Postmortem metabolic capacity of photoreceptor cells in human and rat retinas

Retinas of postmortem human donor eyes retained the high-affinity mechanism for uptake of 3H-taurine, the capacity to synthesize rhodopsin from 14C-amino acids, and the ability to incorporate inorganic 32P-phosphate into rhodopsin with exposure to light for 4 to 4 1/2 hr. These processes declined at a rate of about 16% to 19% per hour between 2 and 4 1/2 hr after death. Parallel studies with rats maintained after death at room temperature (22 degrees C) showed that all three processes declined linearly at rates of 8% to 12% per hour. In rats maintained after death at body temperature (37 degrees C) or on ice (4 degrees C), the rates of decline in rhodopsin synthesis were respectively 20% to 22% and 7% to 9% per hour, whereas the rates of decline of rhodopsin phosphorylation at these temperatures were, respectively, 20% to 22% and 3% to 5% per hour. Retinas from rats maintained after death in light or dark at room temperature showed no differences in their capacity to synthesize or phosphorylate rhodopsin from la 7% to 9% per hour, whereas the rates of decline of rhodopsin phosphorylation at these temperatures were, respectively, 20% to 22% and 3% to 5% per hour. Retinas from rats maintained after death in light or dark at room temperature showed no differences in their capacity to synthesize or phosphorylate rhodopsin from la 7% to 9% per hour, whereas the rates of decline of rhodopsin phosphorylation at these temperatures were, respectively, 20% to 22% and 3% to 5% per hour. Retinas from rats maintained after death in light or dark at room temperature showed no differences in their capacity to synthesize or phosphorylate rhodopsin from labeled precursors. These findings in human and rat eyes show that photoreceptor cells can perform energy-requiring processes for several hours after death.