| 1. |
- Bergersen, L H, et al.
(författare)
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Immunogold detection of L-glutamate and D-serine in small synaptic-like microvesicles in adult hippocampal astrocytes.
- 2012
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Ingår i: Cerebral Cortex. - : Oxford University Press. - 1047-3211 .- 1460-2199. ; 22:7, s. 1690-1697
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Tidskriftsartikel (refereegranskat)abstract
- Glutamate and the N-methyl-D-aspartate receptor ligand D-serine are putative gliotransmitters. Here, we show by immunogold cytochemistry of the adult hippocampus that glutamate and D-serine accumulate in synaptic-like microvesicles (SLMVs) in the perisynaptic processes of astrocytes. The estimated concentration of fixed glutamate in the astrocytic SLMVs is comparable to that in synaptic vesicles of excitatory nerve terminals (≈ 45 and ≈ 55 mM, respectively), whereas the D-serine level is about 6 mM. The vesicles are organized in small spaced clusters located near the astrocytic plasma membrane. Endoplasmic reticulum is regularly found in close vicinity to SLMVs, suggesting that astrocytes contain functional nanodomains, where a local Ca(2+) increase can trigger release of glutamate and/or D-serine.
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| 2. |
- Medin, T, et al.
(författare)
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Dopamine D5 receptors are localized at asymmetric synapses in the rat hippocampus.
- 2011
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Ingår i: Neuroscience. - : Elsevier. - 0306-4522 .- 1873-7544. ; 192, s. 164-171
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Tidskriftsartikel (refereegranskat)abstract
- Functional studies indicate that the dopamine D5 receptor is involved in synaptic transmission in the hippocampus. However, previous anatomical studies have detected D5 receptor labelling primarily on the soma and main dendrites of CA1 pyramidal cells and on dendritic spines in monkey but not in rats. In order to get a better understanding of putative dopamine function in the hippocampus, we quantified the D5 receptor immunoreactivity on the pyramidal cell somas and on spines and dendrites in stratum radiatum and stratum oriens in the hippocampal CA1 region of rats by quantitative immunofluorescence and immunogold electron microscopy. The quantitative immunogold results revealed a higher labelling density on dendritic spines, notably at their synaptic membranes, compared to pyramidal cell somas and dendrites. Hence, dopamine could have effects on spines as well as on somas and dendrites. The labelling density was similar on spines in stratum oriens and stratum radiatum, but the presence of labelling varied between the spines within each stratum, indicating that the effect of dopamine could be diverse between different spines.
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