Presynaptic actions of glutamate receptor agonists in the CA1 region of rat hippocampus in vitro

Shew, T.; Morishita, Wade; Sastry, B.R.

doi:10.1016/0014-2999(95)00371-q

Cited by 9 publications

(2 citation statements)

References 17 publications

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“…Several studies in other brain regions also indicate that enkephalin, acting at presynaptic opioid receptors on glutamatergic terminals, may inhibit the release of glutamate by suppressing calcium entry into axon terminals (Hori et al, 1992;Wilding et al, 1995). Conversely, NMDAR1 is believed to presynaptically autoregulate glutamate release through increased calcium entry (Sherman et al, 1992;Shew et al, 1995). These findings support the hypothesis that MOR and NMDAR1 receptor agonists have opposing effects in mediating presynaptic calcium influx in the same glutamatergic terminals.…”

Section: Mor-and Nmdar1-li Are Colocalized In Terminalsmentioning

confidence: 59%

Dual Ultrastructural Localization of μ-Opioid Receptors and NMDA-Type Glutamate Receptors in the Shell of the Rat Nucleus Accumbens

1997

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The effectiveness of NMDA antagonists in modulating the motor and motivational effects of opiates is attributed, in part, to functional associations involving NMDA receptors and -opioid receptors (MORs) in the shell of the nucleus accumbens (Acb). To determine the subcellular sites for potential functional interactions between opiate ligands and NMDA receptors in this region, we examined the ultrastructural localization of antipeptide antisera against MOR and the R1 subunit of the NMDA receptor in the Acb shell of the adult rat brain. MOR-like immunoreactivity (MOR-LI) was seen primarily in dendrites, whereas NMDAR1-like immunoreactivity (NMDAR1-LI) was detected more often in axon terminals forming asymmetric synapses. In these profiles, MOR labeling was localized mainly to extrasynaptic plasma membranes, whereas NMDAR1-LI was associated with both synaptic and extrasynaptic sites. Of 307 MOR-labeled processes, 17.9% of the dendrites and 9.4% of the axon terminals also contained NMDAR1-LI. In addition, 24.7% of the dendrites containing only MOR-LI were apposed to NMDAR1-labeled axons or terminals. We conclude that in the shell of the Acb, the output of single neurons can be dually modulated by (1) activation of MOR and NMDA receptors in the same dendrites or (2) combined activation of presynaptic NMDA receptors in afferents contacting dendrites containing MOR. In addition, the colocalization of MOR and NMDAR1 in certain axon terminals in the Acb suggests their dual involvement in the presynaptic release of neurotransmitters in this region.

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Section: Mor-and Nmdar1-li Are Colocalized In Terminalsmentioning

confidence: 59%

Dual Ultrastructural Localization of μ-Opioid Receptors and NMDA-Type Glutamate Receptors in the Shell of the Rat Nucleus Accumbens

1997

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“…These often formed asymmetric or excitatory type synapses, suggesting the autoregulation of glutamate release through activation of NR1 receptors. NMDA activation is believed to presynaptically autoregulate glutamate release through increased calcium entry (Shew et al, 1995). Some axon terminals that contained NR1 immunoreactivity also exhibited MOR, suggesting that NR1 and MOR ligands may modulate presynaptically the release of other transmitters onto LC dendrites.…”

Section: Discussionmentioning

confidence: 99%

Evidence for coexistence of enkephalin and glutamate in axon terminals and cellular sites for functional interactions of their receptors in the rat locus coeruleus

et al. 2000

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Frequent colocalization of mu opioid and NMDA-type glutamate receptors at postsynaptic sites in periaqueductal gray neurons

1999

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Presynaptic actions of glutamate receptor agonists in the CA1 region of rat hippocampus in vitro

Cited by 9 publications

References 17 publications

Dual Ultrastructural Localization of μ-Opioid Receptors and NMDA-Type Glutamate Receptors in the Shell of the Rat Nucleus Accumbens

Dual Ultrastructural Localization of μ-Opioid Receptors and NMDA-Type Glutamate Receptors in the Shell of the Rat Nucleus Accumbens

Evidence for coexistence of enkephalin and glutamate in axon terminals and cellular sites for functional interactions of their receptors in the rat locus coeruleus

Frequent colocalization of mu opioid and NMDA-type glutamate receptors at postsynaptic sites in periaqueductal gray neurons

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