Novel markers for OLM interneurons in the hippocampus

• Autor(a) principal: Mikulovic, Sanja
• Data de Publicação: 2015
• Outros Autores: Restrepo, C. Ernesto, Hilscher, Markus M., Kullander, Klas, Leão, Richardson Naves
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/jspui/handle/123456789/23188
• topic: interneuron; Oriens-lacunosum moleculare; somatostatin; hippocampus; Chrna2

Oriens-lacunosum moleculare (OLM) cells are a major subclass of hippocampal interneurons involved in controlling synaptic plasticity in Shaffer collateral synapses (Leão et al., 2012) and electrogenesis in pyramidal cell (PC) dendrites (Lovett-Barron et al., 2012). Their firing phase is locked with theta oscillations, which imply a role for these cells in theta rhythmogenesis (Klausberger and Somogyi, 2008; Forro et al., 2015). OLM interneurons also appear to be key in the pathophysiology of epilepsy (Dugladze et al., 2007) and is the most vulnerable interneuron population in models of epilepsy (Dinocourt et al., 2003). Somatostatin has been frequently used as a molecular marker for identification of OLM cells (Forro et al., 2015). Two recent studies suggest that the OLM cell population is heterogeneous. First, the expression of cholinergic receptor, nicotinic, alpha polypeptide 2 (Chrna2) seems to be restricted to OLM interneurons neurons of CA1 (Leão et al., 2012). Second, a subset of OLM interneurons that expresses the 5HT3a receptor is derived from the caudal ganglionic eminence and do not entrain to gamma oscillations. In contrast, OLM interneurons derived from the medial ganglionic eminence partially phase lock to in vitro gamma oscillations and do not express 5HT3a receptors (Chittajallu et al., 2013). Further, other dendritic targeting interneurons in the hippocampus also express somatostatin (Lovett-Barron et al., 2014). Hence, functional studies of OLM cell in hippocampal function have been targeting a relatively heterogenous cell population.