Comparison of antagonist potencies at pre- and post-synaptic GABAB
 receptors at inhibitory synapses in the CA1 region of the rat hippocampus

AbstractDiverse signaling complexes are precisely assembled at the presynaptic active zone for dynamic modulation of synaptic transmission and synaptic plasticity. Presynaptic GABAB-receptors nucleate critical signaling complexes regulating neurotransmitter release at most synapses. However, the molecular mechanisms underlying assembly of GABAB-receptor signaling complexes remain unclear. Here we show that neurexins are required for the localization and function of presynaptic GABAB-receptor signaling complexes. At four model synapses, excitatory calyx of Held synapses in the brainstem, excitatory and inhibitory synapses on hippocampal CA1-region pyramidal neurons, and inhibitory basket cell synapses in the cerebellum, deletion of neurexins rendered neurotransmitter release significantly less sensitive to GABAB-receptor activation. Moreover, deletion of neurexins caused a loss of GABAB-receptors from the presynaptic active zone of the calyx synapse. These findings extend the role of neurexins at the presynaptic active zone to enabling GABAB-receptor signaling, supporting the notion that neurexins function as central organizers of active zone signaling complexes.

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Optically detected long-lasting depolarization of the post-synaptic dendrite membrane upon high frequency and theta burst stimulus in rat hippocampus CA1 region

Neuroscience Research ◽

10.1016/s0168-0102(00)81420-0 ◽

2000 ◽

Vol 38 ◽

pp. S96

Author(s):

T Tominaga

Keyword(s):

High Frequency ◽

Rat Hippocampus ◽

Ca1 Region ◽

Optically Detected ◽

Theta Burst

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Location of Sialoglycoconjugates Containing the Siaα2–3Gal and Siaα2–6Gal Groups in the Rat Hippocampus and the Effect of Aging on Their Expression

Journal of Histochemistry & Cytochemistry ◽

10.1177/002215540104901014 ◽

2001 ◽

Vol 49 (10) ◽

pp. 1311-1319 ◽

Cited By ~ 12

Author(s):

Yuji Sato ◽

Yoshihiro Akimoto ◽

Hayato Kawakami ◽

Hiroshi Hirano ◽

Tamao Endo

Keyword(s):

Electron Microscopy ◽

Plasma Membranes ◽

Pyramidal Cells ◽

Staining Intensity ◽

Rat Hippocampus ◽

Maackia Amurensis ◽

Ca1 Region ◽

Old Rats ◽

Maackia Amurensis Lectin ◽

Stratum Lacunosum Moleculare

The histochemical distribution of sialoglycoconjugates in the CA1 region in the hippocampus formation of 9-week-old rats and 30-month-old rats was examined using electron microscopy in combination with two lectins, Maackia amurensis lectin, specific for Siaα2–3Gal, and Sambucus sieboldiana agglutinin, specific for Siaα2–6Gal. Each lectin stained the plasma membranes of pyramidal cells, indicating that the Siaα2–3Gal and Siaα2–6Gal groups were expressed on their plasma membranes. These lectins also bound to synapses in the stratum lacunosum moleculare. The staining intensity of the lectins in the synapses in these layers was downregulated in the 30-month-old rats. These results indicated that both the Siaα2–3Gal and Siaα2–6Gal groups are expressed on these synapses and that the expression of these sialyl linkages decreases in the aged brain.

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