Tridimensional architecture of the golgi apparatus in the atrial muscle cell of the rat

Abstract

The tridimensional structure of the Golgi apparatus of atrial muscle cells has been studied in thin and thick sections with low- and high-voltage electron microscopes. Cardiac tissue was inpregnated with osmium, stained to demonstrate phosphate activity (i.e., nicotinamide adenine dinucleotide phosphatase or NADPase; thiamine pyrophosphatase or TPPase; cytidine monophosphatase or CMPase) or postfixed and stained with potassium ferrocyanide-reduced osmium. At low power, in thick (3-10 micron) sections, the cisosmiophilic element and the NADPase- and the TPPase-positive saccules each appeared as a continuous irregular ribbon that formed, at the two poles of the nucleus, two conical masses connected to each other by beltlike bands encircling the nucleus. At higher magnifications, the continuous Golgi apparatus showed saccular regions along its length connected by short intersaccular tubular regions. In the saccular regions, the following five superimposed elements formed a stack: (1) the cis-osmiophilic network of anastomosed tubules; (2) a chromophobic, dilated saccule perforated with numerous pores; (3) a thin NADPase-positive saccule showing few pores; (4) a thin TPPase-positive saccule perforated with numerous minute pores; and (5) a CMPase-positive transelement that showed saccular and tubular regions and was often partly separated from the overlying saccule. In the intersaccular tubular regions, membranous tubules connected and bridged saccules of two adjacent saccular regions. Secretory granules usually appeared in this region as dilations of the tubules connected to all elements of the Golgi stack except the cis-osmiophilic element.

<b>Integrative method for three-dimensional imaging of the entire Golgi apparatus by combining thiamine pyrophosphatase cytochemistry and array tomography using backscattered electron-mode scanning electron micr</b><b>oscopy </b>

“…Thus, in the present study, we developed an alternative approach involving a combination of TPPase cytochemistry and array tomography using SEM for labeling and visualizing the entire Golgi apparatus, which clearly demonstrated differences in the 3D structure of this organelle between cerebellar Purkinje cells and pituitary gonadotropes. Osmium impregnation (6,7,11,27,33,34,36) TIFF, and then were transferred again into the Amira software and converted to grayscale. Based on these data, 3D surface images of the Golgi apparatus, nucleus, and cytoplasm were rendered by the Amira isosurface tool.…”

“…Further, using this technique we previously compared the 3D ultrastructure on the cis-and trans-most cisterns between various cell types (20), and found a peculiar but rational organization of the spherical Golgi apparatus in rat pituitary gonadotropes (47). Several techniques have been developed for specific labeling of the Golgi apparatus in cells/tissues, including osmium impregnation (6,7,11,27,33,34) and thiamine pyrophosphatase (TPPase) cytochemistry (6,11,27,(32)(33)(34). Recently, we developed a novel method combining osmium impregnation with osmium maceration, and succeeded in visualizing the osmiophilic cis-Golgi cisterns with surrounding 3D structures by backscattered electron (BSE)-mode SEM (16).…”

“…In contrast to cerebellar Purkinje cells, pituitary gonadotropes on ultrathin sections were immunocytochemically identified prior to SEM observation, as the anterior pituitary is comprised of at least five and TPPase cytochemistry (6,11,27,(31)(32)(33)(34) are well established methods for labelling the cis-and trans-Golgi cisterns, respectively, in various cell types. An advantage of TPPase cytochemistry over osmium impregnation is its highly versatile staining over a wide variety of cells; reduced osmium was deposited in the lumen of the cis-Golgi cisterns in pituitary gonadotropes (16,17), but not in cerebellar Purkinje cells (data not shown), while lead precipitates after TPPase cytochemistry were observed in the trans-Golgi cisterns both of Purkinje cells and gonadotropes, as demonstrated in the present study.…”

Architecture of the Mammalian Golgi

“…1). However, in some cells or after strong stimuli, CVs can also be seen in one or more trans-Golgi cisternae (Rambourg et al 1984;Rambourg 1997;Slot et al 1997;Arvan and Castle 1998). These, and other, observations have raised the question as to whether exit from the Golgi might also occur from earlier cisternae and not be exclusively confined to the TGN (for further discussion see below) (Rambourg and Clermont 1990).…”

Sodium channels near end‐plates and nuclei of snake skeletal muscle.

“…Tassin, Paintrand, Berger & Bornens (1985) found the Golgi apparatus to be associated with nuclei during myotube formation in culture. In atrial cardiac muscle, Rambourg, Segretain & Clermont (1984) found that the Golgi stacks were intimately associated with nuclei, being concentrated at both poles and forming a ribbon-like structure around the nucleus.…”