LOCALIZATION AND BIOCHEMICAL-CHARACTERIZATION OF ACID-PHOSPHATASE ISOFORMS IN THE OLFACTORY SYSTEM OF ADULT-RATS

Localization of acid phosphatases was studied with the use of beta-gly cerophosphate and p-nitrophenyl phosphate as substrates in the brain w ith special emphasis on the olfactory system of adult rat at light and electron microscopic level. With the use of P-glycerophosphate, a sel ective substrate for the lysosomal acid phosphatase. lead-containing r eaction product was found in primary and secondary lysosomes of neuron s, glial cells and perivascular macrophages as well as in the cytoplas m of olfactory sensory axons. Incubation with p-nitrophenyl phosphate as substrate additionally revealed a cytoplasmic isoform of acid phosp hatase, which could not be inhibited by tartrate or fluoride and was p redominantly located in dendrites. Acid phosphatase isoforms were bioc hemically characterized in samples prepared separately from the olfact ory mucosa, olfactory nerve layer, olfactory bulb and its dendrodendri tic synaptosomes isolated by subcellular fractionation. In the olfacto ry mucosa and olfactory nerve layer the lysosomal type (high molecular weight form) was the most prominent acid phosphatase form, whereas th e isoform located in dendrites corresponded to the tartrate-resistant extralysosomal, cytosolic type (low molecular weight form). The functi onal significance of different isoforms of acid phosphatase in the olf actory sensory axons and dendritic elements is discussed. Copyright (C ) 1996 IBRO.