Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (1)
  • 1985-1989  (1)
  • 1930-1934
  • AbbreviationsBIC bicuculline methiodide  (1)
  • Beta (storage root)  (1)
Material
Years
  • 1995-1999  (1)
  • 1985-1989  (1)
  • 1930-1934
Year
  • 1
    ISSN: 1432-2048
    Keywords: Beta (storage root) ; Osmotic pressure ; Salt uptake ; Sucrose mobilisation ; Turgor pressure ; Vacuole (solute content)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The changes in turgor pressure that accompany the mobilisation of sucrose and accumulation of salts by excised disks of storage-root tissue of red beet (Beta vulgaris L.) have been investigated. Disks were washed in solutions containing mannitol until all of their sucrose had disappeared and then were transferred to solutions containing 5 mol·m-3 KCl+5 mol·m-3 NaCl in addition to the mannitol. Changes in solute contents, osmotic pressure and turgor pressure (measured with a pressure probe) were followed. As sucrose disappeared from the tissue, reducing sugars were accumulated. For disks in 200 mol·m-3 mannitol, the final reducing-sugar concentration equalled the initial sucrose concentration so there was no change in osmotic pressure or turgor pressure. At lower mannitol concentrations, there was a decrease in tissue osmotic pressure which was caused by a turgor-driven leakage of solutes. At concentrations of mannitol greater than 200 mol·m-3, osmotic pressure and turgor pressure increased because reducing-sugar accumulation exceeded the initial sucrose concentration. When salts were provided they were absorbed by the tissue and reducing-sugar concentrations fell. This indicated that salts were replacing sugars in the vacuole and releasing them for metabolism. The changes in salf and sugar concentrations were not equal because there was an increase in osmotic pressure and turgor pressure. The amount of salt absorbed was not affected by the external mannitol concentration, indicating that turgor pressure did not affect this process. The implications of the results for the control of turgor pressure during the mobilisation of vacuolar sucrose are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 185 (1999), S. 479-491 
    ISSN: 1432-1351
    Keywords: Key words Iontophoresis ; Inferior colliculus ; Amphibian ; Rana pipiens ; Bicuculline ; GABA ; AbbreviationsBIC bicuculline methiodide ; CF characteristic frequency ; DNLL dorsal nucleus of the lateral lemniscus ; eFTC excitatory frequency tuning curve ; GABAγ-amino butyric acid ; IC inferior colliculus ; iFTC inhibitory frequency tuning curve ; PB phasic burst ; PL-1 primary-like 1 ; PL-2 primary-like 2 ; PL-3 primary-like 3 ; PSTH post-stimulus time histogram ; SPL sound pressure level ; SRN superficial reticular nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The functional role of GABAergic inhibition in shaping the frequency tuning of 96 neurons in the torus semicircularis of the leopard frog, Rana pipiens, was studied using microiontophoresis of the GABAA receptor antagonist, bicuculline methiodide. Bicuculline application abolished, or reduced in size, the inhibitory tuning curves of 72 neurons. In each case, there was a concommitant broadening of the excitatory tuning curve such that frequency-intensity combinations that were inhibitory under control conditions, became excitatory during disinhibition with bicuculline methiodide. These effects were observed irrespective of the excitatory tuning curve configuration prior to bicuculline methiodide application. Results indicate an important role for GABA-mediated inhibition in shaping the frequency selectivity of neurons in the torus semicircularis of the leopard frog. Bicuculline application also affected several other response properties of neurons in the leopard frog torus. Disinhibition with bicuculline methiodide increased both the spontaneous firing rate (18 cells) and stimulus-evoked discharge rate (81 cells) of torus neurons, decreased the minimum excitatory threshold for 18 cells, and altered the temporal discharge pattern of 47 neurons. Additional roles for GABAergic inhibition in monaural signal analysis are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...