ISSN:
1432-2013
Schlagwort(e):
Key wordsβ-cells
;
Pancreas
;
Electrophysiology
;
Oscillations
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Abstract Pancreatic β-cells secrete insulin as a function of blood glucose concentration. One of the key steps in stimulus-secretion coupling is the depolarisation of the membrane and the appearance of bursts of calcium action potentials. Recently, the characteristics and glucose dependence of the oscillations in electrical activity in vivo have been described. The experiments described here were designed to determine the temporal evolution of such electrical activity when no experimental changes in the glycaemia are imposed. The absolute duration of the active and silent phases has been analysed and compared with the values obtained in vitro. We have found that in vivo, at glycaemia ranging from 6.0 to 7.5 mM, the electrical activity of the islets of Langerhans is permanently oscillatory, the mean duration of the depolarisation phase being 28 s. In general, the oscillatory pattern remains very constant for relatively long (up to 60 min) periods of time. In some experiments, slow or transitory changes in the degree of β-cell activation could be observed, as well as the existence, in a very few cases, of oscillatory non-periodic patterns.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/s004240050163
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