Synaptic organization of serotonin-like immunoreactive amacrine cells in the larval tiger salamander retina

Watt, Carl B.; Wilson, E.A.

doi:10.1016/0306-4522(90)90342-2

Cited by 12 publications

(10 citation statements)

References 33 publications

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“…The synaptic connections of SLI amacrine cells in this species have been established (Gabriel et al, 1993). As seen in the retinas of other nonmammalian species (Millar & Morgan, 1989;Hurd & Eldred, 1993;Watt & Wilson, 1990), SLI amacrine cells in Bufo marinus form synapses with other amacrine cells, bipolar cells, and presumed ganglion cells. Recent observations suggest that all large and some small SLI amacrine cells in this species are able to synthesize serotonin, whereas other small SLI amacrine cells may only accumulate serotonin .…”

Section: Synaptic Circuits Of Serotonin-synthesizing and Serotonin-acmentioning

confidence: 82%

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Synaptic circuitry of serotonin-synthesizing and serotonin-accumulating amacrine cells in the retina of the cane toad, Bufo marinus

1995

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The synaptic connections of amacrine cells synthesizing or accumulating serotonin in the retina of the cane toad, Bufo marinus, were studied by using preembedding double-labeling electron-microscopic immunocytochemistry. The binding sites of an anti-serotonin antibody were revealed by the diaminobenzidine reaction, whilst a colloidal gold-conjugated secondary antibody was used to detect an antibody to phenylalanine hydroxylase. Since the latter antibody recognizes tryptophan 5-hydroxylase, one of the synthesizing enzymes for serotonin, as well as tyrosine hydroxylase, the rate-limiting enzyme for catecholamine synthesis, the double labeling of the present study enabled us to identify three groups of labeled profiles at the ultrastructural level. The profiles of serotonin-synthesizing amacrine cells contained both diaminobenzidine reaction product and colloidal gold particles, whilst those of serotonin-accumulating and dopaminergic amacrine cells contained only diaminobenzidine reaction product or colloidal gold particles, respectively. The synapses of serotoninsynthesizing or serotonin-accumulating amacrine cells were distributed all through the inner plexiform layer of the retina. The profiles of serotonin-synthesizing amacrine cells predominantly received synapses from, and made synapses onto, unlabeled amacrine cell dendrites. They also received synapses from, and made synapses onto, bipolar cell terminals. They also made synapses onto presumed ganglion cell dendrites. However, the profiles of serotonin-accumulating cells made synapses only with unlabeled amacrine cell processes. There were close contacts between the profiles of serotonin-synthesizing and serotonin-accumulating amacrine cells. No synaptic relationships were observed between dopaminergic and serotonin-synthesizing or serotonin-accumulating amacrine cells. These observations indicate that serotonin-synthesizing amacrine cells and serotonin-accumulating amacrine cells in the retina of Bufo marinus are involved in different microcircuits in visual information processing.

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Section: Synaptic Circuits Of Serotonin-synthesizing and Serotonin-acmentioning

confidence: 82%

“…The synaptic connections of SLI amacrine cells have been investigated in the retinas of chick (Millar & Morgan, 1989); turtle (Hurd & Eldred, 1993); tiger salamander (Watt & Wilson 1990); and Xenopus laevis and Bufo marinus (Gdbriel et al, 1993). Labeled amacrine cells frequently form synapses with unlabeled amacrine cells.…”

Section: Introductionmentioning

confidence: 99%

Synaptic circuitry of serotonin-synthesizing and serotonin-accumulating amacrine cells in the retina of the cane toad, Bufo marinus

1995

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“…However, the convention has been to divide the IPL into five or ten equal bins for analysis. A five-bin analysis makes it possible to compare our data to that of previous studies (for example, Watt & Wilson, 1990, see also Fig. 6), while some interesting features emerge from a 55045 split analysis of the IPL.…”

Section: Distribution Of Gabaϩ Amacrine Synapses In the Iplmentioning

confidence: 80%

“…However, the neurochemical synaptic organization of salamander retina has received less attention, except for some older and more recent EM immunocytochemical studies (e.g. Watt et al, 1985;Watt & Wilson 1990;Watt & Glazebrook, 1993;Yang & Wang, 1999;Yang et al, 2003). Salamander retina has been a particularly difficult preparation for preembedding immunocytochemistry.…”

Section: Discussionmentioning

confidence: 99%

“…Comparison labels include: a1, a3, b1, b203, g1 and g2 GABA A -receptor subunits (Zhang et al, 2003). The following antisera colocalize with GABA immunoreactivty in salamander amacrine cells and the distribution of their processes in the IPL are represented: serotonin (5HT synapses; Watt & Wilson, 1990), enkephalin (ENK synapses; Watt et al, 1985), choline acetyltransferase (ChAT terminals; Deng et al, 2001), substance P (SP terminals; , somatostatin (SRIF terminals;, and glucagon (GLUC terminals; Yang et al, 1991). Marc & Liu (2000).…”

Section: Gabaϩ Output To Bipolar Cellsmentioning

confidence: 99%

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Synaptic organization of GABAergic amacrine cells in the salamander retina

Zhang

Wang²,

Yang³

2004

Vis Neurosci

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The synaptic organization of GABA-immunoreactive (GABA-IR) amacrine cells in the inner plexiform layer (IPL) of salamander retina was studied with the use of postembedding immuno-electron microscopy. A total of 457 GABA-IR amacrine synapses, with identified postsynaptic elements, were analyzed on photomontages of electron micrographs covering 3,618 microm2 of the IPL. GABA-IR amacrine synapses were distributed throughout the IPL, with a small peak at the proximal margin of sublamina a. The majority of the output targets (81%) were GABA(-) neurons. Most of the contacts were simple synapses with one postsynaptic element identified as a process of an amacrine cell (55%), bipolar cell (19%) or ganglion cell (26%), and serial synapses were very rare. Of the 89 postsynaptic bipolar terminals, 63% participated in a reciprocal feedback synapse with the same presynaptic GABA-IR amacrine profile. There appeared to be no preference between GABA-IR amacrine contacts with rod- or cone-dominated bipolar cells (9.1% vs. 8.9%) or in the total number of amacrine synapses in sublaminas a and b (52% vs. 47%). The preponderance of amacrine cell input to bipolar cells in the OFF layer was derived from GABA-IR cells. These findings provide ultrastructural support to the existing physiological studies regarding the functional roles of the GABAergic amacrine cells in this species. Our results have added to the data base demonstrating that, in contrast to mammals, GABA-IR amacrine cells in amphibians and other nonmammals contact other amacrine cells more frequently, suggesting greater involvement of GABAergic amacrine cells in modulating lateral inhibitory pathways.

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