Enzyme histochemistry of embryonic nasal mucosa

Abstract

The prenatal development of rodent nasal mucous membrane has been examined histochemically (lactate dehydrogenase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, alkaline phosphatase, PAS and PAS with diastase digestion). Localization and intensity of the enzyme systems studied were distinctly different in respiratory and olfactory areas. These differences were demonstrable by at least the second half of gestation in the animals studied. Findings i n Jacobson's organs were parallel to those in olfactory areas. Each of the pathways of carbohydrate metabolism examined was present in respiratory epithelium. However, intensity was less, appeared later and was more variable in intracellular localization than that found in olfactory areas. Based on enzyme staining olfactory epithelium seemed metabolically more active than respiratory mucosa. Apical portions of olfactory epithelium stained most intensely for oxidative enzyme systems, particularly the glucose-6-phosphate dehydrogenase system. These areas of high activity were thought to represent apices of supporting cells rather than receptor cells. This localization of a pentose phosphate shunt enzyme system was related speculatively to ion transport in these cells. Alkaline phosphatase was relatively slight in respiratory areas during the ages studied. The basal portions of olfactory epithelium stained positively for alkaline phosphatase. Since hydrolytic enzymes have been thought to be important in the mechanism of olfaction, its demonstration in these tissues suggests that this portion of the olfactory mechanism is present by midgestation in the rodents studied.

Prenatal development of the mammalian vomeronasal organ

“…High activity of glycolytic enzymes has been shown to take place in VNO neuroepithelium during embryonic life (Shapiro, 1970). Likewise, fetal rats have been shown to have increased 2-deoxyglucose (2-DG) uptake in the AOB (Pedersen et al, 1984).…”

“…8b), while other neuron perikarya appear at diverse degrees of development, showing abundant ribosomes and a varying number of other organelles. LDH staining appears intense and SDH moderate (Shapiro, 1970). Gradually the entire thickness of the neuroepithelium becomes well stained for these oxidative enzymes, but staining is consistently more intense at the adluminal surface, while alkaline phosphatase shows an intense staining at basal location (Shapiro, 1970).…”

“…LDH staining appears intense and SDH moderate (Shapiro, 1970). Gradually the entire thickness of the neuroepithelium becomes well stained for these oxidative enzymes, but staining is consistently more intense at the adluminal surface, while alkaline phosphatase shows an intense staining at basal location (Shapiro, 1970). Vomeronasal neuroblasts express protein gene product 9.5 (Johnson et al, 1994) and manganese superoxide dismutase immunoreactivity increases (Kulkarni-Narla et al, 1997).…”

“…Active cell proliferation is taking place in the neuroepithelium, with abundant mitotic figures, mainly in the apical layer. At the end of this period, a prominent staining for lactate dehydrogenase (LDH) has been shown, as well as an intense staining for glucose-6-phosphate dehydrogenase (G6PD) at the apical region, while succinate dehydrogenase (SDH) reaction was slight and alkaline phosphatase staining appears at the basal region (Shapiro, 1970). CC1 monoclonal antibodies, which react with an N-acetyl-galactosamine-containing glycolipid, appear as a faint punctate staining in receptor cell perikarya of central regions of the VNO, CC2 staining appears in a similar manner, and P-Path reacts weakly with the vomeronasal cells (Schwarting et al, 1992).…”

The Anatomical Record is Smell‐Bound

“…In the 1950s, 1960s, and 1970s, functional studies appeared in the Journal. Among the scientific reports are papers that dealt with regeneration of olfactory epithelium and nerves, using frogs as the study subjects (Smith, ), capillary blood flow in the olfactory bulb of salamanders (Roofe, ), enzyme immunohistochemistry in nasal mucosa of embryonic rats and mice (Shapiro, ), and differentiation of rat olfactory receptor cells in organ culture (Farbman, ). Morphologically bent papers on the olfactory system returned to the pages of The Anatomical Record in the 1980s.…”