From Big Medical Encyclopedia

POLAR LAW (synonym: Pflyugera law, law of polarity of irritation) — the law describing physiological changes of excitable fabric at action on it direct electric current. According to P. z. the condition of excitement of fabric arises at the time of closing of the circuit of a direct current under the cathode (a negative pole) and at disconnection of a chain under the anode (a positive pole); at the time of inclusion of a direct current excitability and conductivity under the cathode also increases and goes down under the anode. At switching off of current the return ratios are observed (see. Electrotonic phenomena ). These patterns were for the first time open in 1859 E. Pflyuger.

With the help microelectrode methods of a research (see) it is established that under the cathode during short circuit of an electric chain there is a decrease in size of membrane potential of a cell since electric current is directed from within a cell outside. In a place of application of the anode there is an increase in membrane potential that is followed by change of excitability and size of a critical level of depolarization (see. Excitability , Excitement ). The determined consistent patterns use in experimental physiology for studying of processes of membrane mechanisms of excitement, and also in neurologic and neurosurgical practice for electrodiagnosis of diseases of the motive device of the person or changes of a functional condition of structures of a nervous system.

Bibliography: Hodorov B. I. General physiology of excitable membranes, M., 1975; P f 1 ii g e r E. Untersuchungen iiber die Physiologie des Electrotonus, B., 1859.

Yu. A. Fadeyev.