Summary
Extracellular recording of 320 neurones in the dorsal horn (L 7) were performed in cats by means of multibarrelled electrodes. Changes of cutaneous receptive field size and responsiveness to tactile stimulation induced by microelectrophoretic application of exciting (glutamic acid — GLA; homocysteic acid — HCA) and depressing (glycine — GY; and gamma-amino-butyric acid — GABA) amino acids were studied on cells giving origin to the spino-cervical tract (SCT) as well as on other unidentified dorsal horn cells (NON-SCT-neurones). Two types of SCT-neurones were distinguished.
An unexpected finding was that in most type I SCT-neurones low doses of GLA induced increased excitability but higher doses of GLA could not induce a depolarization block and very often led to a decrease in cell excitability. Recordings obtained with double-multibarrelled electrodes are very suggestive that this biphasic effect of GLA is mediated via inhibitory interneurones induced by the spreading of GLA.
In almost all type II SCT-neurones and NON-SCT-neurones GLA induced increase of excitability leading to a depolarization block at high doses. Such changes were accompanied by a considerable increase of receptive field size and responsiveness to mechanical stimulation. In all types of cells GY induced a shrinkage of the receptive field and also reduced sensitivity. In most dorsal horn cells encountered in this study cooling at thoracic level produced an increase in field size and sensitivity. GLA could induce a further increase when applied at the same time, however.
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References
Brown, A.G., Franz, D.N.: Response of spinocervical tract neurones to natural stimulation of identified cutaneous receptors. Exp. Brain Res. 7, 231–249 (1969).
Curtis, D.R., Phillis, J.W., Watkins, J.C.: The chemical excitation of spinal neurones by certain acidic amino acids. J. Physiol. (Lond.) 150, 656–682 (1960).
—, Ryall, R.W.: Pharmacological studies upon spinal presynaptic fibers. Exp. Brain Res. 1, 195–204 (1966).
—: Structure and function of inhibitory neuronal mechanisms. In: Pharmacology and Neurochemistry of mammalian central inhibitory processes. Ed. by von Euler C., S. Sköglund and U. Söderberg. New York: Pergamon Press 1968.
—: The pharmacology of spinal postsynaptic inhibition. Progr. Brain Res. Vol. 31, 171–189 (1969).
Eccles, J.C., Eccles, R.M., Lundberg, A.: Types of neurones in and around the intermediate nucleus of the lumbo-sacral cord. J. Physiol. (Lond.) 154, 89–114 (1960).
Engberg, I., Ryall, R.W.: The inhibitory action of noradrenaline and other monoamines on spinal neurones. J. Physiol. (Lond.) 185, 298–322 (1966).
—, Lundberg, A., Ryall, A.W.: Reticulospinal inhibition of interneurones. J. Physiol. (Lond.) 194, 225–236 (1968).
Fetz, E.E.: Pyramidal tract effects on spinal cord interneurones in the cat lumbar dorsal horn. J. Neurophysiol. 31, 69–80 (1968).
Gordon, G., Jukes, C.H.: Dual organization of the exteroceptive components of the cat's gracile nucleus. J. Physiol. (Lond.) 173, 263–290 (1964).
Heimer, L., Wall, P.D.: The dorsal root distribution to the substantia gelatinosa of the rat. Exp. Brain Res. 6, 89–99 (1968).
Herz, A., Zieglgänsberger, W.: The influence of microelectrophoretically applied biogenic amines, cholinomimetics and procaine on synaptic excitation in the corpus striatum. Int. J. Neuropharmacol. 7, 221–230 (1968).
—, Färber, G.: Microelectrophoretic studies concerning the spread of glutamic acid and GABA in brain tissue. Exp. Brain Res. 9, 221–235 (1969).
Hillman, P., Wall, P.D.: Inhibitory and excitatory factors influencing the receptive fields of lamina 5 spinal cord cells. Exp. Brain Res. 9, 284–306 (1969).
Hongo, T., Jankowska, E., Lundberg, A.: Postsynaptic excitation and inhibition from primary afferents in neurones of the spino-cervical-tract. J. Physiol. (Lond.) 199, 569–592 (1968).
Jänig, W., Schmidt, R.F., Zimmermann, M.: Two specific feedback pathways to the central afferent terminals of phasic and tonic mechanoreceptors. Exp. Brain Res. 6, 116–129 (1968).
Krnjević, K., Phillis, J.W.: Iontophoretic studies of neurones in the mammalian cerebral cortex. J. Physiol. (Lond.) 165, 274–304 (1963).
Lundberg, A., Oscarsson, O.: Three ascending pathways in the dorsal part of the lateral funiculus. Acta physiol. scand. 51, 1–16 (1961).
—: Integration in the reflex pathway. In: Muscular afferents and motor control (First Nobel Symp.). Ed. by R. Granit. Stockholm: Almquist & Wiksell, New York: Willy & Sons 1966.
—: The Interneurone. In: Convergence of excitatory and inhibitory action on interneurones in the spinal cord. Ed. by M.A.B. Brazier. Berkeley and Los Angeles: University of California Press 1969.
McLennan, H., Huffman, R.D., Marshall, K.C.: Patterns of excitation of thalamic neurones by amino acids and by acetylcholine. Nature (Lond.) 219, 387–388 (1968).
—: Inhibition of long duration in the cerebral cortex. A quantitative difference between excitatory amino acids. Exp. Brain Res. 10, 417–426 (1970).
Melzack, R., Wall, P.D.: Pain mechanism: a new theory. Science 150, 971–979 (1965).
Mendell, L.M.: Physiological properties of unmelinated fiber projection to the spinal cord. Exp. Neurol. 16, 316–332 (1966).
Phillis, J.W.: The pharmacology of synapses. G.A. Kerkut (Ed.). Pergamon Press 43, (1970).
Rexed, B.: The cytoarchetectonic organization of the spinal cord in the cat. J. cell. comp. Neurol. 96, 415–495 (1952).
Scheibel, M.E., Scheibel, A.B.: Terminal axonal patterns in the cat spinal cord. I. The lateral corticospinal tract. Brain Res. 2, 333–350 (1966).
Sherrington, C.S., Sowton, S.C.M.: Observations on reflex responses to single break shocks. J. Physiol. (Lond.) 49, 331–343 (1915).
Spehlman, R., Kapp, H.: Direct extracellular polarization of cortical neurones with multibar-relled microelectrodes. Arch. ital. Biol. 102, 74–94 (1964).
Szentágothai, J.: Neuronal and synaptic arrangement in the substantia gelatinosa Rolandi. J. comp. Neurol. 122, 219–232 (1964).
Taub, A.: Local, segmental and supraspinal interaction with a dorsolateral spinal cutaneous afferent system. Exp. Neurol. 10, 357–374 (1964).
Wall, P.D.: Cord cells responding to touch damage and temperature of skin. J. Neurophysiol. 23, 197–210 (1960).
—: The laminar organization of dorsal horn and effects of descending impulses. J. Physiol. (Lond.) 188, 403–423 (1967).
Werman, R., Davidoff, R.A., Aprison, M.H.: Inhibitory action of glycine on spinal neurones in the cat. J. Neurophysiol. 31, 81–95 (1968).
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Zieglgänsberger, W., Herz, A. Changes of cutaneous receptive fields of spino-cervical-tract neurones and other dorsal horn neurones by microelectrophoretically administered amino acids. Exp Brain Res 13, 111–126 (1971). https://doi.org/10.1007/BF00234080
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DOI: https://doi.org/10.1007/BF00234080