PII component of the toad electroretinogram

1992 ◽  
Vol 68 (1) ◽  
pp. 333-341 ◽  
Author(s):  
B. J. Katz ◽  
Z. Xu ◽  
J. Zheng ◽  
B. Oakley
Keyword(s):  
Excitatory Amino Acid ◽  
Cell Activity ◽  
Plexiform Layer ◽  
Müller Cell ◽  
Light Responses ◽  
M Wave ◽  
Cell Responses ◽  
Ion Sensitive Microelectrodes ◽  
Muller Cell ◽  
Dc Component

1. The PII component of the electroretinogram (ERG) is comprised of the b-wave and the DC component and is thought to reflect bipolar cell activity. Although the b-wave is generated in large part by a K+/Muller cell mechanism, the origin of the DC component is unclear. In this paper we detail our investigation of the origin of the DC component. We hypothesize that the DC component is generated by a K+/Muller cell mechanism identical to that involved in b-wave generation. 2. We studied the ERG in the dark-adapted, isolated retina preparation of the toad, Bu fo marinus. We used K+ ion-sensitive microelectrodes (K+ISM), as well as conventional intra- and extracellular microelectrodes, to record [K+]o changes, the vitreal ERG, and Muller cell responses. 3. We used the excitatory amino acid receptor agonist N-methyl-DL-aspartate (NMDLA) to inhibit light responses of third-order neurons and thereby eliminate most of the ERG M-wave. In the absence of the M-wave, the ERG consisted of PII and PIII. We then superfused the retina with a solution containing both kynurenic acid (KYN) and 2-amino-4-phosphonobutyric acid (APB), which together inhibit all retinal responses proximal to the photoreceptors. In the presence of KYN and APB, the ERG consisted only of PIII. Using digital subtraction, we reconstructed PII. To our knowledge, this is the first report of the isolation of a PII component in the ERG of a nonmammalian species. 4. Using K+ISMs, we recorded the distal K+ changes in the outer plexiform layer (OPL).(ABSTRACT TRUNCATED AT 250 WORDS)

M-wave of the toad electroretinogram

1991 ◽  
Vol 66 (6) ◽  
pp. 1927-1940 ◽  
Author(s):  
B. J. Katz ◽  
R. Wen ◽  
J. B. Zheng ◽  
Z. A. Xu ◽  
B. Oakley
Keyword(s):  
Plexiform Layer ◽  
Müller Cell ◽  
Inner Plexiform Layer ◽  
Excitatory Effect ◽  
Inner Retina ◽  
M Wave ◽  
Threshold Response ◽  
Slow Piii ◽  
Muller Cell ◽  
Toad Bufo

1. In the retina, two distinct, light-evoked releases of K+ have been described. One takes place in the outer plexiform layer (OPL) and is termed the "distal K+ increase." The other takes place in the inner plexiform layer (IPL) and is termed the "proximal K+ increase." Although the distal K+ increase generates the electroretinogram (ERG) b-wave, the contribution of the much larger proximal K+ increase to the ERG is less well understood. In this paper we detail our investigation of the proximal K+ increase and its contribution to the ERG. We describe an ERG component, the M-wave, which had not heretofore been observed in the diffuse-flash, vitreal ERG. 2. We studied the proximal K+ increase and the ERG M-wave in the isolated retina preparation of the toad, Bufo marinus. We used K(+)-sensitive microelectrodes, as well as conventional intra- and extracellular microelectrodes, to record K+ changes, the local (or intraretinal) ERG, the vitreal ERG, and Muller cell responses. 3. As in earlier studies of the amphibian and cat M-wave, we readily observed an M-wave in the intraretinal, or local, ERG (LERG). The M-wave we studied had characteristics similar to those of M-waves that were previously described. Specifically, we found that the M-wave was generated by a Muller cell response to the proximal K+ increase and that both the proximal K+ increase and the LERG M-wave were spatially tuned. 4. We used the aspartate receptor agonist, N-methyl-DL-aspartate (NMA), to reveal that an M-wave is present in the vitreal ERG. Researchers who previously investigated the M-wave were unable to identify an M-wave in the vitreal ERG. We found that the toad ERG M-wave was a small, positive potential that was partially obscured by the much larger b-wave and slow PIII components. 5. We observed that picrotoxin (PTX) had an excitatory effect on inner retina, as evidenced by an enhanced proximal K+ increase and an enhanced M-wave. This result indicates that it is likely that GABAergic inhibition in inner retina plays an important role in retinal processing in the toad. 6. At threshold, we found that the ERG consisted mainly of an M-wave, indicating that the amphibian threshold ERG is driven by proximal retina. This result is analogous to previous observations of the threshold ERG in cat. However, in cat, the M-wave and threshold response have been described as distinct ERG components.(ABSTRACT TRUNCATED AT 400 WORDS)

Relationship between Muller cell responses, a local transretinal potential, and potassium flux

1977 ◽  
Vol 40 (2) ◽  
pp. 244-259 ◽  
Author(s):  
C. J. Karowski ◽  
L. M. Proenza
Keyword(s):  
Müller Cells ◽  
Müller Cell ◽  
Extracellular Potassium ◽  
Muller Cells ◽  
Light Onset ◽  
M Wave ◽  
Cell Responses ◽  
Stimulus Parameters ◽  
Muller Cell ◽  
Cell Depolarization

1. In the Necturus retina, light-evoked field potentials, Muller (glial) cell responses, and extracellular potassium ion concentration ([K+]0) were recorded and found to exhibit the three-way correlation characteristic of these variables elsewhere in the nervous system. 2. Muller cell responses to a flashed spot or annulus consist primarily of slow depolarizations at both light onset and offset. The responses are maximum to 0.5-mm-diameter spots and decrease with larger diameters. Responses to stimulus intensity and flicker were also used to characterize Muller cell behavior. 3. In response to long-duration stimuli, the initial Muller cell depolarization is followed by a very slow hyperpolarization, which is likely the origin of slow PIII. 4. A new extracellular potential is described, the M-wave, the basic properties of which suggest that it is generated by Muller cells. Moreover, the M-wave and Muller cells show remarkably similar behavior to a wide variety of stimulus parameters. 5. In the proximal retina, [K+]0 increases at both light onset and offset with a time course similar to that of Muller cell depolarizing responses. This K+ increase also behaves similarly to the Muller cell depolarization in response to changes in stimulus parameters. 6. It is concluded that light stimulation leads to an increase in [K+]0 in the proximal retina and that this increase depolarizes Muller cells whose associated currents, in turn, generate the M-wave.

scholarly journals Neurons, potassium, and glia in proximal retina of Necturus.

1980 ◽  
Vol 75 (2) ◽  
pp. 141-162 ◽  
Author(s):  
C J Karwoski ◽  
L M Proenza
Keyword(s):  
Time Course ◽  
Primary Source ◽  
Amacrine Cells ◽  
Müller Cell ◽  
Wave Form ◽  
Cell Responses ◽  
Decay Times ◽  
Low Pass ◽  
Muller Cell ◽  
Time Courses

Light-evoked K+ flux and intracellular Müller (glial) cell and on/off-neuron responses were recorded from the proximal retina of Necturus in eyecups from which the vitreous was not drained. On/off-responses, probably arising from amacrine cells, showed an initial transient and a sustained component that always exhibited surround antagonism. Müller cell responses were small but otherwise similar to those recorded in eyecups drained of vitreous. The proximal K+ increase and Müller cell responses had identical decay times, and on some occasions the latency and rise time of the K+ increase nearly matched Müller cell responses, indicating that the recorded K+ responses were not always appreciably degraded by electrode "dead space." The spatiotemporal distribution of the K+ increase showed that both diffusion and active reuptake play important roles in K+ clearance. The relationship between on/off-neuron responses and the K+ increase was modelled by assuming that (a) K+ release is positively related to the instantaneous amplitude of the neural response, and (b) K+ accumulating in extracellular space is cleared via mechanisms with approximately exponential time-courses. These two processes were approximated by low-pass filtering the on/off-neuron responses, resulting in modelled responses that match the wave form and time-course of the K+ increase and behave quantitatively like the K+ increase to changes in stimulus intensity and diameter. Thus, on/off-neurons are probably a primary source of the proximal light-evoked K+ increase that depolarizes glial cells to generate the M-wave.

Effects of synaptic blocking agents on the depolarizing responses of turtle cones evoked by surround illumination

1990 ◽  
Vol 5 (6) ◽  
pp. 571-583 ◽  
Author(s):  
Wallace B. Thoreson ◽  
Dwight A. Burkhardt
Keyword(s):  
Receptive Field ◽  
Excitatory Amino Acid ◽  
Horizontal Cell ◽  
Current Injection ◽  
Horizontal Cells ◽  
Light Responses ◽  
Calcium Dependent ◽  
Cell Responses ◽  
Blocking Agents ◽  
Amino Acid Antagonists

AbstractThe effects of synaptic blocking agents on the antagonistic surround of the receptive field of cone photoreceptors were studied intracellular recording in the retina of hte turtle (Pseudemys scripta elegans) Illumination of a cone's receptive-field surround typically evoked a hybriid depolarizing response composed of two componests: (1) the graded synaptic feedback depolarization and (2) the prolonged depolarization a distinctive, intrinsic response of the cone. The locus of action of synaptic blocking agents was analyzed by comparing their effects on the light-evoked response of horizontal cells, the hybrid cone depolarization evoked by surround illumination, and the pure prolonged depolarization evoked by intracellular current injection.The excitatory amino-acid antagonists, d-O-phosphoserine (DOS) and kynurenic acid (KynA), suppressed the light responses of horizontal cells and eliminated the surround-evoked, hybrid cone depolarization without affecting the prolonged depolarization evoked by current injection. Cobalt at 5–10 mM suppressed horizontal cell responses and thereby eliminated surround-evoked cone depolarizations. Cobalt (5–10 mM) also blocked the current-evoked prolonged depolarization, suggesting that the intrinsic cone mechanisms responsible for the prolonged depolarization are likely to be calcium-dependent.Various GABA agonists and antagonists were found to have no effect on the surround-evoked depolarizations of cones. In contrast, a very low concentration of cobalt (0.5 mM) selectively suppressed the light-evoked feedback depolarization of cones without affecting horizontal cell responses or the current-evoked prolonged depolarization. Cobalt at 0.5 mM thus blocks the light-evoked action of the cone feedback synapse while sparing feedforward synaptic transmission from cones to horizontal cells. The implications of the present work for the possible neurotransmitters used at these synapses is discussed.

scholarly journals Adaptive Müller cell responses to microglial activation mediate neuroprotection and coordinate inflammation in the retina

2011 ◽  
Vol 8 (1) ◽  
pp. 173 ◽  
Author(s):  
Minhua Wang ◽  
Wenxin Ma ◽  
Lian Zhao ◽  
Robert N Fariss ◽  
Wai T Wong
Keyword(s):  
Microglial Activation ◽  
Müller Cell ◽  
Cell Responses ◽  
Muller Cell

First Responders: Dynamics of Pre-Gliotic Müller Cell Responses in The Isolated Adult Rat Retina

2014 ◽  
Vol 40 (12) ◽  
pp. 1245-1260 ◽  
Author(s):  
Linnéa Taylor ◽  
Karin Arnér ◽  
Fredrik Ghosh
Keyword(s):  
First Responders ◽  
Müller Cell ◽  
Rat Retina ◽  
Adult Rat ◽  
Cell Responses ◽  
Muller Cell

Contributions to the electroretinogram of currents originating in proximal retina

1988 ◽  
Vol 1 (3) ◽  
pp. 307-315 ◽  
Author(s):  
Laura J. Frishman ◽  
Paul A. Sieving ◽  
Roy H. Steinberg
Keyword(s):  
Plexiform Layer ◽  
Inner Plexiform Layer ◽  
Pattern Erg ◽  
Light Onset ◽  
M Wave ◽  
Extracellular Recordings ◽  
Scotopic Threshold Response ◽  
Threshold Response ◽  
Dc Component ◽  
Near Threshold

AbstractWe have investigated responses in proximal retina of the cat that contribute to two kinds of electroretinogram (ERG) recordings: (1) the pattern ERG, a light-adapted response and (2) the threshold and near threshold ERG, a dark-adapted response (Sieving et al., 1986a, 1986b; Sieving & Steinberg, 1985). In intraretinal, extracellular recordings, two negative-going responses were identified that are maximal around the inner plexiform layer, and distinct from PII, which is maximal in distal retina: under light-adapted conditions, a spatially tuned response at light onset and light offset, the “M-wave” (previously described in cold-blooded animals by Karwoski & Proenza (1977, 1980)), and under dark-adapted conditions, the scotopic threshold response, or “STR,” a response at light onset. The results under dark-adapted conditions are examined in more detail here.The STR is a very sensitive response whose threshold is 1.5–2.0 log units below that of the dc-component of PII and therefore well below the threshold of the a-, b-, and c-waves. It saturates about 2.4 log units below rod saturation. The STR contributes a negative-going potential to the dark-adapted ERG that is dominant near threshold; while PII (dc-component and b-wave) contributes a positive-going potential that is dominant at higher intensities (Sieving et al., 1986b). Investigation of the mechanism of the proximal retinal responses that contribute to the ERG supports a K+-Müller cell hypothesis of their origin.

Cellular Organization in Retinal Transplants Using Cell Suspensions or Fragments of Embryonic Retinal Tissue

1993 ◽  
Vol 2 (5) ◽  
pp. 411-418 ◽  
Author(s):  
Bengt Juliusson ◽  
Anders Bergström ◽  
Theo Van Veen ◽  
Berndt Ehinger
Keyword(s):  
Cell Suspension ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell Suspensions ◽  
Müller Cell ◽  
Immunocytochemical Staining ◽  
Inner Plexiform Layer ◽  
Cellular Organization ◽  
Muller Cell ◽  
Retinal Transplants

We have investigated the cellular organization in two different types of retinal transplants using cell type-specific monoclonal antibodies. Both fragments and cell suspensions of E17-E19 Sprague–Dawley rat retina were transplanted to a subretinal site in congenic adult rat hosts. After a survival time of 28 days, the transplants were stained by immunocytochemistry with antibodies against rhodopsin, which stained rods; with antibodies against HPC-1, which stained amacrine cells and outer and inner plexiform layers; and with antibodies against vimentin, which stained Müller cell fibers and horizontal cells. In the host retina, the distribution of immunocytochemical staining was similar, irrespective of transplantation technique. In the transplants, the antirhodopsin staining showed that fragment transplants developed photoreceptors in rosettes, whereas in cell suspension transplants, this staining showed a scattered distribution of photoreceptors. The HPC-1 staining showed that regions corresponding to the inner nuclear layer surrounded both types of transplants and made large invaginations into them. In one case, using the cell suspension technique, fibres were found to run from the inner plexiform layer of the transplant to the outer plexiform layer of the host. The vimentin staining revealed a disorganized array of Müller cell fibres in both types of transplants, but with some concentration to the regions corresponding to the inner plexiform layer.

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