Age-related changes in the dendrites of olfactory receptor neurons in the male silkmoth Antheraea peryni (Insecta, Lepidoptera: Saturniidae)

A study was conducted to evaluate the changes that occur with aging at the dendrite level of the olfactory receptor neuron in the male silkmoth Antheraea pernyi Using calcein AM/ethidium homodimer-1 solutions, we found increased numbers of dendrites with damaged membrane with aging. Correspondingly there was an overall decrease in the electrophysiological activity as evidenced by the decreased number of cells discharging nerve impulse in response to female pheromone. It was also seen that the number of membrane swellings increased with age. In young animals aged 1-4 days, swellings showed intact membrane, and in older animals aged 5-15 days, they showed damaged membranes. With TUNEL assay that detects fragmented DNA in dying cells, an increased number of dendrites showing cytoplasmic labelling with age was found. The presence of fragmented DNA within aged dendrites was also confirmed in polyacrylamide gels after DNA extraction and PCR amplification. When tested for reversal of phosphatidylserine from the inner leaflet to the outer leaflet of plasma membrane no reactivity was seen. It appears that changes that occur during aging of dendrites may reflect some of the recognized symptoms of both apoptosis and necrosis. (C) 1998 Academic Press.