Pocampal (Berninger et al. 1993; Canossa et al. 1997; Finkbeiner et al. 1997; Li et

Pocampal (Berninger et al. 1993; Canossa et al. 1997; Finkbeiner et al. 1997; Li et al. 1998; Marsh and Palfrey 1996) and cortical neurons (Behar et al. 1997; Matsumoto et al. 2001; Mizoguchi and Nabekura 2003; Mizoguchi et al. 2002; Yang and Gu 2005; Zirrgiebel et al. 1995). In contrast, BDNF failed to affect Ca2 levels in cultured cerebellar granule cells (Gaiddon et al. 1996; but see Jia et al. 2007; Numakawa et al. 2001) and in acute slices from visual cortex (Pizzorusso et al. 2000). BDNF also potentiated spontaneous Ca2 oscillations in cultured hippocampal neurons (Numakawa et al. 2002; Sakai et al. 1997); nonetheless, this effect was due to enhanced network activity major to voltagedependent Ca2 influx (Sakai et al. 1997). Also, BDNF elevated Ca2 levels within presynaptic terminals of cultured Xenopus neuromuscular junctions (Boulanger and Poo 1999; Stoop and Poo 1996). Regrettably, almost all published Ca2 imaging research of BDNFCopyright 2007 The American Physiological Society Address for reprint requests along with other correspondence: L. PozzoMiller, Dept. of Neurobiology, SHEL1002, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL Alpha 6 integrin Inhibitors medchemexpress 352942182 ([email protected]).Amaral and PozzoMillerPageactions on intracellular Ca2 levels had been performed with out simultaneous membrane voltage control, producing it hard to differentiate the contribution of voltagegated and receptoroperated Ca2 influx for the observed Ca2 signals. Actually, most research to date conclude that a substantial fraction with the BDNFinduced Ca2 elevations is sensitive to glutamate receptor antagonists (e.g., Yang and Gu 2005). It needs to be noted that dendritic and spine Ca2 elevations induced by BDNF in hippocampal dentate granule cells had been sensitive to voltagegated Ca2 channel blockers (Kovalchuk et al. 2002) and Sapienic acid site normally associated together with the membrane depolarization proposed to be mediated by Nav1.9 channels (Blum et al. 2002; Kafitz et al. 1999). The controversial state of our understanding of BDNF actions on intracellular Ca2 levels prompted us to carry out simultaneous entire cell recording and microfluorometric imaging in voltageclamped neurons. We present evidence that localized BDNF application to apical dendrites of CA1 pyramidal neurons in hippocampal slice cultures evoked transient elevations in intracellular Ca2 concentration, which are independent of voltagegated Ca2 channels and NmethylDaspartate (NMDA) receptors. These Ca2 signals were always associated with IBDNF, a slow and sustained nonselective cationic existing mediated by TRPC3 channels (Amaral and PozzoMiller 2007; Li et al. 1999). BDNFinduced Ca2 elevations needed functional Trk and IP3 receptors, complete intracellular Ca2 stores, also as extracellular Ca2, suggesting the involvement of TRPC channels. Indeed, the TRPC channel inhibitor SKF96365 prevented BDNFinduced Ca2 elevations and also the connected IBDNF. Therefore TRPC channels emerge as novel mediators of BDNFinduced intracellular Ca2 elevations in hippocampal pyramidal neurons.NIHPA Author Manuscript NIHPA Author Manuscript NIHPA Author ManuscriptMETHODSOrganotypic slice culture All procedures performed on experimental animals adhered to national and international suggestions for the ethical use of analysis animals and had been approved by the Institutional Animal Care and Use Committee (IACUC) with the University of Alabama at Birmingham. Briefly, hippocampi had been dissected from anesthetized postnatal day 71 Sprague Dawley rats (Harlan, Indianapoli.