摘要:

AbstractThe previously described ability of reserpine and parachlorophenylalanine to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of the bat was investigated. Lipid droplet accumulation was assessed qualitatively by light microscopy and quantitatively by morphometric analysis of electron micrographs. An hypothesis that the action of the drugs was an indirect one, mediated by the cardiac adrenergic innervation, was framed and tested. Lipid droplet accumulation occurred during a time of intense sympathetic activity, that of arousal from hibernation. The ability of the two drugs to produce the effect was antagonized by prior sympathectomy with 6–dopamine. The effect was mimicked by administration of exogenous norepinephrine together with inhibitors of its catabolic enzymes, monoamine oxidase and catechol‐omethyl transferase. These observations are all consistent with the initial hypothesis and raise the possibility that endogenous norepinephrine in the cardiac sympathetic innervation might be, at least potentially, auto‐

ISSN:0003-276X    

DOI:10.1002/ar.1091810202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractBy use of lanthanum tracer and freeze‐fracture procedures it was found that granulosa‐lutein cells of the pregnant mouse and rat ovaries are connected by gap junctions and septate‐like zones of contact. Lutein cell gap junctions enlarge and become partially internalized by the end of the first week of gestation. Expansion of the gap junction domain appears to be due initially to intercalation of particles along borders of small gap junctions devoid of smaller non‐junctional particles. The number of gap junction lined processes appearing at the cell border increases concomitantly with hypertrophy of the lutein cell during the second week of pregnancy. Strands of particulate or grooved membrane emanate from the margin of larger gap junctions undergoing interiorization. Most large gap junctions are intimately associated with elements of the smooth endoplasmic reticulum. Spherical gap junctional profiles assume a deeper location in the lutein cell and may form concentric arrays by term while true surface gap junctions appear to fragment in the post‐partum corpus luteum. The modifications observed are interpreted with respect to biogenesis of the gap junction and the hormonal control of lutein cell

ISSN:0003-276X    

DOI:10.1002/ar.1091810203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractElectron microscopy of the rat cardiac ganglion shows occurence of small granule‐containing cells that form reciprocal synaptic junctions with cholinergic terminals. At the synaptic junctions which are from axon to granule‐containing cell, the intraaxonal vesicles are clustered against the junctional axolemma, but dense‐cored vesicles in the postynaptic cell do not cluster towards the membrane densities in these synapses. By contrast, the synaptic zone polarized in the opposite direction shows an absence of axonal vesicles in close proximity to the postsynaptic axolemma, but there is a marked aggregation of dense‐cored vesicles towards the presynaptic specializations of granule‐containing cells. The synaptic zones are multifocal rather than bifocal, and the minimal distance separating each synaptic zone is about 0.3 μ. These findings may indicate that cholinergic excitation of some or all granule‐containing cells causes a reciprocal inhibition of one or more cholinerg

ISSN:0003-276X    

DOI:10.1002/ar.1091810204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractThe surface patterns of the oviduct ofGallus domesticuswere examined by scanning electron microscopy (SEM) using several preparatory techniques. Ciliated epithelial cells predominate throughout the oviduct with nonciliated cells approaching an equal proportion in the magnum and isthmus. Short, randomly oriented mucosal folds which characterize the infundibulum increase in height and longitudinal orientation as they approach the magnum. Here and in the isthmus they broaden and become dimpled with glandular apertures. The folds narrow again in the uterus and vagina. Cryofracture followed by SEM demonstrate the deeper mucosal folds and submucosal tubular system.

ISSN:0003-276X    

DOI:10.1002/ar.1091810205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractThe ciliary ultrastructure is studied in the ciliated cells of the thymic cysts of the “nude” mouse. The cilium is made up of two segments: the intracellular basal body and the extracellular cilium shaft.The basal body extends in a rootlet and demonstrates three annexes: basal foot, anchoring system and tonofibrillar web. The rootlet, composed of one central and nine peripheral chambers, is closely and constantly associated with smooth endoplasmic reticulum. The classical periodicity of the basal foot can be explained by its internal structure. The anchoring system binds the upper part of the basal body to the cell membrane. The cilium shaft is divided into four segments: implantation base, proximal segment, intermediate segment and tip. The details of particular structures in the implantation base and in the proximal segment are given on transverse and longitudinal sections. In the intermediate part, a peculiar desmosome‐like structure, binds some doublets with the ciliary membrane. At the tip level, A tubules end up in an opaque plate and membranes are covered with several intricated cr

ISSN:0003-276X    

DOI:10.1002/ar.1091810206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractThe intestinal mucosa of the platypus takes the form of numerous transverse surface folds. These folds are made up of a lamina propria covered by pseudostratified epithelium which lies on a thick modified basement membrane. The cells of the intestinal epithelium consist of columnar cells which generally resemble typical intestinal epithelium and cuboidal cells, which are undifferentiated in appearance, show few organelles and possess an electron lucent cytoplasm. Numerous desmosomes are found between the adjacent cell membranes of both cell types. Villi are absent and appear to be represented by the large surface folds.Intestinal glands are composed of columnar epithelium similar to that found in the intestinal glands of other mammalian species. Groups of these glands drain into common tubular ducts which follow a tortuous course and empty into the intestinal lumen between the surface folds.The peculiar morphological features of the platypus intestinal mucosa raise questions concerning traditional concepts of intestinal gland formation as well as the origin and migration of intestinal epithelium with regard to this particular species.

ISSN:0003-276X    

DOI:10.1002/ar.1091810207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractWallerian degeneration in the severed newt's (Triturus viridescens) optic nerve is complete between the 10–14th post operative day (p.o.d.). Consequently, the newt optic nerve displays one of the most rapid degenerative responses yet reported for the central nervous system of vertebrates. In most cases it also exhibits the speed of degenerative phenomena in the vertebrate peripheral nervous system.The degeneration of unmyelinated axons is most rapid and is completed by 2–3 p.o.d., compared to myelinated axons, most of which degenerate between 2–10 p.o.d. Myelin ring formation (vesicular transformation) is the principal form of lamellar breakdown and occurs in a highly organized manner which can be clearly staged.The glial cell response to Wallerian degeneration is two‐fold: cytoplasmic hypertrophy and myelin‐lytic. Glial hypertrophy subsides by the 10–14 p.o.d. with the ingrowth of numerous regenerating nerve fibers. The myelin‐lytic response accounts for most of the myelin destruction. Leukocyte‐like and microglialike cells also participate in myelin breakdown but to

ISSN:0003-276X    

DOI:10.1002/ar.1091810208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractOvariectomized rabbits received3H‐estradiol via an ear vein and were killed one hour later. Autoradiograms were prepared and exposed up to six months. Labeled cells, as indicated by many silver grains over the nucleus of a neuron, were found in many nuclei of the brain. Thus, the bed nucleus of the stria terminalis had labeled cell bodies. The stria terminalis leads into the medial preoptic area where great numbers of cells concentrated the estrogen. Farther into the hypothalamus the labeled cells were numerous in the ventromedial and arcuate nuclei. Other locations with labeled cells were the lateral septal nucleus and nucleus accumbens septi, the periventricular preoptic nucleus, anterior hypothalamic nucleus, nucleus supraopticus diffusus, posterior hypothalamic nucleus, and premammillary nucleus. The labeled cells could be followed into the central gray surrounding the aqueduct of Sylvius. The amygdaloid nuclei, and in particular the medial amygdaloid nucleus, had labeled cells as did the most ventral posterior part of the hippocampal cortex. The results are discussed in comparison with those in the rat, and with reference to physiologic dat

ISSN:0003-276X    

DOI:10.1002/ar.1091810209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091810210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091810201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY