Intracellular pH (pH1) was measured in Balanus photoreceptors using pH-sensitive glass micro-electrodes. The average pH1 of twelve photoreceptors which had been dark adapted for at least 30 min was 7.3 +/- 0.07 (S.D.). 2. Illumination reduced the recorded pH1 by as much as 0.2 pH unit. The change in pH1 was graded with light intensity. 3. When the cells were exposed to CO2 in the dark, pH1 declined monophasically. Saline equilibrated with 2% CO2; 98% O2 produced a steady reduction in pH1 of about 0.25 unit in 2--3 min. The buffering capacity of the receptor cell cytoplasm calculated from such experiments is approximately 15 slykes. 4. In the presence of HCO3-1, CO2 saline produced smaller, biphasic changes in pH1. 5. The membrane depolarization produced by a bright flash (depolarizing receptor potential) was reversibly reduced in the presence of external CO2 or by injection of H+. Iontophoretic injection of HCO2- increased the amplitude of the receptor potential. 6. In individual cells there was a close correlation between the amplitude of the receptor potential and pH1. 7. Saline equilibrated with CO2 reduced the light induced current (recorded under voltage-clamp) by 40--50% without affecting its reversal potential. 8. Exposure of the receptor to 95% CO2 saline for several minutes (pH0 5.5) not only abolished the receptor potential but also reversibly decreased the K conductance of the membrane in the dark. These effects were not reproduced by pH0 5.5 buffered saline or by a 5 min exposure to saline equilibrated with N2. 9. It is suggested that changes in pH1 induced by light modulate the sensitivity of the receptor under physiological conditions.
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The receptor potential of retinular cells of the blowflyCalliphora: The role of sodium, potassium and calcium ions. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1979. [DOI: 10.1007/bf00617735] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Fein A, Charlton JS. Increased intracellular sodium mimics some but not all aspects of photoreceptor adaptation in the ventral eye of Limulus. J Gen Physiol 1977; 70:601-20. [PMID: 591914 PMCID: PMC2228471 DOI: 10.1085/jgp.70.5.601] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The effects of the intracellular iontophoretic injection of Na+ ions have been quantitatively compared with adaptation in ventral photoreceptors of Limulus. We find that: (a) both light adaptation and sodium injection are associated with a decrease in the variability of the threshold response amplitued; (b) both light adaptation and sodium injection are associated with a decrease in the absolute value of the temporal dispersion of the threshold response time delay; (c) the same template curve adequately fits the intensity response relationships measured under light adaptation and Na+ injection; (d) both light adaptation and Na+ injection produce a fourfold decrease in response time delay for a desensitization of 3 log units; (e) the time coures of light adaptation and dark adaptation is significantly faster than the onset of and recovery from desensitization produced by Na+ injection; (f) unlike local illumination, Na+ injection does not produce localized desensitization of the photoreceptor. These findings suggest that a rise in intracellular Na+ concentration makes at most only a minor contribution (probably less than 5%) to the total adaptation of these receptors in the intensity range we have examined (up to 3 log units above absolute threshold). However, changes in intracellular Na+ concentration may contribute to certain components of light and dark adaptation in these receptors.
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Hudspeth AJ, Poo MM, Stuart AE. Passive signal propagation and membrane properties in median photoreceptors of the giant barnacle. J Physiol 1977; 272:25-43. [PMID: 592129 PMCID: PMC1353591 DOI: 10.1113/jphysiol.1977.sp012032] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
1. The light-induced electrical responses of barnacle photoreceptors spread decrementally along the cells' axons. The decay of the depolarizing and hyperpolarizing components of the visual signal was studied by recording intracellularly from single receptor axons of the median ocellus of the giant barnacle.2. The resistance of the photoreceptor neurone decreases markedly when the cell is depolarized with respect to its dark resting potential of -60 mV. This rectification results in differential attenuation of the depolarizing and hyperpolarizing components of the visual signal as they spread down the axon. Consequently, the visual signal entering the synaptic region is conspicuously distorted.3. Bathing the photoreceptor axons in sodium-free or calcium-free saline or in isotonic sucrose does not significantly affect the spread of the visual signal to the terminals. Thus the signal is not amplified by an ionic mechanism along the axon.4. Membrane characteristics of the photoreceptor for hyperpolarizing voltage changes were estimated from (a) the ratio of the amplitudes of the visual signals recorded simultaneously in the axon and in the soma, (b) the time constant, and (c) the input resistance of the cell. All three independent measurements are consistent with a length constant 1 to 2 times the total length of the cell (lambda = 10-18 mm) and an unusually high membrane resistivity of about 300 kOmega cm(2). This resistivity enables the receptor potential to spread passively to the terminal region.5. Electron microscopic examination of receptor axons reveals an investment of glial lamellae, but demonstrates neither unusual structures which would lead to a high apparent membrane resistivity, nor junctions between cells which would seal off the extracellular space. Thus the observed high resistivity appears to be an intrinsic property of the receptor membrane.
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Hudspeth AJ, Stuart AE. Morphology and responses to light of the somata, axons, and terminal regions of individual photoreceptors of the giant barnacle. J Physiol 1977; 272:1-23. [PMID: 592112 PMCID: PMC1353590 DOI: 10.1113/jphysiol.1977.sp012031] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
1. The median eye of the giant barnacle, B. nubilus, comprises four large photoreceptor neurones which are visible under the dissecting microscope for almost their entire length. We have studied the structure of, and the responses to light recorded in, the somata, axons, and terminal regions of these neurones.2. The photoreceptor somata, each 40-70 mum in diameter, extend numerous light-sensitive dendritic processes whose membranes form rhabdomeric microvilli. Recordings from the soma show that dim light evokes a steady, noisy depolarization; brighter light elicits a transient depolarization which decays to a maintained plateau, followed by a hyperpolarization when the light is turned off.3. Light-induced voltage changes spread decrementally along the photoreceptor axons, which average 10 mm in length and 25 mum in diameter. In distal parts of the axon, near the presynaptic terminals, depolarizations and hyperpolarizations can be as large as 50% or more of their values in the soma.4. There is no demonstrable electrical coupling between photoreceptor neurones as shown by simultaneous recordings from two receptor somata or axons.5. Each photoreceptor axon enters the mid line commissure of the supraoesophageal ganglion, bifurcates, and arborizes in a restricted zone of neuropil in each hemiganglion. The large size of the terminal processes of these neurones and their characteristic cytoplasmic inclusions enable one to trace them with the electron microscope as they branch in the neuropil.6. The terminal processes subdivide and end in 1-3 mum diameter branches which are the sites of apparently chemical synapses. Vesicle-containing, presynaptic loci on these processes of the receptor cell are invariably apposed to two post-synaptic processes from cells as yet unidentified.
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Abstract
1. Intracellular recording from photoreceptors in the lateral eye of the barnacle show a brief negative-going 'dip' shortly after the onset of the late receptor potential. This phase can sometimes result in a hyperpolarization relative to the resting membrane potential. 2. The dip is prominent in light-adapted cells and is reduced by dark-adaptation. Low extracellular Ca2+ also reduces it. 3. The amplitude of the dip changes inversely with the K+ concentration in the saline. 4. The amplitude of the dip depends on the membrane potential, with a reversal potential near - 80 mV. 5. K+ blocking agents such as quinine and quinidine reduce or abolish the dip. 6. These observations indicate that the dip is due to a brief increase in K+ conductance which may be dependent on an influx of Ca ions. The fast decay of this phase may be brought about by a rapid uptake of Ca2+ by an intracellular mechanism.
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Taglietti V, Rossi ML, Casella C. Adaptive distortions in the generator potential of semicircular canal sensory afferents. Brain Res 1977; 123:41-57. [PMID: 300266 DOI: 10.1016/0006-8993(77)90642-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The generator potential in sensory afferents of frog crista ampullaris was extracellularly recorded from the cut end of the posterior ampullary nerve by means of suction electrodes. A servocontrolled turntable allowed suitable rotatary stimulations. The analysis of the recorded generator potential revealed a different time course from that predicted on the basis of the pendulum model. Adaptation and undershoots in the responses to velocity ramps, steps and sinusoids, were mainly responsible for the deviations, which became very evident only when fairly high acceleration rates were applied. Both adaptation and undershoots were produced presumably by the activation of an electrogenic pump, probably located in nerv terminals contacting the hair cells. In fact, the time course of the generator potential became much more consistent with the predictions from the pendulum model under treatments capable of hindering the ion pump activity.
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Dahl RD, Krischer CC, Meissen R, Rittinghaus KF. Early receptor potentials and comparison of the electrical properties of median and lateral photoreceptors of the barnacle. Vision Res 1977; 17:519-25. [PMID: 888363 DOI: 10.1016/0042-6989(77)90050-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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29
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Intracellular recordings from photoreceptors of the squid (Loligo pealii). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1977. [DOI: 10.1007/bf00611893] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Eyzaguirre C, Nishi K. Effects of different ions on resting polarization and on the mass receptor potential of carotid body chemosensors. JOURNAL OF NEUROBIOLOGY 1976; 7:417-34. [PMID: 978203 DOI: 10.1002/neu.480070505] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The carotid body and its own nerve were removed from cats anesthetized with sodium pentobarbital and placed in an air gap system; the carotid body was bathed in modified Locke's solution equilibrated with 50% O2 in N2, pH 7.43 at 35 degrees C. The sensory discharges, changes in "resting" receptor polarization and the mass receptor potential evoked by ACh or NaCN were recorded with nonpolarizable electrodes placed across the gap. Receptor potentials and sensory discharges evoked by ACh showed an appreciable increase in amplitude and frequency when the preparation was bathed in eserinized Locke. Eserine did not change appreciably the responses evoked by NaCN. Excessive depolarization elicited by either ACh or NaCN was accompanied by sensory discharge block. Removal of K+ ions from the bathing solution induced receptor hyperpolarization and an increase in the amplitude of the evoked receptor potentials. An increase of K+ concentration had the opposite effect. Reduction of Na+ or NaCl to one half, or total removal of this salt, induced an initial reduction and later disappearance of the sensory discharges, some receptor hyperpolarization and a reduction in the amplitude of the evoked receptor potential. Reduction or removal of Ca++ produced receptor depolarization, a marked depression of the evoked receptor potentials, an increase in the frequency of the sensory discharges and a reduction in the amplitude of the nerve action potentials. High Ca++ or Mg++ had little or no effect on action potential amplitude or resting polarization, but decreased sensory discharge frequency and the evoked receptor potentials. Total or partial replacement of Ca++ with Mg++ induced complex effects: (1) receptor depolarization which occurred in low Ca++, was prevented by addition of Mg++ ions; (2) the amplitude of the evoked receptor potentials was depressed; (3) the nerve discharge frequency was reduced as it was in high Mg++ solutions; and (4) the amplitude of the nerve action potentials was reduced as it was in low Ca++ solutions. Temperature had a marked effect on the chemoreceptors since at high temperatures the receptors were depolarized and the discharge frequency increased. The baseline discharge and responses evoked by ACh or NaCN were depressed at low temperatures. The results are discussed in terms of possible receptor mechanisms influenced by the different ions.
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Brown HM, Ottoson D. Dual role for potassium in Balanus photoreceptor: antagonist of calcium and suppression of light-induced current. J Physiol 1976; 257:355-78. [PMID: 950598 PMCID: PMC1309364 DOI: 10.1113/jphysiol.1976.sp011373] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
1. The mechanism of reduction and final abolition of the depolarizing receptor potential of Balanus eburneus photoreceptors in K+-free saline was examined with electro-physiological techniques including voltage-clamp and ion specific electrodes. 2. An extended exposure to K+-free saline reduces the transient peak and the steady phases of the depolarizing receptor potential by approximately equal amounts. The process can be reversed in normal saline although the wave form of the response is often more rectangular upon recovery. Restoration of K+ induces a transient hyperpolarization of the resting membrane for several minutes. 3. The depolarizing receptor potential can also be restored in K+-free solution by reducing the Ca2+ concentration. This saline depolarizes the resting membrane, and the wave form of the depolarizing receptor potential assumes a rectangular configuration. 4. Voltage-clamp experiments revealed that an extended exposure to K+-free saline produced an extreme reduction of the inward light-induced current (LIC), but no detectable change in the membrane potential at which the current reverses sign. Membrane conductance in darkness showed little change. Reduction of the Ca2+ concentration from 20 to 0-2 mM in K+-free restored the current and produced a negative 8-10 mV shift in the zero current potential. There was also a significant decrease in membrane conductance in darkness. 5. Current-voltage relations of the membrane in K+-free, low Ca2+, or K+-free low Ca2+ salines were somewhat dependent upon the order the salines were presented. 6. Low Ca2+ saline (0-2 mM) by itself produced a -5 mV shift in the zero-current potential. Removing K+ in low Ca2+ produced an additional shift (-5 mV) in the zero-current potential.
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Abstract
The barnacle photoreceptor sensitivity may either decrease (light adaptation) or increase (facilitation) after exposure to a conditioning light. The balance between adaptation and facilitation is influenced by at least three factors: initial sensitivity state of the cell, external calcium concentration, and conditioning intensity. Cells of very high sensitivity show mainly adaptation, which appears only for higher conditioning intensities and is suppressed in low-calcium media. Less sensitive cells, or those whose sensitivity is reduced by injury or metabolic decay, exhibit facilitation, expecially in low-calcium media and at intermediate conditioning intensities. Both phenomena show recovery time-courses of seconds-to-minutes. Models are proposed which relate light adaptation, as previously suggested, to increased internal calcium concentration, and facilitation either to decreased internal calcium concentration or to decreased activation "affinity" of ion-channel-blocking sites.
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33
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Role of active ion transport in reception of the generator potential of the isolated frog muscle spindle. NEUROPHYSIOLOGY+ 1976. [DOI: 10.1007/bf01063246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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MEECH ROBERTW, BROWN HMACK. INVERTEBRATE PHOTORECEPTORS: A SURVEY OF RECENT EXPERIMENTS ON PHOTORECEPTORS FROM BALANUS AND LIMULUS. ZOOLOGY 1976. [DOI: 10.1016/b978-0-08-018767-9.50034-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Chase R. The electrophysiology of transduction, retinal interaction and axonal conduction in invertebrate photoreceptors. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1975; 52:571-6. [PMID: 1174 DOI: 10.1016/s0300-9629(75)80001-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Hunt CC, Ottoson D. Impulse activity and receptor potential of primary and secondary endings of isolated mammalian muscle spindles. J Physiol 1975; 252:259-81. [PMID: 127835 PMCID: PMC1348477 DOI: 10.1113/jphysiol.1975.sp011143] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
1. An isolated muscle spindle preparation from a tail muscle of cat is described. The afferent response to a ramp-and-hold stretch was recorded in individual axons from identified primary and secondary endings. 2. Primary endings exhibit a prominent dynamic response, including an initial burst. They also show a well-maintained static discharge. Secondary endings also show a well-sustained static discharge but generally have a much lower dynamic sensitivity. The response of primary and secondary endings of the isolated spindle are similar to the typical responses seen in vivo in groups Ia or group II afferent fibres respectively. 3. Following impulse blockade by tetrodotoxin, the receptor potential was recorded from primary and from secondary endings in response to ramp-and-hold stretch. 4. During the dynamic phase the receptor potential of primary endings consists of a depolarization which has two components. (a) An initial component occurs early during ramp stretch, depends in rate of rise and amplitude on velocity of stretch and is reduced on repetitive stretch; it appears to be responsible for the initial burst. (b) A late dynamic component, which follows, is also dependent on stretch velocity and produces the late dynamic discharge. At the end of ramp stretch the receptor potential falls, and may undershoot, the static level. There is a subsequent adaptive fall during hold stretch, then a maintained static level of receptor potential. On release from stretch the membrane is hyperpolarized. 5. Secondary endings usually show a smaller dynamic response, lacking the initial component seen in primary endings. They also generally lack an undershoot following the ramp and have less of a post-release hyperpolarization. 6. Static levels of receptor potential in both primary and secondary endings are related to amplitude of stretch. 7. The receptor potentials of primary and secondary endings account for the major features of the impulse responses of these endings to ramp-and-hold stretch. In primary endings the dynamic frequencies may also depend upon a sensitivity of the impulse initiating site to rate of change of receptor current.
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37
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Dudek FE. Analysis of "off" latency in insect photoreceptors. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1975; 51:845-7. [PMID: 237686 DOI: 10.1016/0300-9629(75)90064-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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Brown HM, Cornwall MC. Ionic mechanism of a quasi-stable depolarization in barnacle photoreceptor following red light. J Physiol 1975; 248:579-93. [PMID: 1151838 PMCID: PMC1309540 DOI: 10.1113/jphysiol.1975.sp010989] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
1. The membrane mechanism of a quasi-stable membrane depolarization (latch-up) that persists in darkness following red light was examined in barnacle photoreceptor with micro-electrode techniques including voltage-clamp and Na+-sensitive micro-electrodes. 2. Current-voltage (I-V) relations of the membrane in darkness following red light (latch-up) and in darkness following termination of latch-up with green light, indicate that latch-up is associated with an increase of membrane conductance. 3. The latch-current (membrane current in darkness following red light minus membrane current in darkness following a gree flash that terminates latch-up) was inward at the resting potential, reversed sign at about +26mV (mean of six cells), and became outward at more positive membrance potentials. 4. Current-voltage relations of the membrane during green light (no latch-up) closely resembled those during latch-up. The light-induced current (LIC) elicited by green ligh (membrane current during the light flash minus membrane current in darkness following the light flash) was inward from the resting potential to +26mV (mean of six cells), then reversed sign and became outward. 5. The latch-current and LIC were both augmented in reduced Ca2+ solutions and decreased as Na-+ was reduced at a fixed Ca2+ concentration. 6. Both LIC and latch-current reversed sign at a more negative membrane potential (increment V equals 14mV) in solutions containing one quarter the normal amount of Na+. 7. The internal Na-+ activity (a-iNa) of a photoreceptor increased from about 10-18 mM upon illumination with long steps of intense red or white illumination. Five minutes in darkness after white light, a-iNa had recovered significantly, whereas a-iNa remained elecated following red illumination. 8. Latch-up seems to be a persistence in darkness of the same membrane mechanism that normally occurs during illumination; i.e. a conductance increase to Na+ ions. Ca2+ ions act primarily to suppress this current. There is evidence for a net Na+ influx during illumination that is sustained in darkness during latch-up.
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Brown HM, Cornwall MC. Spectral correlates of a quasi-stable depolarization in barnacle photoreceptor following red light. J Physiol 1975; 248:555-78. [PMID: 1151837 PMCID: PMC1309539 DOI: 10.1113/jphysiol.1975.sp010988] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
1. Illumination of B. eburneus photoreceptors with intense red light produces a membrane depolarization that persists in darkness. This quasistable depolarization (latch-up) can be terminated with green light. The phenomenon was investigated with electrophysiological, spectrochemical, and microspectrophotometric techniques. 2. Latch-up was associated with a stable inward current in cells with the membrane potential voltage-clamped at the resting potential in darkness. The stable current could only be elicited at wave-lengths greater than 580 nm. 3. Light-induced current (LIC) was measured at various wave-lengths in dark-adapted photoreceptors with the membrane voltage-clamped to the resting potential. The minimum number of photons required to elicit a fixed amount of LIC occurred at 540 nm, indicating that the photoreceptor is maximally sensitive to this wave-length of light. The photoreceptor was also sensitive to wave-lengths in the near-U.V. region of the spectrum (380-420 nm). 4. Steady red adapting light reduced the magnitude of the LIC uniformly at all wave-lengths except in the near-U.V. region of the spectrum; sensitivity was reduced less in this region. 5. The spectrum for termination of the stable inward current following or during red light was shifted to the blue (peak about 510 nm) compared to the peak for LIC (peak about 540 nm). 6. Absorbance of single cells prepared under bright, red light decreased maximally at 480 nm following exposure to wave-lengths of light longer than 540 nm. 7. A pigment extract of 1000 barnacle ocelli prepared under dim, red light had a maximum absorbance change at 480 nm when bleached with blue-gree light. 8. There was no evidence in the latter two experiments of photointerconversion of pigments with absorbance maxima at 480 and 540 nm. Rather, the maximum absorption of the bleaching products seemed to occur at wave-lengths shorter than 420 nm. 9. Since latch-up induction occurs at wave-lengths longer than 580 nm, it may depend on the 540 pigment or on an undetected red absorbing pigment. 10. A photolabile pigment at 480 nm correlated most closely with termination of the stable inward current associated with latch-up.
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Wulff VJ, Stieve H, Fahy JL. Dark adaptation and sodium pump activity in Limulus lateral eye retinular cells. Vision Res 1975; 15:759-65. [PMID: 1154654 DOI: 10.1016/0042-6989(75)90252-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Muijser H, Leutscher-Hazelhoff JT, Stavenga DG, Kuiper JW. Photopigment conversions expressed in receptor potential and membrane resistance of blowfly visual sense cells. Nature 1975; 254:520-2. [PMID: 1121323 DOI: 10.1038/254520a0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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42
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Gwilliam G, Millecchia R. Barnacle photoreceptors: Their physiology and role in the control of behavior. Prog Neurobiol 1975. [DOI: 10.1016/0301-0082(75)90002-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
The responses of bipolar cells in the retina of the turtle have been studied by intracellular recording. Two types of bipolar cell have been identified: one gave graded depolarizing and the other graded hyperpolarizing responses to small circles of light (100 mum diameter). The responses of both types of cell were similar in the following respects.1. Both were extremely sensitive to dim light; the amplitude of response to a small circle of light increased with light intensity more steeply than the cone response.2. Enlarging the diameter of a spot added an antagonistic effect which decreased response amplitude. This decrease in response amplitude was more apparent at dim than at bright light. Stimulating only distant areas of retina with an annulus produced a response of polarity opposite to that normally produced by a central spot. However, the responses of bipolar cells did not appear to be due to a simple summation of opposite polarity signals contributed from central and peripheral parts of their receptive fields.3. When small spots or annuli of light were turned off there frequently occurred an overshooting OFF transient. The occurrence of OFF transients depended on the duration of the stimulus. Cones recorded under similar conditions produced an OFF depolarization. The size of cone OFF depolarizations increased with increasing duration of the preceding light; following approximately 3 sec of illumination their maximum amplitude was roughly 1/10 the amplitude of the preceding hyperpolarization. The size of OFF responses in both cone and bipolar cells was increased when horizontal cells were hyperpolarized by light. It is concluded that bipolar cells produce large responses for very small cone responses, and, as a consequence, a small depolarization in cones following illumination produces large OFF transients in bipolar cells. Furthermore, the responses of bipolar cells do not appear to represent a simple summation of opposite polarity input from receptor and horizontal cells.
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Junge D, Stephens CL. Cyclic variation of potassium conductance in a burst-generating neurone in Aplysia. J Physiol 1973; 235:155-81. [PMID: 4778133 PMCID: PMC1350737 DOI: 10.1113/jphysiol.1973.sp010382] [Citation(s) in RCA: 109] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
1. The hyperpolarization between bursts in the R 15 cell of Aplysia is accompanied by an increase in membrane slope conductance.2. The post-burst hyperpolarization can be observed with ouabain, lithium, or potassium-free solution if artificial inward current is applied. The hyperpolarization can be observed with dinitrophenol or cooling to 10 degrees C, with no injected current. Thus, the hyperpolarization apparently is not due to the cyclic activity of an electrogenic pump.3. A reversal potential for the post-burst hyperpolarization can be demonstrated by passage of inward current during the inter-burst period. The reversal of direction of the potential depends on recent occurrence of a burst.4. The reversal potential varies with external potassium concentration, but not with chloride or sodium.5. The post-burst hyperpolarization is not blocked by external tetraethylammonium at a concentration which greatly prolongs the action potentials.6. During the onset of spike blockage by, and recovery from, calcium-free+tetrodotoxin saline, the bursts of action potentials appear to be driven by endogenous waves of membrane potential.7. The hyperpolarizing phase of the waves in calcium-free+tetrodotoxin medium is accompanied by an increased slope conductance.8. A reversal potential can be demonstrated for the hyperpolarization following a wave in calcium-free+tetrodotoxin medium by applying inward current during the interwave period.9. The waves in calcium-free+tetrodotoxin medium are blocked by ouabain but can be reinstated by artificial hyperpolarization.10. The post-burst hyperpolarization and the post-wave hyperpolarization appear to result from a periodic increase in membrane conductance, primarily to potassium ions.
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Hillman P, Dodge FA, Hochstein S, Knight BW, Minke B. Rapid dark recovery of the invertebrate early receptor potential. J Gen Physiol 1973; 62:77-86. [PMID: 4713724 PMCID: PMC2226102 DOI: 10.1085/jgp.62.1.77] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The recovery in the dark of the early receptor potential, as a direct manifestation of the state of the visual pigments, has been studied by intracellular recording in the ventral photoreceptors of Limulus and lateral photoreceptors of Balanus. The recovery is exponential with 1/e time constants of about 80 ms at 24 degrees C for both preparations and 1800 ms at 4 degrees C for Balanus. The 24 degrees C rate extrapolates to total recovery of the pigment within 2 s. The later part of the dark adaptation of the late receptor potential, which may take from seconds to minutes in these preparations, appears thus to be unrelated to the state of the pigment.
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Hochstein S, Minke B, Hillman P. Antagonistic components of the late receptor potential in the barnacle photoreceptor arising from different stages of the pigment process. J Gen Physiol 1973; 62:105-28. [PMID: 4767023 PMCID: PMC2226106 DOI: 10.1085/jgp.62.1.105] [Citation(s) in RCA: 82] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The late receptor potential (LRP) recorded in barnacle photoreceptor cells exhibits, at high light levels, a strong dependence on the color of the stimulus and of the preceding adaptation. Most strikingly, red illumination of a cell previously adapted to blue light results in a depolarization which may last for up to 30 min after the light goes off, while blue illumination of a cell previously adapted to red light cuts short this extended depolarization or prevents its induction by a closely following red light. Comparison of the action spectra for the stimulus-coincident LRP and for the extended depolarization and its curtailment with those previously measured for the early receptor potential (ERP) confirms that these phenomena derive from the same bi-stable pigment as the ERP. The stimulus-coincident response and the extended depolarization appear to arise from substantial activation of the stable 532 nm state of the pigment, while activation of the stable 495 state depresses or prevents the extended depolarization and probably also depresses the stimulus-coincident response. Since either process can precede the other, with mutually antagonistic effects, one is not simply the reversal of the other; they must be based on separate mechanisms. Furthermore, comparison with ERP kinetics shows that both processes involve mechanisms additional to the pigment changes, as seen in the ERP. A model is proposed and discussed for the LRP phenomena and their dependences on wavelength, intensity, and duration of illumination based on excitor-inhibitor interactions.
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Christoffersen GR. Steady state contribution of the Na, K-pump to the membrane potential in identified neurons of a terrestrial snail, Helix pomatia. ACTA PHYSIOLOGICA SCANDINAVICA 1972; 86:498-514. [PMID: 4344877 DOI: 10.1111/j.1748-1716.1972.tb05352.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Abstract
1. The membrane of the moth muscle fibre was tested for resting permeability to various ions: it is not permeable to Mg(2+) or Ca(2+); it is slightly permeable to Na(+) and NH(4) (+); it is appreciably permeable to Cl(-), but Cl(-) is passively distributed; it is apparently permeable to H(+) but effects of HCO(3) (-) are not ruled out; and it is primarily permeable to K(+).2. Measurement of the internal K(+) activity showed that E(K) is less negative than the resting potential.3. In the presence of DNP, or under anoxia, the membrane potential approaches, E(K); there is a small concomitant decrease in effective membrane resistance.4. An increase in external Ca(2+) concentration is accompanied by increased effective membrane resistance and an increase in amplitude of the negative resting potential.5. Cooling the membrane (below room temperature) decreased the amplitude of the resting potential by 4-16 mV per 10 degrees C, and was accompanied by a large increase in effective membrane resistance.6. The experimental results most readily fit the hypothesis that the resting potential of the moth muscle fibre, although the membrane is highly permeable to K(+), Cl(-) and apparently to H(+), is primarily maintained by an electrogenic transport process which generates an ionic current across the membrane. The possibility that the concentration gradient of H(+) ions is metabolically maintained at a level sufficient to explain the resting potential was considered to be unlikely but could not be directly excluded.
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Millecchia R, Gwilliam GF. Photoreception in a barnacle: electrophysiology of the shadow reflex pathway in Balanus cariosus. Science 1972; 177:438-41. [PMID: 4339616 DOI: 10.1126/science.177.4047.438] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The photoreceptors in the median ocellus of the rock barnacle depolarize when illuminated. This depolarization spreads passively to the axon terminals in the supraesophageal ganglion. A small number of cells in the supraesophageal ganglion hyperpolarize when the median ocellus is illuminated and depolarize when it is shadowed. Nerve impulses are superimposed on the slow depolarization of the ganglion cells. Impulse activity in response to shadowing the median ocellus is recorded in a few fibers of the circumesophageal connectives. Picrotoxin blocks this shadow-induced activity. A model of the shadow reflex pathway is presented.
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