238 



1. lODOACETATE AND lODOACETAMIDE 





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Fig. 1-25. Illustrations of the effects of iodoacetate on retinal histology. 



1. Cone cells in Macaca mulatta 5 weeks after the last injection of a 2-week period 

 (20-40 mg/kg iodoacetate). A: Cone cells normal in central region of fovea; B: cones 

 abnormal and rods disappeared in parafovea about 1-mm distance from central area; 

 C: cone cells more extensively damaged 2 mm from central area in parafovea; D: inner 

 segment of cone cells almost completely vanished about 4 mm from central area. 

 (From Noell, 1952.) 



IT. Retinas of chicks; iodoacetate at 40 mg/kg intravenously. 1: Normal retina; 

 2: 2 hr after iodoacetate; pycnosis in the ganglionic and inner and outer granular 

 layers; 3: 24 hr after iodoacetate, some glycogen still present in accessory cones (arrow) 

 (periodic acid-Schiff hematoxylin stain); 4: 4 days after iodoacetate, rods and cones 

 no longer distinguishable, profound disorganization of granular layers, and migration 

 of pigment cells; 5: 6 days after iodoacetate, only pigment cell layer recognizable. 

 (From Rabinovitch et al., 1954.) 



Malate and pyruvate can partially protect rats against the lethal effects 

 of iodoacetate, but giving malate with iodoacetate produces a much more 

 severe retinal degeneration than with iodoacetate alone, malate by itself 

 having no effect (Graymore and Tansley, 1959 a). The inhibition of gly- 

 colysis in the retina in vivo by iodoacetate does not appear to be altered 

 by giving malate (Graymore and Tansley, 1959 b). The mechanism of this 



