From Big Medical Encyclopedia

MICROIONOPHORESIS (grech, mikros small + ion[s] + phoresis execution, transferring; synonym: microiontophoresis, microelectrophoresis) — a method of introduction to a cell or leading to it any substances capable to dissociate on ions. It is at the same time possible to carry out registration of bioelectric activity of this cell. The m is one of the main modern methods neyrofiziol., neyrofarmakol. and neurochemical, researches. It is widely applied to studying of processes of synoptic transfer, hemoretseptivny properties and ionic mechanisms of plasma membranes of various cellular elements, to a research of mechanisms of effect of biologically active agents at the cellular level, processes of nervous excitement, etc. M. was for the first time applied by Nastuk (W. L. Nastuk) in 1953 at pharmakol, studying of the mechanism of neuromuscular transmission it is also modified by Curtice and Ekkls (D. R. Curtis, R.М. Eccles) for a research of the central neurons.

Ability is the cornerstone of a method ions (see) and other charged particles to the directed movement under the influence of direct electric current. In need of studying of several parameters in the studied object it is possible to apply multichannel glass electrodes of various design (see. Microelectrode method of a research ). At the same time a part of canals of microelectrodes fill with solutions of the studied substances. One channel, with the help to-rogo register bioelectric potential (see), fill with electrolyte (usually 2 — 3 M NaCl or KCl solution). Positively charged ions and particles of substances are entered by currents of the positive direction, and negatively charged — negative currents (these currents are called foretichesky currents). For the purpose of the prevention of spontaneous release of substances from channels of microelectrodes through them it is constant, excluding only time of an injection, the currents opposite on a sign foretichesky — «holding», or «locking», currents are passed. For elimination of possible harmful effects of electric current on the studied cells use the «compensating» current equal to the algebraic sum of the foretichesky and holding currents therefore the balance of the general potential on a tip of a multichannel microelectrode is reached.

The m gained distribution in neyrofiziol. and pharmakol, practice. However M. has the shortcomings consisting in impossibility of implementation of a mikroionoforetichesky injection of a number of slabodissotsiiruyushchy and high-molecular substances and definitions of exact concentration of active ingredient at application.

Bibliography: Rajevski V. V. and Sherstnev V. V. Apparat for mikroionoforetichesky administration of biologically active agents, Zhurn. vyssh. nervn. deya-teln., t. 27, century 1, page 211, 1977; Curtis D. R. Microelectrophoresis, in book: Phys. techn. biol, res., ed. by W. L. Nastuk, v. 5, p. 144, N. Y. — L., 1964, bibliogr.; Salmoiraghi G. C. a. Stefa-n i s C. N. A critique of iontophoretic studies of central nervous system neurons, Int. Rev. Neurobiol., v. 10, p. 1, 1967, bibliogr.

V. V. Sherstnev.