Abstract
The effects of the N-methyl-D-aspartate (NMDA) receptor antagonist, D-2-amino-5-phosphonovaleric acid (D-APV), and other excitatory amino acid antagonists, were studied on CA1 pyramidal neurones treated with picrotoxin or bicuculline to reduce synaptic inhibition mediated by gamma-aminobutyric acid (GABA). Under these conditions epileptiform burst firing is readily produced by orthodromic stimulation of the pyramidal cell population. D-APV reduced the plateau amplitude and duration of the depolarization underlying evoked and spontaneous bursts without affecting membrane potential, input resistance or the ability of the cell to fire a Ca2+ spike or a short train of Na+ spikes. A late component of the subthreshold excitatory post-synaptic potential (e.p.s.p.) was voltage dependent, being reduced in amplitude on membrane hyperpolarization. D-APV selectively removed this component of the e.p.s.p. in disinhibited slices. In contrast, in the absence of GABA antagonists, D-APV had no noticeable effect on the e.p.s.p. as studied with field potential recordings. The concentration-response relationship of the inhibitory effect of D-APV and L-APV on population spike bursts was studied. The action of APV was highly stereoselective; the EC50 of D-APV was approximately 700 nM, whereas a similar inhibition required 540 microM-L-APV. A number of other excitatory amino acid antagonists were tested at a fixed concentration (100 microM). Among them, the quisqualate antagonist gamma-D-glutamylaminomethyl sulphonic acid was ineffective against epileptiform bursts. In the low nanomolar concentration range both D- and L-APV potentiated bursting. These results suggest that in the absence of GABAergic inhibition, a significant component of the slow depolarization underlying burst firing is voltage dependent, synaptic in origin and mediated by NMDA receptors. We propose that, under normal (non-epileptic) physiological conditions, the balance between synaptic inhibition mediated by GABA receptors and synaptic excitation mediated by NMDA receptors may modulate the excitability of pyramidal cell dendrites.
Full text
PDF














Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Coan E. J., Collingridge G. L. Magnesium ions block an N-methyl-D-aspartate receptor-mediated component of synaptic transmission in rat hippocampus. Neurosci Lett. 1985 Jan 7;53(1):21–26. doi: 10.1016/0304-3940(85)90091-6. [DOI] [PubMed] [Google Scholar]
- Collingridge G. L., Kehl S. J., McLennan H. Excitatory amino acids in synaptic transmission in the Schaffer collateral-commissural pathway of the rat hippocampus. J Physiol. 1983 Jan;334:33–46. doi: 10.1113/jphysiol.1983.sp014478. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Corradetti R., King A. E., Nistri A., Rovira C., Sivilotti L. Pharmacological characterization of D-aminophosphonovaleric acid antagonism of amino acid and synaptically evoked excitations on frog motoneurones in vitro: an intracellular study. Br J Pharmacol. 1985 Sep;86(1):19–25. doi: 10.1111/j.1476-5381.1985.tb09430.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Croucher M. J., Collins J. F., Meldrum B. S. Anticonvulsant action of excitatory amino acid antagonists. Science. 1982 May 21;216(4548):899–901. doi: 10.1126/science.7079744. [DOI] [PubMed] [Google Scholar]
- Crunelli V., Forda S., Kelly J. S. Blockade of amino acid-induced depolarizations and inhibition of excitatory post-synaptic potentials in rat dentate gyrus. J Physiol. 1983 Aug;341:627–640. doi: 10.1113/jphysiol.1983.sp014829. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DAHLBOM R., MISORNY A., TRUANT A. P. QUATERNARY DERIVATIVES OF AMINOACYLANILINES. I. Acta Pharm Suec. 1965 Jun;2:213–218. [PubMed] [Google Scholar]
- Davies J., Francis A. A., Jones A. W., Watkins J. C. 2-Amino-5-phosphonovalerate (2APV), a potent and selective antagonist of amino acid-induced and synaptic excitation. Neurosci Lett. 1981 Jan 1;21(1):77–81. doi: 10.1016/0304-3940(81)90061-6. [DOI] [PubMed] [Google Scholar]
- Davies J., Watkins J. C. Actions of D and L forms of 2-amino-5-phosphonovalerate and 2-amino-4-phosphonobutyrate in the cat spinal cord. Brain Res. 1982 Mar 11;235(2):378–386. doi: 10.1016/0006-8993(82)91017-4. [DOI] [PubMed] [Google Scholar]
- Dingledine R. N-methyl aspartate activates voltage-dependent calcium conductance in rat hippocampal pyramidal cells. J Physiol. 1983 Oct;343:385–405. doi: 10.1113/jphysiol.1983.sp014899. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans R. H., Francis A. A., Jones A. W., Smith D. A., Watkins J. C. The effects of a series of omega-phosphonic alpha-carboxylic amino acids on electrically evoked and excitant amino acid-induced responses in isolated spinal cord preparations. Br J Pharmacol. 1982 Jan;75(1):65–75. doi: 10.1111/j.1476-5381.1982.tb08758.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Flatman J. A., Schwindt P. C., Crill W. E., Stafstrom C. E. Multiple actions of N-methyl-D-aspartate on cat neocortical neurons in vitro. Brain Res. 1983 Apr 25;266(1):169–173. doi: 10.1016/0006-8993(83)91323-9. [DOI] [PubMed] [Google Scholar]
- Greenamyre J. T., Olson J. M., Penney J. B., Jr, Young A. B. Autoradiographic characterization of N-methyl-D-aspartate-, quisqualate- and kainate-sensitive glutamate binding sites. J Pharmacol Exp Ther. 1985 Apr;233(1):254–263. [PubMed] [Google Scholar]
- Hablitz J. J. Conductance changes induced by DL-homocysteic acid and N-methyl-DL-aspartic acid in hippocampal neurons. Brain Res. 1982 Sep 9;247(1):149–153. doi: 10.1016/0006-8993(82)91040-x. [DOI] [PubMed] [Google Scholar]
- Hablitz J. J., Langmoen I. A. N-methyl-D-aspartate receptor antagonists reduce synaptic excitation in the hippocampus. J Neurosci. 1986 Jan;6(1):102–106. doi: 10.1523/JNEUROSCI.06-01-00102.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Herron C. E., Williamson R., Collingridge G. L. A selective N-methyl-D-aspartate antagonist depresses epileptiform activity in rat hippocampal slices. Neurosci Lett. 1985 Nov 11;61(3):255–260. doi: 10.1016/0304-3940(85)90473-2. [DOI] [PubMed] [Google Scholar]
- Ikeda H., Sheardown M. J. Aspartate may be an excitatory transmitter mediating visual excitation of "sustained" but not "transient" cells in the cat retina: iontophoretic studies in vivo. Neuroscience. 1982 Jan;7(1):25–36. doi: 10.1016/0306-4522(82)90150-6. [DOI] [PubMed] [Google Scholar]
- Johnston D., Brown T. H. Giant synaptic potential hypothesis for epileptiform activity. Science. 1981 Jan 16;211(4479):294–297. doi: 10.1126/science.7444469. [DOI] [PubMed] [Google Scholar]
- Jones A. W., Smith D. A., Watkins J. C. Structure-activity relations of dipeptide antagonists of excitatory amino acids. Neuroscience. 1984 Oct;13(2):573–581. doi: 10.1016/0306-4522(84)90250-1. [DOI] [PubMed] [Google Scholar]
- King G. L., Knox J. J., Dingledine R. Reduction of inhibition by a benzodiazepine antagonist, Ro15-1788, in the rat hippocampal slice. Neuroscience. 1985 Jun;15(2):371–378. doi: 10.1016/0306-4522(85)90219-2. [DOI] [PubMed] [Google Scholar]
- Koerner J. F., Cotman C. W. Response of Schaffer collateral-CA 1 pyramidal cell synapses of the hippocampus to analogues of acidic amino acids. Brain Res. 1982 Nov 11;251(1):105–115. doi: 10.1016/0006-8993(82)91278-1. [DOI] [PubMed] [Google Scholar]
- MacDonald J. F., Porietis A. V., Wojtowicz J. M. L-Aspartic acid induces a region of negative slope conductance in the current-voltage relationship of cultured spinal cord neurons. Brain Res. 1982 Apr 8;237(1):248–253. doi: 10.1016/0006-8993(82)90575-3. [DOI] [PubMed] [Google Scholar]
- Mayer M. L., Westbrook G. L., Guthrie P. B. Voltage-dependent block by Mg2+ of NMDA responses in spinal cord neurones. Nature. 1984 May 17;309(5965):261–263. doi: 10.1038/309261a0. [DOI] [PubMed] [Google Scholar]
- McCarren M., Alger B. E. Use-dependent depression of IPSPs in rat hippocampal pyramidal cells in vitro. J Neurophysiol. 1985 Feb;53(2):557–571. doi: 10.1152/jn.1985.53.2.557. [DOI] [PubMed] [Google Scholar]
- Miles R., Wong R. K., Traub R. D. Synchronized afterdischarges in the hippocampus: contribution of local synaptic interactions. Neuroscience. 1984 Aug;12(4):1179–1189. doi: 10.1016/0306-4522(84)90012-5. [DOI] [PubMed] [Google Scholar]
- Miller J. P., Rall W., Rinzel J. Synaptic amplification by active membrane in dendritic spines. Brain Res. 1985 Jan 28;325(1-2):325–330. doi: 10.1016/0006-8993(85)90333-6. [DOI] [PubMed] [Google Scholar]
- Nicoll R. A., Alger B. E. A simple chamber for recording from submerged brain slices. J Neurosci Methods. 1981 Aug;4(2):153–156. doi: 10.1016/0165-0270(81)90049-2. [DOI] [PubMed] [Google Scholar]
- Nowak L., Bregestovski P., Ascher P., Herbet A., Prochiantz A. Magnesium gates glutamate-activated channels in mouse central neurones. Nature. 1984 Feb 2;307(5950):462–465. doi: 10.1038/307462a0. [DOI] [PubMed] [Google Scholar]
- Perkel D. H., Perkel D. J. Dendritic spines: role of active membrane in modulating synaptic efficacy. Brain Res. 1985 Jan 28;325(1-2):331–335. doi: 10.1016/0006-8993(85)90334-8. [DOI] [PubMed] [Google Scholar]
- Ryan G. P., Hackman J. C., Davidoff R. A. Spinal seizures and excitatory amino acid-mediated synaptic transmission. Neurosci Lett. 1984 Feb 10;44(2):161–166. doi: 10.1016/0304-3940(84)90075-2. [DOI] [PubMed] [Google Scholar]
- Thomson A. M., West D. C., Lodge D. An N-methylaspartate receptor-mediated synapse in rat cerebral cortex: a site of action of ketamine? Nature. 1985 Feb 7;313(6002):479–481. doi: 10.1038/313479a0. [DOI] [PubMed] [Google Scholar]
- Valentino R. J., Dingledine R. Pharmacological characterization of opioid effects in the rat hippocampal slice. J Pharmacol Exp Ther. 1982 Nov;223(2):502–509. [PubMed] [Google Scholar]
- Wigström H., Gustafsson B. Facilitation of hippocampal long-lasting potentiation by GABA antagonists. Acta Physiol Scand. 1985 Sep;125(1):159–172. doi: 10.1111/j.1748-1716.1985.tb07703.x. [DOI] [PubMed] [Google Scholar]