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  • Fluorescence microscopy  (2)
  • Liver  (1)
  • Rat (Wistar-Kyoto)  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 144 (1995), S. 249-255 
    ISSN: 1432-1424
    Keywords: Whole cell ; Single channel ; Cesium ; Liver ; Resting potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The single channel and whole-cell properties of an inward, rectifying potassium current in cultured embryonic chick hepatocytes were studied at 20°C. In cell-attached patches, channels open upon membrane hyperpolarization and are present in about 90% of cellattached patches. With 145 mm potassium in the pipette, inward current has a slope conductance of 80 pS. The conductance is not a linear function of the external potassium concentration. Current saturates at high external potassium and has a Michaelis-Menten affinity constant of 275 mm potassium. Substitution of gluconate for chloride in the external solution has no significant effect on conductance, and the reversal potential shifts approximately 18 mV with a change in external potassium from 72.5 to 145 mm indicating potassium selectivity. Channel openings are characterized by multiple brief closures during a burst. The channel is inhibited by external cesium in a concentration-dependent manner. Block is characterized by an increased frequency of transient closures. Whole-cell dialysis with 145 mm CsCl of cells bathed in 145 mm KCl reveals time-independent inward currents that reverse at 0 mV in response to 200 msecvoltage steps. Although voltage ramps evoke currents that are 75% potassium dependent and cesium sensitive, the mean chord conductance (425 pS) indicates that less than five channels are open at any instant. We suggest that the inwardly rectifying potassium channel is partially inactivated in the dialysed hepatocyte.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 160 (1975), S. 371-387 
    ISSN: 1432-0878
    Keywords: Frog ; Chromaffin ; Classification ; Nerve endings ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The distribution and morphology of chromaffin cells in the para-aortic region and in the ganglia of the paravertebral sympathetic chain was studied with fluorescence histochemistry and electron microscopy. 2. Four types of chromaffin cell were distinguished largely on the basis of their vesicular content: Type I cells contain large, electron-dense vesicles (600–7000 Å) and are comparable to noradrenaline-containing cells in the adrenal gland, Type II cells contain large, vesicles (600–7000 Å) that are filled with a less electron-dense material than that in Type I cells and are comparable to adrenaline-containing cells in the adrenal gland, Type III cells contain smaller vesicles (1000–3000 Å) that are incompletely filled with an electron-dense material and may represent cells that have been depleted of their catecholamines by stimulation, Type IV cells are clearly different from the other three cell types with respect to the size and appearance of the vesicles (1000–1500 Å), nuclei and rough endoplasmic reticulum and may represent immature sympathetic neurons. 3. Nerve profiles, identified as cholinergic, were found in close apposition with all four cell types. No examples of a close association between processes of chromaffin cells and sympathetic neurons were found.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 161 (1975), S. 103-117 
    ISSN: 1432-0878
    Keywords: Tissue culture ; Chromaffin cells ; Frog ; Classification ; Phase contrast microscopy ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Extra-adrenal chromaffin cells from adult frogs were grown in tissue culture and their morphology and behaviour observed with both light and electron microscopy. 2. Two types of chromaffin cells were distinguished: Type A cells contain large, electron dense vesicles (2000–6000 Å) and are equated to Type I chromaffin cells seen in vivo, i.e. they contain noradrenaline; Type B cells contain smaller vesicles (700–2000 Å) which are incompletely filled with an electron dense material and are equated to Type III chromaffin cells seen in vivo, i.e. cells depleted of their catecholamines by stimulation. No cells comparable to Types II and IV cells in vivo were seen. 3. Close associations between the cultured chromaffin cells and sympathetic neurons were observed with the light microscope, but no examples of synaptic structures were seen in the material examined with electron microscopy in this study.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0878
    Keywords: Key words Neurotransmitter receptor ; Antibody ; Sympathetic nervous system ; Alpha-adrenergic receptor ; Iris ; Reverse transcription/polymerase chain reaction ; Rat (Wistar-Kyoto)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Expression of the α1B-adrenergic receptor was investigated immunohistochemically in the rat iris, cornea and superior cervical ganglion by using antibodies raised in chickens immunised with a peptide corresponding to a portion of the 3rd intracellular loop common to the human, hamster and rat α1B-adrenergic receptor. Antibodies stained COS and HEK cell membranes of cells transfected with DNA encoding and expressing the hamster α1B-adrenergic receptor but not membranes from cells transfected with DNA encoding and expressing the rat α1A-adrenergic receptor or the rat α1D-adrenergic receptor. Staining was abolished by preincubation of the antibodies with the peptide used for immunisation. The distribution of α1B-adrenergic receptor was examined immunohistochemically with this antibody (1BI3) and a previously characterised antibody (Ab506) raised in rabbits against the carboxyl-terminal decapeptide of the receptor. In the iris, α1B-adrenergic receptor was detected in the dilator muscle, ciliary processes and posterior epithelium but no staining was observed in the superior cervical ganglion with either antibody. By contrast, differences in tissue staining between 1BI3 and Ab506 were observed for the sphincter muscle of the iris and for the cornea. 1BI3 stained both tissues intensely, whereas Ab506 only stained the cornea weakly and the sphincter not at all. Reverse transcription/polymerase chain reaction and nucleotide sequencing confirmed the presence of mRNA encoding the epitopes recognised by 1BI3 and Ab506 in cornea and other tissues. We conclude that (1) there is a good correlation between α1B-adrenergic receptor mRNA and protein expression in the iris, (2) mRNA, but not protein, is detected in the superior cervical ganglion and (3) additional processes may regulate receptor expression in the cornea.
    Type of Medium: Electronic Resource
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