Dendritic morphology of a class of interstitial and normally placed amacrine cells revealed by intracellular Lucifer yellow injection in carp retina.
The dendritic morphology of a class of interstitial amacrine (ISA) and normally placed amacrine cells was investigated in carp retina. We first identified their fluorescent nuclei after preloading with 4,6-diamidino-2-phenylindole (DAPI) in living or aldehyde-fixed retinal wholemounts and then injected them iontophoretically with Lucifer Yellow (LY) under microscopic control. Although DAPI appeared to be accumulated nonspecifically by amacrine and ganglion cells, ISA cell nuclei were discriminated by focusing between the amacrine and ganglion cell layers. The fusiform cell bodies of LY-injected cells were located in the middle of the inner plexiform layer (IPL), and the 4-5 stout primary dendrites were monostratified in sublamina b of the IPL and decorated with spines and long thin processes. The average spatial properties of these cells were approximately: density, 6.0 cells/mm2; intersomatic distance, 400 microns; dendritic field size, 0.27 mm2; dendritic coverage, 1.6. The dendritic interconnections were made of tip-to-tip or tip-to-side contacts between dendrites and between a dendrite and thin process, forming many closed loops. The ISA cells belong to a morphological type Fnb. A class of normally placed amacrine cells with dendritic morphology similar to that of the ISA cells was also found by LY injection in wholemounts. These cells belong to a morphological type Fna, with dendrites monostratified in sublamina a of the IPL in a 0.35-mm2 dendritic field. The ISA (Fnb) and Fna cells appear to represent a matched pair of cell types that are similar in structure but complementary in function.
Teranishi
T
T
Department of Neurophysiology, University of Kanazawa School of Medicine, Japan.
Negishi
K
K
D000818:Animals; D001369:Axons; D002347:Carps / Q000502:physiology*; D003712:Dendrites; D007211:Indoles; D007267:Injections; D007546:Isoquinolines; D008856:Microscopy, Fluorescence; D012160:Retina / Q000166:cytology*; D012165:Retinal Ganglion Cells / Q000166:cytology
D007211:Indoles; D007546:Isoquinolines; C007293:DAPI; C017475:lucifer yellow