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  • 1970-1974  (4)
  • Glandula submaxillaris  (2)
  • Acetazolamid  (1)
  • Cell & Developmental Biology  (1)
  • 1
    Electronic Resource
    Electronic Resource
    A microperfusion investigation of bicarbonate secretion by the rat submaxillary gland (1970)
    Springer
    Pflügers Archiv 319 (1970), S. 185-199 
    Details
    ISSN: 1432-2013
    Keywords: Submaxillary Gland ; Bicarbonate Secretion ; Microperfusion ; Acetazolamide ; Carbachol ; Submaxillardrüse ; Bicarbonatsekretion ; Mikroperfusion ; Acetazolamid ; Carbachol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bicarbonate transport in the rat submaxillary main duct has been studied by microperfusion. Bicarbonate was concentrated in the duct lumen against an electrochemical gradient and the equilibrium concentration was estimated to be 56.5 mEq/l±3.1 (S.E.M.,n=11). The secretory mechanism could not be inhibited by 6 mMolar cyanide although such concentrations caused marked inhibition of both net sodium efflux and net potassium influx. Bicarbonate secretion in the main duct was not inhibited by acetazolamide whether applied from the duct lumen or given intravenously. Similarly, the drug was without effect on bicarbonate excretion by the intact gland even when maximum excretory rates had been induced with carbachol. It was concluded that catalytic hydration of carbon dioxide to carbonic acid was not a rate-limiting step in the bicarbonate secretory process. The data did not permit a distinction to be made between a bicarbonate secretory processper se and a process of either H+ reabsorption or OH− secretion. The parasympathomimetic agent, carbachol, when given parenterally was found to increase sharply the net influx of bicarbonate into the microperfused main duct as well as to reduce net sodium efflux and net potassium influx. Previously it had been postulated that final saliva was formed in two stages. First a plasma-like primary secretion was formed at a rate depending on the degree of stimulation, and second, the primary secretion was modified in the gland duct system by reabsorptive and secretory processes whose transport rates were presumed to be independent of the degree of stimulus. It now becomes necessary to postulate that stimulation can act on electrolyte transport at both primary and secondary levels; at present, however, no data are available to show whether appreciable net water influx can ever occur at the secondary level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586449
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of a sympatho- and a parasympathomimetic drug on the electrolyte concentrations of primary and final saliva of the rat submaxillary gland (1971)
    Springer
    Pflügers Archiv 327 (1971), S. 285-302 
    Details
    ISSN: 1432-2013
    Keywords: Parasympathicomimetic ; Sympathicomimetics ; Submaxillary Gland ; Potassium Secretion ; Bicarbonate Secretion ; Isoproterenol ; Carbachol ; Parasympathomimetica ; Sympathomimetica ; Glandula submaxillaris ; Kalium-Sekretion ; bicarbonat-Sekretion ; Isoproterenol ; Carbachol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Salivary glands are generally supposed to produce their secretions in 2 stages: 1. A plasma-like secretion is formed in the acinar-intercalated duct region of the gland, the rate of production but not the electrolyte composition of this fluid being increased by gland stimulation. 2. This primary saliva is then modified during its passage along the gland duct system by processes of Na reabsorption and K and HCO3 secretion. In general terms this hypothesis accounts for the behaviour of salivary glands undergoing parasympathetic or parasympathomimetic stimulation. However, when sympathetic or sympathomimetic stimulation occurs the electrolyte excretory patterns are anomalous and the 2-stage hypothesis cannot easily account for them. Thus, after sympathomimetic stimulation the rat submaxillary saliva was found to be nearly isotonic with [K]=150 mEq/l and [HCO3]=135 mEq/l, the concentrations being independent of flow rate. To elucidate this problem the Na, K and HCO3 excretory curves in rat submaxillary saliva have been studied in animals undergoing parasympathomimetic, sympathomimetic and combined sympatho- and parasympathomimetic stimulation and these have been compared with the electrolyte concentrations of primary saliva obtained at rest and after stimulation. The results suggest: 1. That both types of drug stimulate formation of an approximately plasma-like primary secretion whose composition changes only slightly with stimulation. Parasympathomimetics, however, cause production of 6–8 times more primary fluid per unit time than sympathomimetics. 2. That contrary to all previous opinion, the drugs have a direct action at the ductal level where they stimulate secretion of K and HCO3. At this site the effects of the two types of drug are approximately equal which explains why sympathetic saliva is so rich in K and HCO3. The ductal action of parasympathomimetics may also explain why ductal secretion of both K and HCO3 do not undergo saturation as gland stimulation is progressively increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00588449
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Amicroperfusion investigation of the effects of a sympathomimetic and a parasympathomimetic drug on water and electrolyte fluxes in the main duct of the rat submaxillary gland (1971)
    Springer
    Pflügers Archiv 327 (1971), S. 303-323 
    Details
    ISSN: 1432-2013
    Keywords: Parasympathomimetics ; Sympathomimetics ; Electrolyte Transport ; Submaxillary Gland ; Microperfusion ; Parasympathicomimetica ; Sympathicomimetica ; Elektrolyttransport ; Glandula submaxillaris ; Mikroperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous studies on the intact rat submaxillary gland led to the hypothesis that sympathomimetic and parasympathomimetic drugs, in addition to stimulating glandular production of primary saliva, also stimulated secondary secretion of K and HCO3 by the striated and excretory ducts. It was postulated that parasympathomimetics were more effective stimulants than sympathomimetics atthe primary level but atthe secondary level the two types of drug had actions that were of approximately the same magnitude and that, when administered together, the effects of the drugs were additive. To test this hypothesis the effects of a parasympathomimetic drug (carbachol) and a sympathomimetic drug (isoproterenol) on nett electrolyte transport and transepithelial electrical potential differences were studied in the perfused main duct of the rat submaxillary gland. It was found: 1. That both carbachol and isoproterenol stimulated ductal secretion of bicarbonate irrespective of the electrolyte composition of the perfusion fluid. 2. Both drugs stimulated a parallel nett secretion of potassium when the perfusion fluid contained a low concentration of NaCl. 3. When the lumen contained a high concentration of NaCl, ductal Na reabsorption and K secretion were reduced and HCO3 secretion was accomplished partly in exchange for chloride and partly in parallel with K secretion. 4. In supra-maximal doses the effects of both drugs were of the same order of magnitude and when administered together the effect was always greater than that which could be produced by the same doses of either drug alone. It is concluded that, during pharmacological stimulation of the submaxillary gland, stimulation of ductal secretion of K and HCO3 did indeed occur and that such an occurrence could account for anomalies previously observed in the electrolyte excretory patterns of the intact gland undergoing parasympathomimetic and sympathomimetic stimulation. Since the electrolyte excretory patterns found in saliva collected after nerve and pharmacological stimulation are quite similar it was felt that stimulation of ductal K and HCO3 secretion probably also occurred in this and other salivary glands during nerve stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00588450
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  • 4
    Electronic Resource
    Electronic Resource
    Embryonic vertebrate central nervous system: Revised terminology (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 166 (1970), S. 257-261 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The layers and cells of the early developing central nervous system lack direct counterparts in the adult and must be designated by a special terminology. The inconsistent and inaccurate language now in use leads to misunderstanding and a revision is proposed in which the four fundamental zones are termed the ventricular, subventricular, intermediate, and marginal zones. Each is defined according to the form, behavior, and fate of its constituent cells. All neurons and macroglia of the central nervous system can be derived from these developmental zones.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091660214
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    Paper (German National Licenses)
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