Neurogliaform Neurons Form a Novel Inhibitory Network in the Hippocampal CA1 Area

Abstract

We studied neurogliaform neurons in the stratum lacunosum moleculare of the CA1 hippocampal area. These interneurons have short stellate dendrites and an extensive axonal arbor mainly located in the stratum lacunosum moleculare. Single-cell reverse transcription-PCR showed that these neurons were GABAergic and that the majority expressed mRNA for neuropeptide Y. Most neurogliaform neurons tested were immunoreactive for ␣-actinin-2, and many stratum lacunosum moleculare interneurons coexpressed ␣-actinin-2 and neuropeptide Y. Neurogliaform neurons received monosynaptic, DNQX-sensitive excitatory input from the perforant path, and 40 Hz stimulation of this input evoked EPSCs displaying either depression or initial facilitation, followed by depression. Paired recordings performed between neurogliaform neurons showed that 85% of pairs were electrically connected and 70% were also connected via

Entorhinal–hippocampal neuronal circuits bridge temporally discontiguous events

“…This is consistent with previous studies pointing to the existence of a feedforward inhibitory circuit arising from direct entorhinal inputs into CA1 (Remondes and Schuman 2002). SL-INs are connected by gap junctions (Price et al 2005). Thus, activation of Island cell axons can evoke a depolarizing response broadly among SL-INs, which may propagate through gap junctions and amplify the effect of Island cell inputs to suppress MECIII input to CA1 distal dendrites.…”

β‐adrenergic receptors are differentially expressed in distinct interneuron subtypes in the rat hippocampus

“…aform cells (Price et al, 2005) and were found in high numbers in the hilus and subgranular zone of the dentate gyrus and CA1 stratum pyramidale and stratum oriens (Fig. 6A, Table 2), as previously reported (Freund and Buzsaki, 1996).…”

Neurodevelopment, GABA System Dysfunction, and Schizophrenia

“…Another type of basket cells, containing CCK, also form perisomatic contacts onto pyramidal cells; however, they are distinguished from the PV þ variety by their slower, accommodating firing patterns (Hefft and Jonas, 2005) that integrate neuromodulatory information with faster network activity (Freund, 2003;Varga et al, 2009). Interconnected networks of NPY þ neurogliaform cells mediate regional tonic inhibition through extrasynaptic volume transmission in multiple cortical and subcortical regions (Manko et al, 2012;Olah et al, 2009;Price et al, 2005). Martinotti cells, containing CR, CB, SST, NPY, and/or CCK, span both cortical lamina and cortical columns and synapse onto pyramidal cell tuft dendrites in layer I (Markram et al, 2004).…”