Purchase this article with an account.
N. Brecha, H. E. Vuong, I. Raymond; Somatostatin-Containing Amacrine Cells Directly Modulate Dopaminergic Amacrine Cells. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1207.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To identify the relationships of somatostatin (SRIF) and dopaminergic (DA) amacrine cells. DA amacrine cells have multiple influences on visual processing, and affect light/dark adaptation, circadian rhythm generation, and non-image forming circuits.
Retinas from light-adapted C57Bl/6J mice were fixed with 4% paraformaldehyde and processed for immunohistochemistry with specific antibodies to SRIF, tyrosine hydroxylase (TH: the rate-limiting dopamine synthesizing enzyme), and the SRIF receptor subtype, sst2A. The immunostaining patterns were evaluated in cryostat vertical retinal sections and whole mounts. Confocal images were collected in z-stacks containing 5 -10 optical sections (z=0.5-1 µm). Images were evaluated as both single images and as z-stacks.
Consistent with previous studies, varicose SRIF immunoreactive fibers ramify in lamina 1, 3, and 5 of the IPL and a few fibers enter the INL and OPL. SRIF somata are in the proximal layer of the INL and the GCL. TH immunostained processes ramify principally in lamina 1 and a few varicose immunostained processes are in lamina 3 of the IPL, occasionally crossing the INL to ramify in the OPL. The SRIF receptor, sst2A showed robust labeling of rod bipolar cells, and medium to large diameter amacrine cells located in the INL adjacent to the IPL and their processes in lamina 1 of the IPL. Double labeling studies revealed that SRIF and TH fibers are in apposition in laminae 1 and 3; medium to large SRIF varicosities are distributed to primary and secondary TH dendrites, and they contact TH somata. Thin varicose SRIF processes are also associated with the thinnest TH processes. Finally, there is co-localization of sst2A and TH immunoreactivity.
These studies illustrate a close relationship between SRIF and TH processes, which form extensive contacts in the IPL. These findings suggest that SRIF cells acting via sst2A influence DA amacrine cells. SRIF may influence dopamine synthesis or secretion, and thereby modulating dopamine actions in the retina.
This PDF is available to Subscribers Only