Functional Characterization of Intrinsic Cholinergic Interneurons in the Cortex

Abstract

Acetylcholine is a major neurotransmitter that modulates cortical functions. In addition to basal forebrain neurons that give rise to the principal cholinergic input into the cortex, a second source constituted by intrinsic cholinergic interneurons has been identified. Although these cells have been characterized anatomically, little is known about their functional role in cortical microcircuits. The paucity of this cell population has been a major hindrance for detailed electrophysiological investigations. To facilitate functional studies, we generated transgenic mice that express enhanced green fluorescent protein (

Bitter triggers acetylcholine release from polymodal urethral chemosensory cells and bladder reflexes

“…Two independently generated ChAT (BAC) -eGFP mice were provided by M. Kotlikoff (Cornell University), and H. Monyer (University of Heidelberg) (10,11). Tg(Chrna3-EGFP)BZ135Gsat mice with eGFP driven by the nAChR α3β4α5 cluster were provided by I. Ibanez-Tallon (MDC Molecular Medicine) (24).…”

5-HT3AReceptor-Bearing White Matter Interstitial GABAergic Interneurons Are Functionally Integrated into Cortical and Subcortical Networks

“…The analysis of electrophysiological properties was performed essentially as described previously (von Engelhardt et al, 2007). Hyperpolarizing and depolarizing current pulses (1 s) were applied to calculate input resistance and threshold potential.…”

Illuminating Cholinergic Microcircuits in the Neocortex: Figure 1.

“…Because ChAT is expressed in some cortical interneurons (Bayraktar et al, 1997;Cauli et al, 1997) Next, the authors examined the morphological and electrophysiological properties as well as the synaptic connectivity of bipolar EGFPϩ cells. These cells typically exhibited vertically oriented dendritic and axonal arbors with axons extending mainly to layers IV and V [von Engelhardt et al (2007), their Fig. 6 (http://www.jneurosci.org/cgi/content/ full/27/21/5633/F6)].…”

“…Specifically, activation of EGFPϩ neurons produced a small but significant increase in the frequency of spontaneous EPSCs (sEPSC) in pyramidal cells during EGFPϩ cell firing [von Engelhardt et al (2007), their Fig. 8 (http:// www.jneurosci.org/cgi/content/full/27/ 21/5633/F8)].…”

“…Thus, intracortical cholinergic neurons may play a crucial role in the integration of subcortical and intracortical pathways. The transgenic mouse model developed by von Engelhardt et al (2007) provides a powerful tool to study the role of ChATϩ interneurons in cortical networks. Clearly, additional work is necessary to establish such an integrative role of intracortical cholinergic interneurons; however, the findings of von Engelhardt et al (2007) represent a stepping stone in illuminating the cholinergic functions in cortical information processing.…”