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- Title:
Both d- and l-glutamate induce transporter-mediated presynaptic autoinhibition of transmitter release.
- Document type:
- Journal Article; Article
- Author(s):
- Dudel, J
- Abstract:
- In crayfish motor nerve terminals l-glutamate (Glu) is the excitatory transmitter and low l-Glu concentrations exert autoinhibition by inhibiting release of Glu quanta from the terminals. This autoinhibition has been shown to be mediated by binding and transport of l-Glu by Glu transporters in the presynaptic membrane. Activated transporters open an associated Cl(-) channel and inhibit release [J. Dudel & M. Schramm (2003) Eur. J. Neurosci., 18, 902-910]. The excitatory, glutamatergic synaptic transmission is specific for the l-Glu isomer. However, transporters are non-selective for the stereoisomers. It is shown here that low concentrations (5 micro m) of d- as well as l-Glu inhibit quantal release on average to 55 and 68%, respectively. The power of inhibition varies widely at different terminals but the local sensitivity to d-Glu is seen to be the same as that for l-Glu. l-Glutamate has been reported to reduce the mean amplitude of nerve terminal action currents (excitatory nerve terminal currents) by about 10%, presumably due to the opening of Cl(-) channels. Evidence is given that d-Glu also inhibits this by an average of 10% (P < 0.001), as expected if both l- and d-Glu activate a transporter-associated Cl(-) conductance. The results give further support for this novel mechanism of regulation of synaptic strength.
- Journal title abbreviation:
- Eur J Neurosci
- Year:
- 2004
- Journal volume:
- 20
- Journal issue:
- 1
- Pages contribution:
- 161-6
- Language:
- eng
- Fulltext / DOI:
- doi:10.1111/j.1460-9568.2004.03471.x
- Pubmed ID:
- http://view.ncbi.nlm.nih.gov/pubmed/15245488
- Print-ISSN:
- 0953-816X
- TUM Institution:
- Institut für Neurowissenschaften
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