Freeze-Etching of Intercellular Junctions of Mouse Liver

Kreutziger, G. Oscar

doi:10.1017/s0424820100100913

Cited by 71 publications

(16 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Orthogonal arrays have been observed over the entire surface of glial cells, but they are most prevalent on "end feet" and adjacent to an extended space (i.e., perivascular submeningeal or sinusoidal) or to a fluid system (i.e., blood, lymph, or cerebrospinal fluid) (13). Similarly, these arrays on epithelial membranes are found near periglandular spaces and adjacent to basal lamina or fluid spaces (5)(6)(7)(8)(9). It has been suggested, based on their location, that these structures are associated with or play a role in the regulation of the concentration of certain ionic species in the interstitial fluids (13).…”

Section: Discussionmentioning

confidence: 99%

Orthogonal arrays in normal and injured respiratory airway epithelium.

Gordon¹

1985

The Journal of Cell Biology

View full text Add to dashboard Cite

Orthogonal arrays are found on plasma membranes of glial cells, in the central nervous system, on muscle plasma membranes at neuromuscular junctions, and on a variety of epithelial cells. These structures have been correlated with ion flux. With the aid of freeze fracture technique, orthogonal particle arrays were found on plasma membranes on airway epithelial cells of rats and hamsters. They have been found in abundance at the base of secretory cells throughout normal airway epithelium. These structures were found to increase in number during regeneration in response to injury and they were found in great numbers on plasma membranes of all airway cells in response to acute and chronic NO2 exposure. The lateral and basal plasma membranes of the respiratory epithelium are a new source for studying orthogonal arrays. The normal number and distribution of these arrays can be perturbed in response to mechanical and chemical injury.Orthogonal particle assemblies (rectangular arrays) are closely packed 6-nm intramembrane particles arranged in a square lattice. These assemblies have been found on the P-face of freeze-fractured plasma membranes of a variety of cells (1-11). Mammalian astrocytes, in particular, can be identified in freeze fractures by the abundance of these structures on their plasma membrane (12).The biochemical nature of these particles and their function in the membrane have not been determined. It has been speculated that these structures are associated with ion flux, at least in astrocytes (13).In this report we describe a rich source for these orthogonal structures in respiratory epithelium of rats and hamsters. We also describe conditions that increase their abundance, thereby perhaps providing a mechanism whereby these structures could be biochemically characterized and their function determined. MATERIALS AND METHODS20 male Syrian Golden hamsters weighing -60 g for the chronic study and 125 g for the acute study were divided into two groups. One group of eight animals was exposed to NO2:2 for 6 h, 2 for 24 h, 2 for 48 h, and the last 2 remained as controls breathing room air. The second group of 12 animals was exposed to NO2:2 for 1 mo, 2 for 5 mo, 2 for 9 mo, and the remaining six animals were used as unexposed age controls, two animals corresponding to each exposure period (1, 5, and 9 mo).Rationale for NOz Exposure: NO2 is a noxious gas that has been known to cause emphysematous lesions in rats (14) and hamsters (15). We have been using continuous NO2 exposure in hamsters as an animal model for the study of the development and progression of lesions caused by this agent in bronchioles and alveolar epithelium. During the studies in which we examined barrier function disruption of respiratory epithelium we made the observations reported in this manuscript. NO2 Exposure Techniques:The exposure groups were treated with NO2 at concentrations of 30 ppm for 22 h per day, 7 d per wk. 30 ppm was chosen because it was low enough not to cause death and yet high enough to cause a consistent lesi...

show abstract

Section: Discussionmentioning

confidence: 99%

Orthogonal arrays in normal and injured respiratory airway epithelium.

Gordon¹

1985

The Journal of Cell Biology

View full text Add to dashboard Cite

show abstract

“…Square arrays apparently similar to those described in skeletal muscle (22, 45-47, 49, 52) and cardiac muscle (36) are observed on cells that do not conduct propagated action potentials. They have been found in the lateral plasma membranes of intestinal epithelial cells (54), on brain astrocytes (14,31), in hepatocyte plasma membranes (30), and in the basal and lateral surfaces of the light cells of kidney collecting tubule (29). Staehelin's (54) early speculations that the square arrays might present a special third type of gap junction have subsequently been rendered inoperable because the arrays appear on cell surfaces separated by large spaces and thick intervening basement membranes (49).…”

Section: Metabolic Properties Vs Contractile Propertiesmentioning

confidence: 99%

Studies of excitable membranes. II. A comparison of specializations at neuromuscular junctions and nonjunctional sarcolemmas of mammalian fast and slow twitch muscle fibers.

Ellisman¹,

Rash²,

Staehelin³

et al. 1976

The Journal of Cell Biology

250

116

View full text Add to dashboard Cite

A BSTR ACTMammalian fast and slow twitch skeletal muscles are compared by freeze-fracture, thick and thin sectioning, and histochemical techniques using conventional and high voltage electron microscopy. Despite gross morphological differences in endplate structure visualized at relatively low magnifications in thin sections, rat extensor digitorum longus (EDL) (fast twitch) and soleus (slow twitch) fibers cannot be distinguished on the basis of size, number, or distribution of molecular specializations of the pre-and postsynaptic junctional membranes exposed by freeze fracturing. Specializations in the cortex of the juxtaneuronal portions of the junctional folds are revealed by high voltage electron stereomicroscopy as a branching, ladder-like filamentous network associated with the putative acetylcholine receptor complexes. These filaments are considered to be involved in restricting the mobility of receptor proteins to the perineuronal aspects of the postsynaptic membrane. Although the junctional membranes of both EDL and soleus appear similar, a differential specialization of the secondary synaptic cleft was noted. The extracellular matrix in the bottom of soleus clefts was observed as an ordered system of filamentous "combs." These filamentous arrays have not been detected in EDL junctions. Examination of the extrajunctional sarcolemmas of EDL and soleus reveal additional differences which may be correlated with variations in electrical and contractile properties. For example, particle aggregates termed "square arrays" previously described in the sarcolemmas of some fibers of the rat diaphragm were observed in large numbers in sarcolemmas of EDL fibers but were seldom encountered in soleus fibers. These gross compositional differences in the membranes are discussed in the light of functional differences between fiber types.Mammalian skeletal muscles are composed of ous with respect to a number of measurable numerous individual fibers which are heterogene-parameters. Fiber "types" have been classified

show abstract

“…Turning our attention to the intercellular junctions, we know that one of these, the gap junction, may be of importance for the mediation of intercellular communication ,since in other tissues such structures have been shown to allow for electrical and metabolic coupling between individual cells. Indeed gap junctions, first recognized by conventional thin section electron microscopy [60] a n d then identified unambiguously on freeze-etch replicas [16,24,37], have been shown to be the site of a low resistance pathway between cells through which ions and small molecules (mw < 500) can diffuse freely from one cell to another [21,55]. So far, islet cells have been described to make focal contacts with each other [51] (Figs.…”

Section: • 40000mentioning

confidence: 99%