Summary
The spread of microelectrophoretically applied substances was investigated in the cortex and in the caudate nucleus by means of double-multi-barrelled electrodes with tip separations varying from 12–300 μ. Spike activity induced in non-spontaneously firing neurones by application of glutamate and inhibition of spontaneously firing neurones by GABA were interpreted as an effect of the substances diffusing into the immediate neighbourhood of the neurone. This interpretation seems to be acceptable, since in only a small number of tests could an indication for trans-neuronally induced firing be found.
The data obtained from dosage-response-curves, when adequately corrected, correspond to curves deduced from the diffusion equation for a diffusion coefficient of about 1.0×10−5 (cm2/sec).
The mean threshold dosage for activation of spike activity by glutamate was found to be 0.25 mM. When glutamate was applied from the remote electrode the threshold concentration was achieved with comparatively lower dosages. This discrepancy is interpreted in terms of different areas of distribution.
The mean distance between neurone and electrode was found to be about 20 μ when neurones with a satisfactory spike/noise ratio were recorded. This field was found to often be smaller than that occupied by the substances, even at low dosages.
Similar content being viewed by others
References
Amassian, V.E.: Microelectrode studies of the cerebral cortex. Int. Rev. Neurobiol. 3, 67–136 (1961).
Bebl, S., and H. Waelsch: Determination of glutamic acid, glutamine and γ-amino-butyric acid and their distribution in brain tissues. J. Neurochem. 3, 161–169 (1958).
Bourke, R.S., E.S. Greenberg and D.B. Tower: Variations of cerebral cortex fluid spaces in vivo as a function of species brain size. Amer. J. Physiol. 208, 682–692 (1965).
Bozler, E., and K. Cole: Electric impedance and phase angle of muscle in rigor. J. cell. comp. Physiol. 6, 229–241 (1935).
Carslaw, H.S., and J.C. Jaeger: Conduction of heat in solids. 2nd Ed., page 261. Oxford: University Press 1959.
Curtis, D.R.: Microelectrophoresis. In: Physical techniques in biological research, vol. V, pp. 144–190. Ed. by W.L. Nastuk. New York: Academy Press 1964.
—: Pharmacology and Neurochemistry of mammalian central inhibitory processes. In: Structure and function of inhibitory neuronal mechanisms, pp. 429–456. Ed. by U.S. von vEuler, S. Skoglund and U. Söderberg. Oxford: Pergamon Press 1968.
—, D.D. Perrin and J.C. Watkins: The excitation of spinal neurones by the ionophoretic application of agents which chelate calcium. J. Neurochem. 6, 1–20 (1960).
Davson, H., and M. Bradbury: The extracellular space of the brain. In: Biology of neuroglia. Progress in Brain Res. 15, 124–133 (1965).
De vRobertis, E.: Some new electronmicroscopical contributions to the biology of neuroglia. In: Biology of neuroglia. Progress in Brain Res. 15, 1–11 (1965).
Elul, R.: Dipoles of spontaneous activity in the cerebral cortex. Exp. Neurol. 6, 285–299 (1962).
Globus, A., and A.B. Scheibel: Pattern and field in the cortical structure. J. comp. Neurol. 131, 155–172 (1967).
Herz, A., M. Wickelmaier u. A.C. Nacimiento: Über die Herstellung von Mehrfachelektroden für die Mikroelektrophorese. Pflügers Arch. ges. Physiol. 284, 95–98 (1965).
—, u. A.C. Nacimiento: Über die Wirkung von Pharmaka auf Neurone des Hippocampus nach mikroelektrophoretischer Verabfolgung. Naunyn-Schmiedebergs Arch. exp. Path. Pharmak. 251, 295–314 (1965).
—, u. Hj. von vFreytag-Loringhoven: Über die synaptische Erregung im Corpus striatum und deren antagonistische Beeinflussung durch mikroelektrophoretisch verabfolgte Glutaminsäure und Gamma-Aminobuttersäure. Pflügers Arch. ges. Physiol. 299, 167–184 (1968).
-, W. Zieglgänsberger and Hj. von Freytag-Loringhoven: Fields of focus potentials in the caudate nucleus and their development following microelectrophoretically applied substances. Electroenceph. clin. Neurophysiol. (in press) (1969).
Johnestone, R.M., and P.G. Scholefield: Transport phenomena in brain. J. Neurochemistry, 2nd Ed. by K. Elliott, J. Page and J. Quastel Eds. Springfield/Ill.: Charles C. Thomas Publ. 1962.
Katz, B.: The electrical properties of the muscle fibre membrane. Proc. roy. Soc. B 135, 506–534 (1948).
Krnjević, K.: Microiontophoretic studies on cortical neurones. Int. Rev. Neurobiol. 7, 41–97 (1964).
—, and J.F. Mitchell: Diffusion of acetylcholine in agar gels and in the isolated rat diaphragm. J. Physiol. (Lond.) 153, 562–572 (1960).
—, and J.W. Phillis: Iontophoretic studies of neurones in the mammalian cerebral cortex. J. Physiol. (Lond.) 165, 274–304 (1963).
Kuffler, S.W., and J.G. Nicholls: The physiology of neuroglia cells. Ergebn. Physiol. 57, 1–90 (1966).
Longsworth, L.G.: Diffusion measurements, at 25° of aquous solutions of amino acids, peptides and sugars. J. Amer. ehem. Soc. 75, 5705–5709 (1953).
Mountcastle, V.B., P.H. Davis and A.L. Berman: Response properties of neurones of cat's somatic sensory cortex to peripheral stimuli. J. Physiol. (Lond.) V 20 (1967).
Nicholls, J.G., and S.W. Kuffler: Extracellular space as a pathway for exchange between blood and neurones in the central nervous system of leach: Ionic composition of glia cells and neurones. J. Neurophysiol. 27, 645–673 (1964).
Pappenheimer, J.R.: Passage of molecules through capillary walls. Physiol. Rev. 33, 387–423 (1953).
Rosenthal, P., W. Woodbury and H.D. Patton: Dipole characteristics of pyramidal cell activity in cat postcruciate cortex. J. Neurophysiol. 29, 612–625 (1966).
Salmoiraghi, G.G.: Electrophoretic administration of drugs to individual nerve cells. In: Neuro-psychopharmacology, Vol. 3, 219–231 (1964).
Szentágothai, J.: The anatomy of complex integrative units in the nervous system. In: Recent Development of Neurobiology in Hungary, Vol. I. Ed. by K. Lissak. Budapest (1967).
Van vHarreveld, A., and S.K. Malhotra: Extracellular space in the cerebral cortex of the mouse. J. Anat. (Lond.) 101, 197–207 (1967).
Verzeano, M., and K. Negishi: Neuronal activity in wakefullness and in sleep. In: Nature of Sleep. CIBA-Symposium. Ed. by C. Wolstenholme and M. O'Connor. London: Churchill 1961.
Zieglgänsberger, W., A. Herz and Hj. vTeschemacher: Electrophoretic release of tritiumlabelled glutamic acid from micropipettes in vitro. Brain Res. 15, 298–300 (1969).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Herz, A., Zieglgänsberger, W. & Färber, G. Microelectrophoretic studies concerning the spread of glutamic acid and GABA in brain tissue. Exp Brain Res 9, 221–235 (1969). https://doi.org/10.1007/BF00234456
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00234456