Identification of horizontal cells generating different spectral responses in the retina of a teleost fish (Eugerres plumieri)

Abstract

Six different types of spectral responses were recorded from horizontal cells under mesopic conditions in perfused retina, isolated from the dark-adapted mojarra (Eugerres plumieri). They were tentatively termed photopic Lr-, Lg1-, Lg2-, Lb-, and C-type, and scotopic L-type. The Lr-, Lg-, and Lb-type responses showed a maximum peak at 605, 550, and 516 nm respectively, while the C-type was composed of hyperpolarizing potentials in response to shorter wavelengths and depolarizing potentials in response to longer wavelengths (so-called R/G-type). The scotopic L-type has a peak at 516 nm in the spectral response and a slow decay phase in the waveform response. Following a brief period of diffuse illumination, it was found that the Lg1-type response is altered to the Lr-type, while both Lg2- and Lb-type responses change to the C-type. Intracellular marking with Lucifer or Procion yellow identified the cellular origins of different response types: external (He) and medial horizontal (Hm) cells for the Lr-type, internal horizontal (Hi) cells for the C-type, and rod-horizontal (Hr) cells for the scotopic L-type. Only He cells were found to possess an axon, while dye coupling was seen between axonless Hm, Hi, or Hr cells but not between He cells. The morphology of these fluorescent dye-marked cells was the same as that of the respective cells observed in Golgi-stained materials.

Origins of horizontal cell spectral responses in the retina of marine teleosts (Centropomus andMugil Sp.)

“…1A,B) as in Eugerres (Negishi et al, 1988a). However, in about 20% of the penetrations to the Centropomus retina, the sL-type response was picked up immediately below the level where the L-type was recorded.…”

“…L-type includes exclusively hyperpolarizing responses present in H1 and H2 cells in different species, regardless of the different wavelengths that evoke the maximal response. The L-type response of Eugerres HCs has been found to have an amplitude maximum at 605 nm (Lr-type) or at 550 nm (Lg1-type) depending upon the adaptational state, and the biphasic C-type includes the Lg2-and Lb-type (Negishi et al, 1988a). The biphasic C(R/G)-type in the Mugil retina may include the triphasic C(Y/RB)-type (Svaetichin et al, 1961;Mitarai, 1982), as the longest wavelength of the present spectral stimulus system was 650 nm, which did not permit showing the hyperpolarizing component of the triphasic C-type response at longer wavelengths.…”

“…The upper (H2) was LY-labeled and the lower (H3) cell was PY-labeled in both cases. The inner nuclear layer is indicated between two horizontal lines in C and E. Scales 5 50 µm; the scale in A is also for B,D, and E. Mitarai, 1982;Negishi et al, 1988a). Even for the monophasic L-type response, several subtypes have been termed, depending upon the fish species used and the wavelength at which the maximum response amplitude occurs, it being variable due to adaptational states of the retina (Mitarai et al, 1961;Weiler and Wagner, 1984;Djamgoz et al, 1985;Negishi et al, 1988a,b).…”

“…Juvenile specimens 10-15 cm in body length with an eyeball diameter of 8-10 mm were used. The isolated retina was placed, photoreceptor side up, in a specially designed chamber which allows for superfusion (Laufer, 1982;Negishi et al, 1988a). In many cases the retinas were small and were used under air-exposed, mesopic conditions.…”

Análise de células bipolares PKCa-IR e células ganglionares da retina do peixe tropical Hoplias malabaricus intoxicado com baixas doses agudas de metilmercúrio

“…A enzima PKCα foi encontrada em células bipolares na retina de diferentes vertebrados (Caminos et al, 2000), como salamandra (Umino et al, 2003), tartaruga (Zhang et al, 1992), galinha (Caminos et al, 1999), bovinos (Shin et al, 2006), ratos (Negishi et al, 1988;Greferath et al, 1990;Osborne et al, 1991Osborne et al, ,1992Zhang & Yeh, 1991;Kosaka et al, 1998;Gabriel et al, 2001), gato (Fykkolodziej et al, 2002, coelho (Usuda et al, 1991;Osborne et al, 1991Osborne et al, , 1992Koistinanho & Sagar, 1994), macaco (Grünert & Martin, 1991;Fukuda et al, 1994;Haverkamp et al, 2003), em retina humana Haverkamp et al, 2003) e inclusive na retina de peixes (Suzuki & Kaneko, 1990;Osborne et al, 1992;Vaquero et al, 1997;Job & Lagnado, 1998 …”