We report here our studies of the effects of the inhibitory transmitters glycine and GABA on monosynaptic EPSP recorded in response to microstimulation of presynaptic fibers (PF PSP) close to the bodies of motoneurons in the isolated frog spinal cord. Monosynaptic PF PSP had two components, mediated by AMPA/KA and NMDA receptors. Blockade of NMDA receptors was used to analyze the characteristics of the AMPA/KA and NMDA components of PF PSP. The amplitude of the NMDA component was 20% of PF PSP amplitude. The areas under the curves of the AMPA/KA and NMDA components were 78% and 22% respectively of the area of the PF PSP. Glycine and GABA had little effect on PF PSP, but significantly decreased the decay time constant (τdecay), by an average of 33.4 ± 4.0% (n = 18) on application of glycine and by 40.2 ± 3.6% (n = 18) on application of GABA. Blockade of NMDA receptors with DL-2-amino-5-phosophonovaleric acid (AP5) decreased the effects of glycine and GABA on the time constant. Effects were reversible and the amplitude and time characteristics of responses recovered in normal solution. Assessment of the inhibitory influences of glycine and GABA on each of the components of PF PSP showed that suppression of the NMDA component produced a greater proportionate effect than suppression of the AMPA/KA component. These results show that the inhibitory effects of glycine and GABA on the monosynaptic EPSP of motoneurons are mediated mainly by the NMDA component, with a small influence from the AMPA/KA component.
Similar content being viewed by others
References
A. A. Velumyan, “Intracellular analysis of the effects of microapplication of various amino acids on lumbar motoneurons in the frog Rana ridibunda,” Zh. Evolyuts. Biokhim. Fiziol., 13, No. 3, 407–409 (1977).
N. I. Kalinina, G. G. Kurchavyi, D. V. Amakhin, and N. P. Veselkin, “Differences in the activation of inhibitory receptors of motoneurons in the frog Rana ridibunda by glycine and their interaction,” Ros. Fiziol. Zh., 94, No. 9, 1005–1016 (2008).
N. I. Kalinina, G. G. Kurchavyi, and N. P. Veselkin, “Inhibitory regulation of the responses of glutamate receptors in frog motoneurons,” Ros. Fiziol. Zh., 98, No. 5, 575–587 (2012).
N. I. Kalinina, G. G. Kurchavyi, and B. T. Ryabov, “Equilibrium potential of monosynaptic EPSP in frog motoneurons,” Neirofizilogiya, 18, No. 4, 534–541 (1986).
G. G. Kurchavyi, N. I. Kalinina, and N. P. Veselkin, “The different sensitivities of the synaptic inputs of frog motoneurons to excitatory amino acid antagonists,” Zh. Evolyuts. Biokhim. Fiziol., 39, 144–153 (2003).
G. G. Kurchavyi, N. I. Kalinina, and N. P. Veselkin, “Effects of GABA and glycine on postsynaptic potentials in frog motoneurons,” Zh. Evolyuts. Biokhim. Fiziol., 41, No. 6, 522–531 (2005).
G. G. Kurchavyi, N. I. Kalinina, and N. P. Veselkin, “The contributions of glycine and GABAA receptors to the generation of inhibitory postsynaptic potentials in frog spinal cord motoneurons,” Ros. Fiziol. Zh., 96, No. 6, 553–565 (2010).
G. G. Kurchavyi, N. I. Kalinina, Z. E. Mel’yan, and N. P. Veselkin, “Potentiation of postsynaptic potentials in response to glutamate and agonists in motoneurons in the frog Rana ridibunda,” Zh. Evolyuts. Biokhim. Fiziol., 31, No. 4, 430–443 (1995).
Z. A. Tamarova, “Excitatory postsynaptic potentials in frog lumbar motoneurons evoked by stimulation of muscle and cutaneous nerves,” Fiziol. Zh. SSSR, 63, No. 6, 806–813 (1977).
J. Eccles, The Physiology of Synapses [Russian translation], Mir, Moscow (1964).
P. R. Adams and D. B. Pixner, “Excitation of frog spinal motoneurones by glycine,” J. Physiol., 240, 67P–58P (1975).
A. L. Babalian and A. I. Shapovalov, “Synaptic actions produced by individual ventrolateral tract fi bres in frog lumbar motoneurones,” Exp. Brain Res., 54, 551–563 (1984).
E. Ben-Ari, J.-L. Gaiarsa, R. Tyzio, and R. Khazipov, “GABA: A pioneer transmitter that excites immature neurons and generates primitive oscillations,” Physiol. Rev., 87, 1215–1284 (2007).
A. Cupello, “Neuronal transmembrane chloride electrochemical gradient: a key player in GABA A receptor activation physiological effect,” Amino Acids, 24, No. 4, 335–346 (2003).
J. Davies, E. H. Evans, A. W. Jones, et al., “Differential activation and blockade of excitatory amino acid receptors in the mammalian and amphibian central nervous systems,” Comp. Biochem. Physiol., 72C, 211–224 (1982).
M. Farrant and K. Kaila, “The cellular, molecular and ionic basis of GABA(A) receptor signalling,” Prog. Brain Res., 160, 59–87 (2007).
L.-Y. Fu and A. N. van den Pol, “GABA excitation in mouse hilar neuropeptide Y neurons,” J. Physiol., 579, No. 2, 445–464 (2007).
A. S. Hyngstrom, M. D. Jonson, and C. J. Heckman, “Summation of excitatory and inhibitory synaptic inputs by motoneurons with highly active dendrites,” J. Neurophysiol., 99, 1643–1652 (2008).
Ye. Jiang-Hong, “Regulation of excitation by glycine receptors,” in: Inhibitory Regulation of Excitatory Neurotransmission, M. G. Darlison (ed.), Springer (2008).
W. Kilb, I. L. Hanganu, A. Okabe, et al., “Glycine receptors mediate excitation of subplate neurons in neonatal rat cerebral cortex,” J. Neurophysiol., 100, 698–707 (2008).
E.-A. Lee, J.-H. Choi, M. Nakamura, et al., “Presynaptic glycine receptors facilitate spontaneous glutamate release onto hilar neurons in the rat hippocampus,” J. Neurochem., 109, 275–286 (2009).
P. Legendre, “The glycinergic inhibitory synapse,” Cell. Mol. Life Sci., 58, 760–793 (2001).
N. J. Leidenheimer, “Regulation of excitation by GABAA receptor internalization,” in: Inhibitory Regulation of Excitatory Neurotra nsmission, M. G. Darlison (ed.), Springer (2008).
S. Minota, T. Miyazaki, M. Y. Wang, et al., “Glycine potentiates NMDA responses in rat hippocampal CA1 neurons,” Neurosci. Lett., 100, 237–242 (1989).
S. V. Ovsepian and N. P. Vesselkin, “Dual effect of GABA on descending monosynaptic excitatory postsynaptic potential in frog lumbar motoneurons,” J. Neurosci., 129, 639–646 (2004).
J. C. Rekling, G. D. Funk, D. A. Bayliss, et al., “Synaptic control of motoneuronal excitability,” Physiol. Rev., 80, No. 2, 767–852 (2000).
V. Stein and R. A. Nicoll, “GABA generates excitement,” Neuron, 37, No. 3, 375–378 (2003).
R. Turecek and L. O. Trussell, “Presynaptic glycine receptors enhance transmitter release at mammalian central synapse,” Nature, 411, No. 6837, 587–590 (2001).
M. C. Walker and A. Semyanov, “Regulation of excitability by extrasynaptic GABAA receptors,” in: Inhibitory Regulation of Excitatory Neurotransmission, M. G. Darlison (ed.), Springer (2008).
K. Zito and C. Scheuss, “NMDA-receptor function and physiological modulation,” in: Encyclopedia of Neuroscience, L. R. Squire (ed.) (2009), Vol. 6, pp. 1157–1164.
Author information
Authors and Affiliations
Corresponding author
Additional information
Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 101, No. 8, pp. 885–897, August, 2015.
Rights and permissions
About this article
Cite this article
Kalinina, N.I., Kurchavyi, G.G. & Veselkin, N.P. Effects of Glycine and GABA on Monosynaptic EPSP in Frog Motoneurons. Neurosci Behav Physi 47, 17–24 (2017). https://doi.org/10.1007/s11055-016-0361-3
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11055-016-0361-3