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alpha7 nicotinic acetylcholine receptors on GABAergic interneurons evoke dendritic and somatic inhibition of hippocampal neurons.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Buhler, Amber V. |
| Copyright Year | 2002 |
| Abstract | GABAergic interneurons in the hippocampus express high levels of alpha7 nicotinic acetylcholine receptors, but because of the diverse roles played by hippocampal interneurons, the impact of activation of these receptors on hippocampal output neurons (i.e., CA1 pyramidal cells) is unclear. Activation of hippocampal interneurons could directly inhibit pyramidal neuron activity but could also produce inhibition of other GABAergic cells leading to disinhibition of pyramidal cells. To characterize the inhibitory circuits activated by these receptors, exogenous acetylcholine was applied directly to CA1 interneurons in hippocampal slices, and the resulting postsynaptic responses were recorded from pyramidal neurons or interneurons. Inhibitory currents mediated by GABA(A) receptors were observed in 27/131 interneuron/pyramidal cell pairs, but no instances of disinhibition of spontaneous inhibitory events or GABA(B) receptor-mediated responses were observed. Two populations of bicuculline-sensitive GABA(A) receptor-mediated currents could be distinguished based on their kinetics and amplitude. Anatomical reconstructions of the interneurons in a subset of connected pairs support the hypothesis that these two populations correspond to inhibitory synapses located either on the somata or dendrites of pyramidal cells. In 11 interneuron/interneuron cell pairs, one presynaptic neuron was observed that produced strong inhibitory currents in several nearby interneurons, suggesting that disinhibition of pyramidal neurons may also occur. All three types of inhibitory responses (somatic-pyramidal, dendritic-pyramidal, and interneuronal) were blocked by the alpha7 receptor-selective antagonist methyllycaconitine. These data suggest activation of these functionally distinct circuits by alpha7 receptors results in significant inhibition of both hippocampal pyramidal neurons as well as interneurons. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://commons.pacificu.edu/cgi/viewcontent.cgi?article=1021&context=phrmfac&httpsredir=1&referer= |
| Alternate Webpage(s) | http://jn.physiology.org/content/jn/87/1/548.full.pdf |
| Alternate Webpage(s) | http://commons.pacificu.edu/cgi/viewcontent.cgi?article=1021&context=phrmfac |
| PubMed reference number | 11784770v1 |
| Volume Number | 87 |
| Issue Number | 1 |
| Journal | Journal of neurophysiology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Acetylcholine Bicuculline CA1 field Cholinergic Receptors Dendrites Diploid Cell Hippocampus (Brain) Interneurons Kinetics (discipline) Neurons Nicotinic Receptors Pyramidal Cells Social disinhibition Subgroup Synapses gamma-Aminobutyric Acid methyllycaconitine |
| Content Type | Text |
| Resource Type | Article |
