Comparison of the responses of Necturus retinal ganglion cells to stationary and moving stimuli

A detailed examination was made of the responses of Necturus retinal ganglion cells to stationary and moving stimuli, with the aim of assessing the degree of response specificity of on-off cell “motion detectors”. Responses to stationary and moving stimuli were recorded while changing one stimulus parameter (intensity, size or duration) in the same manner for both stationary and moving stimuli, with all other stimulus parameters fixed. Sustained-on cells were used as controls, since they are not particularly movement sensitive.No pronounced or systematic differences were observed between the ways the responses of on-off cells to stationary and moving stimuli depended on the three stimulus parameters. In no case were the differences in response dependence more pronounced for individual on-off cells than for some sustained-on cell. Therefore, Necturus on-off ganglion cells should not be considered “motion detectors”.     

Responses of the amacrine cell to optic nerve stimulation in the frog retina

Responses of the frog amacrine cell to optic nerve stimulation were examined. Amacrine cells of “on-off” and “off” type responded to optic nerve stimulation in an all or none fashion. When double stimulation was applied, the latency to test stimulus was reduced as stimulus interval was shortened (less than about 200 msec). At shorter stimulus intervals (less than several milliseconds), prolongation of the latency was observed. An assumption was proposed that the ganglion cell dendrite makes contact back onto the amacrine cell, and the reduction of latency is caused by facilitation in dendritic invasion of the impulse in the ganglion cell.     

小鼠视网膜胆碱能无长突细胞和方向选择性神经节细胞树突野发育的相关性研究

目的探讨小鼠视网膜方向选择性神经节细胞(DSGC)树突野(DF)的发育及其与胆碱能细胞阵列的关系。 方法选用中国科学院生物物理研究所实验动物中心繁殖的清洁级YFP(H)品系的转基因小鼠(种鼠来源于The Jackson实验室)共36只,0～1月龄,雌雄不限。对出生后不同发育时期(P8、P13及成年)的小鼠视网膜中ON/OFF DSGC及OFF DSGC的DF范围内包含的胆碱能细胞的数目采用单因素方差分析进行比较,当差异有统计学意义时,进一步两两比较。 结果ON/OFF DSGC作为经典的方向选择性神经节细胞,其树突具有两层树突结构,分别分布在视网膜内网状层的ON和OFF亚层中,其树突弯曲度和树突分支之间的夹角比较大,分支多向胞体方向返回呈半环状,显著的特点是同一细胞的树突不会发生交叉。P8时,D2亚类神经节细胞(即ON/OFF DSGC)DF范围中分别包含(25.6±4.8)个内核层(INL)的胆碱能无长突细胞和(28.4±5.7)个视网膜神经节细胞(GCL)的胆碱能无长突细胞(n＝7);P13时,D2亚类神经节细胞DF范围中分别包含(30.8±9.5)个INL的胆碱能无长突细胞和(35.2±10.4)个GCL的胆碱能无长突细胞(n＝10);成年时,D2亚类神经节细胞DF范围中分别包含(33.7±7.4)个INL的胆碱能无长突细胞和(32.1±5.6)个GCL的胆碱能无长突细胞(n＝9),三个时期的胆碱能无长突细胞的数目差异均无统计学意义(F＝2.16,1.55;P>0.05)。而视网膜中另外一种方向选择性神经节细胞OFF DSGC的DF范围内无长突细胞的数目从P8到P13先增多,然后从P13到成年又减少。P8时,该类细胞DF范围内位于GCL的无长突细胞数目为(20.0±2.5,n＝8)个,明显少于P13时的(32.0±7.1,n＝6)个;成年时,数目又减少到(23.7±7.5,n＝14)个。,三个时期的胆碱能无长突细胞的数目差异均无统计学意义(F＝6.19,1.55;P<0.05)。 结论小鼠视网膜ON/OFF DSGC的DF在出生后早期就已经发育成熟,并和胆碱能细胞形成稳定的联系,不再受后期双极细胞及光刺激的影响,而OFF DSGC的DF发育可能包含不同的分子和细胞机制。     

Physiological and morphological identification of amacrine cells in the retina of the larval tiger salamander

The amacrine cells in the salamander retina were identified by intracellular recording of photoresponses and staining with Procion yellow or Lucifer yellow. The characteristic amacrine cell response consists of a transient depolarization at both the onset and offset of illumination. Three morphological types of amacrine cell were recognized and correlated to different photoresponses. The small-field stratified amacrine cells respond to light stimulation with prolonged depolarizing waves. The multistratified amacrine cells exhibit sharp “on-off” depolarizing responses followed by shallow hyperpolarization. The large-field monostratified amacrine cell responses to small spots are transient depolarizations followed by slow hyperpolarizations while their responses to diffuse and peripheral illumination are transient depolarizations.     

AMPA receptor kinetics limit retinal amacrine cell excitatory synaptic responses

Amacrine cells that respond transiently to maintained illumination are thought to mediate transient inhibitory input to ganglion cells. The excitation of these transient amacrine cells is thought to be limited by inhibitory feedback to bipolar cells. We investigated the possibility that desensitizing AMPA and/or kainate (KA) receptors on amacrine cells might also limit the duration of amacrine cell excitation. To determine how these receptors might affect amacrine cell input and output, we made whole-cell recordings from amacrine and ganglion cells in the salamander retinal slice. The specific AMPA receptor antagonist GYKI-53655 blocked non-NMDA receptor-mediated amacrine cell excitatory postsynaptic currents (EPSCs) and kainate puff-elicited currents, indicating that AMPA, and not KA, receptors mediated the responses. Cyclothiazide, an agent that reduces AMPA receptor desensitization, increased the amplitude and duration of amacrine cell EPSCs. To measure the output of transient amacrine cells, we recorded glycinergic inhibitory postsynaptic currents (IPSCs) from ganglion cells, and found that these were also enhanced by cyclothiazide. Thus, prolongation of amacrine cell AMPA receptor activation enhanced amacrine cell output. Current responses elicited by puffing glycine onto ganglion cell dendrites were not affected by cyclothiazide, indicating that the enhancement of glycinergic IPSCs was not due to a direct effect on glycine receptors. These data suggest that rapid AMPA receptor desensitization and/or deactivation limits glycinergic amacrine cell excitation and the resulting inhibitory synaptic output.     

Expression of brain-derived neurotrophic factor in cholinergic and dopaminergic amacrine cells in the rat retina and the effects of constant light rearing

Brain-derived neurotrophic factor (BDNF) regulates many aspects of neuronal development, including survival, axonal and dendritic growth and synapse formation. Despite recent advances in our understanding of the functional significance of BDNF in retinal development, the retinal cell types expressing BDNF remains poorly defined. The goal of the present study was to determine the localization of BDNF in the mammalian retina, with special focus on the subtypes of amacrine cells, and to characterize, at the cellular level, the effects of constant light exposure during early postnatal period on retinal expression of BDNF. Retinas from 3-week-old rats reared in a normal light cycle or constant light were subjected to double immunofluorescence staining using antibodies to BDNF and retinal cell markers. BDNF immunoreactivity was localized to ganglion cells, cholinergic amacrine cells and dopaminergic amacrine cells, but not to AII amacrine cells regardless of rearing conditions. Approximately 75% of BDNF-positive cells in the inner nuclear layer were cholinergic amacrine cells in animals reared in a normal lighting condition. While BDNF immunoreactivity in ganglion cells and cholinergic amacrine cells was significantly increased by constant light rearing, which in dopaminergic amacrine cells was apparently unaltered. The overall structure of the retina and the density of ganglion cells, cholinergic amacrine cells and AII amacrine cells were unaffected by rearing conditions, whereas the density of dopaminergic amacrine cells was significantly increased by constant light rearing. The present results indicate that cholinergic amacrine cells are the primary source of BDNF in the inner nuclear layer of the rat retina and provide the first evidence that cholinergic amacrine cells may be involved in the visual activity-dependent regulation of retinal development through the production of BDNF. The present data also suggest that the production or survival of dopaminergic amacrine cells is regulated by early visual experience.     

On and off pathways through amacrine cells in mammalian retina: the synaptic connections of "starburst" amacrine cells

The neural architecture of on and off pathways in mammalian retina is described, including the development of ideas leading to an understanding of the bisublaminar organization of the inner plexiform layer of the retina which supports these two pathways. The complexities of bipolar cell contributions are contrasted with the relative simplicity of ganglion cell organization with regard to bisublaminar architecture, and a key role is described for internuncial amacrine cells as specific targets for bipolar cells. Two very different kinds of amacrine cell are considered and compared, both of which mediate bipolar input to ganglion cells. These are the rod (type II) amacrine cell, and the more recently discovered "starburst" amacrine cell, which is apparently cholinergic in function. As different as the wide-field starburst amacrine cells are from the narrow-field rod amacrine cells, they share important features. Both are interposed between bipolar and ganglion cells, and both have segregated regions of presynaptic boutons. They differ, however, in that rod amacrines may perform more specific functions related to receptive field center organization, while the functional role of starburst amacrines may be unrelated to receptive field properties of ganglion cells. The mirror-symmetry of type a and type b (off and on) starburst amacrine cells is described together with their synaptic circuitry. In contrast to the rod amacrine cell the output of starburst amacrines is exclusively to ganglion cells. Others have proposed a dual function for acetylcholine (ACh) in the retina. A unifying hypothesis is briefly sketched here which relates the pharmacology of ACh and the dendritic stratification of starburst amacrine cells to the form and function of ganglion cells. It is proposed that the amount of generalized synaptic excitation received from ACh/starburst amacrine cells by a particular type of ganglion cell is largely a function of co-stratification of the ganglion cell's dendrites with the distal boutons of starburst amacrine cells.     

The effects of serotonin agonists and antagonists on the response properties of complex ganglion cells in the rabbit's retina

Selective agonists and antagonists were employed to determine the role of indoleaminergic amacrine cells in the generation of the light-evoked responses and spontaneous activity of direction and orientation selective cells. Perfusion with 5-HT2 antagonists reduced the spontaneous activity and both the leading and trailing edge responses of ON/OFF direction selective cells. 5-HT1a agonists had a similar effect on this class of cell, namely, a reduction of light-evoked and spontaneous activity. Results from ON-center and OFF-center orientation selective cells were consistent with those obtained from direction selective cells in that no disruption of direction or orientation selectivity was observed during perfusion of these drugs. These data suggest that the indoleaminergic cells are not directly involved in the generation of the trigger features of complex ganglion cells, but may be facilitating synaptic transmission in the inner retina. This function is discussed relative to the connectivity of the rod bipolar cells and the putative indoleaminergic amacrine cells. The similarity of the effects of 5-HT1a agonists and 5-HT2 antagonists supports the hypothesis, developed during our prior studies of brisk ganglion cells, that these two receptor classes mediate antagonistic processes in the target neurons.     

Cholecystokinin in the cat retina. Action of exogenous CCK8 and localization of cholecystokinin-like immunoreactivity

The effects of applying cholecystokinin (CCK8) iontophoretically onto cat retinal ganglion cells were studied in the optically intact eye of the cat. CCK8 suppressed both the maintained and the light evoked discharge of brisk ganglion cells, irrespective of their being on- or off-center, brisk-transient, or brisk-sustained and independent of the state of light adaptation. The inhibitory action of CCK8 in the cat retina is opposite from its excitatory action in other parts of the brain. Using an antiserum to cholecystokinin, immunoreactivity was localized in horizontal cells and amacrine cells of the cat retina. Inconsistently immunoreactivity also was found in ganglion cells and fibers.     

Regional distribution of nitrergic neurons in the inner retina of the chicken

Using both NADPH diaphorase and anti-nNOS antibodies, we have identified-from retinal flatmounts-neuronal types in the inner retina of the chicken that are likely to be nitrergic. The two methods gave similar results and yielded a total of 15 types of neurons, comprising 9 amacrine cells, 5 ganglion cells, and 1 centrifugal midbrain neuron. Six of these 15 cell types are ubiquitously distributed, comprising 3 amacrine cells, 2 displaced ganglion cells, and a presumed orthotopic ganglion cell. The remaining nine cell types are regionally restricted within the retina. As previously reported, efferent fibers of midbrain neurons and their postsynaptic partners, the unusual axon-bearing target amacrine cells, are entirely confined to the ventral retina. Also confined to the ventral retina, though with somewhat different distributions, are the "bullwhip" amacrine cells thought to be involved in eye growth, an orthotopic ganglion cell, and two types of large axon-bearing amacrine cells whose dendrites and axons lie in stratum 1 of the inner plexiform layer (IPL). Intracellular fills of these two cell types showed that only a minority of otherwise morphologically indistinguishable neurons are nitrergic. Two amacrine cells that branch throughout the IPL are confined to an equatorial band, and one small-field orthotopic ganglion cell that branches in the proximal IPL is entirely dorsal. These findings suggest that the retina uses different processing on different regions of the visual image, though the benefit of this is presently obscure.     

Cross-talk between ON and OFF channels in the salamander retina: indirect bipolar cell inputs to ON-OFF ganglion cells

It has been widely accepted that ON and OFF channels in the visual system are segregated with little cross-communication, except for the mammalian rod bipolar cell-AII amacrine cell-ganglion cell pathway. Here, we show that in the tiger salamander retina the light responses of a subpopulation of ON-OFF ganglion cells are mediated by crossing the ON and OFF bipolar cell pathways. Although the majority of ON-OFF ganglion cells (type I cells) receive direct excitatory inputs from depolarizing and hyperpolarizing bipolar cells (DBCs and HBCs), about 5% (type II cells) receive indirect excitatory inputs from DBCs and 20% (type III cells) receive indirect excitatory inputs from HBCs. These indirect bipolar cell inputs are likely to be mediated by a subpopulation of amacrine cells that exhibit transient hyperpolarizing light responses (AC(H)s) and make GABAergic/glycinergic synapses on DBC or HBC axon terminals. GABA and glycine receptor antagonists enhanced the ON and OFF excitatory cation current (DeltaI(C)) in type I ganglion cells, but completely suppressed the ON DeltaI(C) mediated by DBCs in type II cells and the OFF DeltaI(C) mediated by HBCs in types III cells. Dendrites of type I cells ramify in both sublamina A and B, type II cells exclusively in sublamina A, and type III cells exclusively in sublamina B of the inner plexiform layer. These results demonstrate that indirect, amacrine cell-mediated bipolar cell-ganglion cell synaptic pathways exist in a non-mammalian retina, and that bidirectional cross-talk between ON and OFF channels is present in the vertebrate retina.     

Distribution of GABA immunoreactivity in the cat retina: a light- and electron-microscopic study

The distribution of GABA-like immunoreactivity in the cat retina was studied through the use of preembedding immunocytochemistry for light microscopy and by postembedding immunogold techniques for electron microscopy. Staining was observed in both inner and outer plexiform layers. Approximately 30% of the somata in the amacrine portion of the inner nuclear layer were immunoreactive and included amacrine and interplexiform cells. Horizontal cells and a subpopulation of cone bipolar cells were also stained. In the ganglion cell layer, staining was observed in both small- and medium-sized neurons. GABA-labeled amacrine cells were presynaptic to somata of amacrine cells and to dendrites of amacrine, bipolar, and ganglion cells. Bipolar cells were a major target, receiving more than 60% of all labeled synapses in the inner plexiform layer. Many of these contacts were reciprocal synapses. These findings support a major role for GABA-labeled amacrines in providing feedback inhibition to bipolar cells in the inner retina.     

Receptive fields and response properties of neurons in the rat visual cortex

Most receptive fields of neurons in the visual cortex (area 17) of rats could be mapped with moving and stationary stimuli. Neurons were most effectively driven by moving stimuli. They were classified s motion (37 per cent), orientation (11 per cent), or direction selective (4 per cent) and indefinite cells (41 per cent). Many cells had only a weak response to stationary stimuli: however, pure “on”, “off” or “on-off” receptive fields were found for some neurons; others were of the complex type with mixed response regions in the receptive field. Receptive field sizes were usually quite large (range of the major receptive field axes for the most common class of cells—motion selective—was 15°–50°) as expected considering the sizes of retinal ganglion and LGN cell receptive fields as found in the rat by other investigators.     

Neurotransmitter-specific identification and characterization of neurons in the all-cone retina of Anolis carolinensis, I: Gamma-aminobutyric acid.

The inhibitory amino-acid neurotransmitter, gamma-aminobutyric acid (GABA), was localized in the pure cone retina of the lizard Anolis carolinensis by autoradiographic and immunocytochemical techniques. Uptake of [3H]-GABA labeled horizontal cells, amacrine cells, numerous cells in the ganglion cell layer, both plexiform layers, and the nerve fiber layer. Label in the inner plexiform layer showed distinct lamination. The pattern of GABA immunoreactivity was similar to the pattern of [3H]-GABA uptake, although some differences, particularly in labeling of amacrine and ganglion cells, were observed. Immunocytochemistry revealed endogenous stores of GABA in a set of horizontal cells, amacrine cells, and cells in the ganglion cell layer. Both plexiform layers were labeled by the GABA antisera. Labeling in the inner plexiform layer (IPL) was highly stratified and GABA-immunoreactive strata were present in both sublaminae a and b. Six subtypes of conventionally placed GABA-immunoreactive amacrine cells and one displaced amacrine cell subtype were identified. Three of the six conventional amacrine cell subtypes were of pyriform morphology and three subtypes were of multipolar morphology. GABA-immunoreactive interstitial cells also were observed. Under certain conditions the GABA antiserum labeled the cones. Etching the resin eliminated cone labeling, suggesting that GABA in the cones is present in a labile pool, unlike GABA in horizontal or amacrine cells, or the observed labeling was not due to endogenous GABA. Cones did not demonstrate [3H]-GABA uptake.     

Neurotransmission in the frog retina: Possible physiological and histological correlations

In the frog retina, extracellular recordings of transient ganglion cells have shown that the inhibitory surround of the receptive field of these cells was mediated by gammaaminobutyric acid and acetylcholine (through the nicotinic receptors). Histoautoradiographic and immunocytochemical studies for the two respectively have shown that these neurotransmitters can act through horizontal and amacrine cells. The separation of the ON and OFF channels mediated by glutamate at the bipolar cell level may also be obtained by glycine and/or acetylcholine (through muscarinic receptors). Respective histoautoradiographic and immunocytochemical studies indicate that these neurotransmitters act at the amacrine cell level. These data are consistent with the functional separation of spatial and temporal organization of retinal information, with horizontal cells especially responsible for the spatial organization of the ganglion cell responses and amacrine cells involved in both spatial and temporal organization of the responses.     

Localization of classical neurotransmitters in interneurons of the larval tiger salamander retina

Autoradiography was used to visualize the neurons in the tiger salamander retina that exhibit high-affinity uptake of 3H-dopamine, [3H]-serotonin, [3H]-glycine, and [3H]-GABA. Both [3H]-dopamine and [3H]-serotonin were accumulated by amacrine cells and by displaced amacrine cells. [3H]-glycine was taken up by amacrine cells, displaced amacrine cells, bipolar cells, and displaced bipolar cells. [3H]-GABA was accumulated by amacrine cells and by cells in the ganglion cell layer that may be displaced amacrine or ganglion cells. [3H]-GABA was also taken up by horizontal cells, bipolar cells, and displaced bipolar cells.     

Amacrine cell contributions to red-green color opponency in central primate retina: a model study

To investigate the contributions of amacrine cells to red-green opponency, a linear computational model of the central macaque retina was developed based on a published cone mosaic. In the model, amacrine cells of ON and OFF types received input from all neighboring midget bipolar cells of the same polarity, but OFF amacrine cells had a bias toward bipolar cells whose center responses were mediated by middle wavelength sensitive cones. This bias might arise due to activity dependent plasticity because there are midget bipolar cells driven by short wavelength sensitive cones in the OFF pathway. The model midget ganglion cells received inputs from neighboring amacrine cells of both types. As in physiological experiments, the model ganglion cells showed spatially opponent responses to achromatic stimuli, but they responded to cone isolating stimuli as though center and surround were each driven by a single cone type. Without amacrine cell input, long and middle wavelength sensitive cones contributed to both the centers and surrounds of model ganglion cell receptive fields. According to the model, the summed amacrine cell input was red-green opponent even though inputs to individual amacrine cells were unselective. A key prediction is that GABA and glycine depolarize two of the four types of central midget ganglion cells; this may reflect lower levels of the potassium chloride co-transporter in their dendrites.     

SP-8-CPT-cAMP对神经节细胞和无长突细胞间示踪剂藕连的影响

目的：研究SP-8-CPT-cAMP对兔眼视网膜神经节细胞和无长突细胞间示踪剂藕连的影响。方法：兔眼视网膜组织培养，并用SP-8-CPT-cAMP(环腺苷酸的类似物)处理。采用细胞显微注射方法将神经生物素注射入视网膜组织单个活体关闭性α亚型（OFF-α)神经节细胞中，终止注射后，用4％甲醛固定，1：600Cy3-链亲合素反应，并用共焦显微镜测定在藕连的神经节细胞和无长突细胞中通过缝隙连接扩散的示踪剂的量。结果：在被注射的神经节细胞(G0)树突区及树突区之外可见未注射的神经节细胞(G1)被染色，此外还可见数十个胞体较小、位于内核层的明亮的(A1)和暗的(A2)无长突细胞被染色。经SP-8-CPT-cAMP处理后，藕连的G1，A1，A2的神经生物素示踪剂浓度明显高于未用药组(注射后1h)。结论：OFF-α神经节细胞和无长突细胞间存在缝隙连接，神经节细胞间也存在直接缝隙连接。SP-8-CPT-cAMP增加了神经节细胞藕连网缝隙连接的通透性。眼科学报；2003；19：126-129     

Effects of the destruction of starburst-cholinergic amacrine cells by the toxin AF64A on rabbit retinal directional selectivity

The effects of intraocular injections of ethylcholine mustard aziridinium ion (AF64A), an irreversible inhibitor of choline uptake, on the rabbit retina were assessed electrophysiologically, pharmacologically, anatomically, and behaviorally. Survival times from 1 day to 30 days were investigated. After 24 h, the shortest time tested, the directional selectivity of On-Off responding ganglion cells having the characteristic morphology of On-Off directionally selective directionally selective (DS) ganglion cells, as revealed by intracellular dye injection, was significantly reduced, both by an apparent decrease of preferred direction responses and an increase in responses to null-direction movement. No toxin-mediated changes in the dendritic trees of these cells were noted. Cells in AF64A-affected retinas having the DS morphology did not respond significantly to GABAergic or cholinergic agents such as picrotoxin and eserine, but did respond to nicotine. Recordings from a small random sample of other ganglion cell classes in the same retinas yielded no obvious changes in response properties. The direct effects on starburst (cholinergic) amacrine cells, which were identified by intraocular injection of the fluorescent dye DAPI with the AF64A, were investigated by intracellular injections of Lucifer yellow, and by immunohistochemical staining with antibodies to choline acetyltransferase (ChAT). Although starburst amacrine cell somas survived the AF64A treatment for at least several days, the dendrites could not be visualized by fluorescent dye injection in affected retinas due to dye leakage of the injected fluorescent dye from either the soma or proximal dendritic region. ChAT staining revealed a sequence in which ChAT-positive cells were undetectable first in the inner nuclear layer, and then in the ganglion cell layer. Cholinergic amacrine cells in the central retina were also affected before those in the periphery. The electrophysiological changes observed typically preceded the loss of ChAT activity. Behavioral tests for optokinetic nystagmus responses also revealed a lack of such responses in the affected eyes.     

Stratification of α ganglion cells and ON/OFF directionally selective ganglion cells in the rabbit retina

The correlation between cholinergic sensitivity and the level of stratification for ganglion cells was examined in the rabbit retina. As examples, we have used ON or OFF alpha ganglion cells and ON/OFF directionally selective (DS) ganglion cells. Nicotine, a cholinergic agonist, depolarized ON/OFF DS ganglion cells and greatly enhanced their firing rates but it had modest excitatory effects on ON or OFF alpha ganglion cells. As previously reported, we conclude that DS ganglion cells are the most sensitive to cholinergic drugs. Confocal imaging showed that ON/OFF DS ganglion cells ramify precisely at the level of the cholinergic amacrine cell dendrites, and co-fasciculate with the cholinergic matrix of starburst amacrine cells. However, neither ON or OFF alpha ganglion cells have more than a chance association with the cholinergic matrix. Z -axis reconstruction showed that OFF alpha ganglion cells stratify just below the cholinergic band in sublamina a while ON alpha ganglion cells stratify just below cholinergic b . The latter is at the same level as the terminals of calbindin bipolar cells. Thus, the calbindin bipolar cell appears to be a prime candidate to provide the bipolar cell input to ON alpha ganglion cells in the rabbit retina. We conclude that the precise level of stratification is correlated with the strength of cholinergic input. Alpha ganglion cells receive a weak cholinergic input and they are narrowly stratified just below the cholinergic bands.