Theoretical treatment of ohmic and rectifying properties of electrolyte filled micropipettes.

نویسنده

  • C C Krischer
چکیده

Für Mikropipetten, wie sie in elektrophysiologischen Impedanzmessungen, Stimulation und Ioneninjektion verwendet werden, wird ein Modell angenommen, das aus einem isolierenden Kegel­ stumpfmantel besteht, dessen Oberfläche eine negative Ladung trägt, die durch eine leitende Kationenschicht neutralisiert wird. Unter den einfachsten Bedingungen sei die Elektrode mit einem gewöhnlichen Elektrolyten wie KCl gefüllt und umgeben. Mit Hilfe einer Konstanten b [cm], die das Verhältnis von Volumenzu Oberflächenleitfähigkeit darstellt, wird entlang der Kegelachse das Verhältnis von Ionen in der Doppelschicht zu Ionen im Volumenelektrolyten berechnet. Für den Fall, daß der Radius der Öffnung /■0[cm]^> b [cm] herrscht Volumenleitung in der Öffnung. Die elektrische Charakteristik ist ohmisch. Für r0 b ist die Öffnung durch Doppelschichtladungen ver­ stopft. Strom polarisiert diesen Stopfen derart, daß in einer Stromrichtung der Elektrolyt im stark beengten Innenraum der Elektrode angereichert (Widerstandsabnahme), in der anderen verdünnt wird (Widerstandszunahme). Die dargelegten Eigenschaften stromführender Mikropipetten werden in Hinblick auf ihre Bedeutung bei elektrophysiologischen Anwendungen diskutiert.

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عنوان ژورنال:
  • Zeitschrift fur Naturforschung. Teil B, Chemie, Biochemie, Biophysik, Biologie und verwandte Gebiete

دوره 24 2  شماره 

صفحات  -

تاریخ انتشار 1969