Identification of sensory neurons supplying receptors in lingual muscles of the rat: histochemical and retrograde labeling study with horseradish peroxidase.

Sensory innervation of lingual musculature was studied in young adult Wistar rats using retrograde labeling by horseradish peroxidase (HRP) and combined silver impregnation and acetylcholinesterase (AchE) methods. Intra-lingual injection of HRP resulted in labeling of neuronal somata in the trigeminal, superior vagal, and second cervical spinal (C2) ganglia. When HRP was directly applied to the proximal stump of severed hypoglossal nerve, labeling occurred only in the cervical and superior vagal ganglia. Morphometric analysis revealed that the labeled neurons were of the small-sized category in all ganglia. However, in the trigeminal and C2 ganglia, labeling occurred also among the medium-sized neurons. Combined silver and AchE preparations from lingual muscles revealed the absence of typical muscle spindles. Instead, there were free and spiral nerve terminals in the interstitium, and epilemmal knob-like or bouton-like endings surrounding non-encapsulated muscle fibers. These terminals showed AchE -ve reaction in contrast to the motor ones. Few ganglionic cells were scattered along the hypoglossal nerve with uniform AchE +ve reaction in their perikarya. This indicates that medium-sized neurons in the trigeminal and C2 ganglia, and probably sensory neurons along the hypoglossal nerve mediate lingual muscle sensibility perceived by atypical sensory terminals.

Ultrastructural localization of adenosine triphosphatase activity in HeLa cells at various stages of the cell cycle.

HeLa cells in a monolayer culture were synchronized to S, G2 and mitotic phases by use of excess (2.5 mM) deoxythymidine double-block technique. The localizations of Ca2++-activated adenosine triphosphatase (ATPase) at different phases of the cell cycle were studied using light- and electron-microscopic histochemical techniques, and microphotometric comparisons of the densities of reaction products. Enzyme reaction product was always localized in the endoplasmic reticulum, nuclear membrane, mitochondria and Golgi apparatus, but there were qualitative and quantitative differences related to the phases of the cell cycle. In S phase the activity was mainly concentrated in a perinuclear area of the cytoplasm whereas in G2 and mitosis the activity was scattered throughout the cell. The total activity per cell was maximal in G2, was less in S phase and least in mitosis. Activity in the mitochondria and endoplasmic reticulum was distinctly less in mitosis than in other phases of the cell cycle. The mitochondrial ATPase differed from the ATPase at other sites in ion dependence and sensitivity to oligomycin. The results suggest that there may be several distinct ATPases in proliferating cells.

Histochemical localization of adenosine triphosphatase activity in thymus: a light microscopical and ultrastructural study.

Ultrastructural localization of ATPase at high pH in the presence of Ca2+ showed that activity in thymocyte precursors was stronger than in mature thymocytes. The activity was localized in the nuclear envelope, rough endoplasmic reticulum, Golgi apparatus and mitochondria. The difference in activity was attributed to a marked decrease in ATPase-containing organelles, mainly the endoplasmic reticulum in the mature thymocytes. This appears to be related to the proliferative activity of the cells rather than to the immunological maturity of the thymocytes. A very strong activity, also localized in the same organelles, was present in the macrophages and interdigitating cells which might have a secretory function and possibly contribute to thymocyte maturation. The Ca2+-ATPase activity in the nuclear envelope-endoplasmic reticulum system suggests that these may be the sites for storage and regulation of cytoplasmic calcium.

The fate of phytohaemagglutinin-activated human lymphocytes following their peak proliferative activity.

Morphological and histochemical studies and cell counts were performed on phytohaemagglutinin-stimulated lymphocyte cultures at intervals from 1 to 17 days. Following a phase of proliferative activity lasting from the second to the sixth days, different cell types became evident in the later stages of culture. Some of the cells were large and characterised by an abundant cytoplasm containing numerous electron-dense bodies with a characteristic internal structure, a well developed Golgi apparatus, a highly irregular plasma membrane, numerous pinocytoses and intense acid phosphatase activity localised within the dense bodies. These cells resembled epithelioid cells in which phagocytic vacuoles were very infrequent. In contrast, phagocytic cells distended with phagocytosed debris were present throughout the period of culture. In later cultures many of the cells were smaller than activated lymphocytes. Intermediate sized cells were characterised by a paucity of organelles and low acid phosphatase activity, and small cells were similar to unstimulated lymphocytes but frequently contained numerous mitochondria. A few cells with a highly developed endoplasmic reticulum were observed at 3 days and also in later stages. The large cells with intense acid phosphatase activity constituted 20-30% of the total cells at 6 days but were more sparse in later stages when intermediate and small lymphocytes predominated. The total cell count on the seventeenth day was 50% of the initial cell count and the cells were almost entirely small, apparently healthy lymphocytes.

Ultrastructural localization of adenosine triphosphatase activity in lymphocytes activated in vitro by phytohaemagglutinin.

The ultrastructural localization of Ca2+, Mg2+-activated ATPase was studied in phytohaemagglutinin activated lymphocytes and in normal unstimulated lymphocytes. Cells, fixed in paraformaldehyde--glutaraldehyde, were incubated in a medium containing 3 mM ATP, 5 mM CaCl2 and 2.4 mM Pb(NO3)2 in 0.1 M tris buffer at pH 8.5, the optimum pH for histochemical demonstration of this enzyme. Reaction product was localized in the endoplasmic reticulum, nuclear membrane, Golgi apparatus and mitochondria and on the membrane surrounding large electron-dense bodies. Cytoplasmic vesicles and the plasma membrane were negative. Activity in unstimulated lymphocytes showed a similar localization but the amount of endoplasmic reticulum was much less than in activated lymphocytes. The pH of the medium was critical for the localization of the enzyme. At pH 7.5, the cytoplasmic reaction was almost completely inhibited but a dense precipitate was present on the outer surface of the plasma membrane. The reaction was stimulated by either Ca2+ or Mg2+ and was greatly decreased in the absence of these cations or in the presence of p-chloromercuribenzoate or N-ethylmaleimide. Oligomycin inhibited selectively the reaction in mitochondria but not the reaction at other sites. While the reaction in mitochondria showed complete substrate specificity, a mild reaction was obtained at the other sites with uridine diphosphate or sodium beta-glycophosphate as substrate. ATP was, however, the preferential substrate.