The specimens of retina along the horizontal meridian were cut together with the choroid and sclera to protect the retina from planar shrinkage (Tsukamoto et al., 1992); therefore, no shrinkage correction was undertaken. Several previous studies reported that the area with highest rod density was located along the superior vertical meridian in both macaque retina (177 103 rods/mm2; Packer et al., 1989) and human retina (158-189 103 rods/mm2; Curcio and Allen, 1990); however, the peak rod density along the temporal horizontal meridian was as high as 160 103 rods/mm2 (Mariani et al., 1984) or 120 103 rods/mm2 (Adams et al., 1974; Packer et al., 1989). is thought to provide a spatial framework for the interstitial diffusion and local uptake of the neurotransmitter (glutamate) that spills over from ribbon synapses. All five OFF bipolar cell types Rabbit Polyclonal to B3GALT4 formed ribbon-synaptic contacts to both parasol and midget ganglion cells. DB2 and 3a, DB1 and 3b, and FMB predominantly, moderately, and negligibly contacted parasol ganglion cells, respectively. FMB almost exclusively contacted midget ganglion cells, to which DB1 provided dominant output (58%), and DB2, 3a, and 3b provided between 3% and 10% of their output. Consequently, the cone signal sampling routes of a midget ganglion cell consisted of two substructures: the narrow (mainly 2-3 cones) FMB pathway and the wide (mainly 10 cones) DB pathway, where connection strength was four-fold greater in the FMB than DB pathway. The narrow and strong FMB pathway may confer the highest spatial resolution and sporadically may include blue cone signals. with 3% uranyl acetate in 80% methanol. The metal ions contained in these solutions provided some degree of density contrast to visualize subcellular components. Blocks were embedded in Araldite resin and cut in serial sections. Sections were mounted on 120 formvar-coated single-slot grids and stained with 3% uranyl acetate in 80% methanol and Reynolds’ lead citrate. These final stains provided sufficient image contrast to discriminate fine cytological features. Electron micrographs of the FTI 277 section series were acquired at both 400 and 3000 using a JEM 1220 FTI 277 electron microscope (Jeol Ltd, Tokyo, Japan) at the Joint-Use Research Facilities of Hyogo College of Medicine. Twenty-four overlapping negative images were acquired from each individual section at 3000 to capture a 90 m 187 m area covering the outer plexiform layer (OPL) to ganglion cell layer in a 4 6 montage. These images were enlarged four-fold; thus, the final magnification of prints used for image analysis was 12000 . Examination area The examination area was located 3.00C3.25 mm temporal to the foveal center and its center was approximately 15 from the foveal center. The densities of rod spherules, cone pedicles, and ganglion cells in this region were 172 103 spherules/mm2, 12.6 103 pedicles/mm2, and 11.3 103 cells/mm2. The cone pedicles were approximately 45 m far from the cone cell bodies in planar distance via Henle’s fibers. Inner and outer segments of the cones protruded perpendicularly upward from the cell bodies to the retinal surface. The density of cone cell bodies was approximately equal to that of cone pedicles in this eccentricity. The spherule to pedicle ratio was 13.6: 1 and the pedicle to ganglion ratio was 1.1: 1. The specimens of retina along the horizontal meridian were cut together with the choroid and sclera to protect the retina from planar shrinkage (Tsukamoto et al., FTI 277 1992); therefore, no shrinkage correction was undertaken. Several previous studies reported that the area with highest rod density was located along the superior vertical meridian in both macaque retina (177 103 rods/mm2; Packer et al., 1989) and human retina (158-189 103 rods/mm2; Curcio and Allen, 1990); however, the peak rod density along the temporal horizontal meridian was as high as 160 103 rods/mm2 (Mariani et al., 1984) or 120 103 rods/mm2 (Adams et al., 1974; Packer et al., 1989). Thus, the retinal locus we examined was regarded as the peak rod density area along the horizontal meridian. A similar area at 3 mm eccentricity in the temporal retina of has been investigated by W?ssle et al. (1989, 1990). They showed that the cone to ganglion ratio was approximately 1 : 1, which is almost equal to 1.1 : 1 of our sample. This cone to ganglion ratio is far less than necessary for foveal circuitry, where one cone requires more than two ganglion cells, ON and OFF midget ganglion cells. Thus, our present examination area is characterized by high-rod density and the features of peripheral circuits. Data analysis Classification of short- and middle/long- wavelength sensitive cones Short-wavelength-sensitive (S-) cones can be identified by the innervation.