NMDA receptors hippocampal, function

The regulation of intracellular neuronal Ca2+ is of high functional significance. Ca2+-dependent neurotransmitter release is reduced by the Ca2+/ATPase pump (Fossier et al. 1993). Although immediate Ca2+ currents are mediated by ionotropic glutamate receptors (i.e., NMDA) in hippocampal neurons, a sizable portion of neurons show delayed Ca2+ increases from intracellular pools (Miller et al. 1996). These delayed changes were synaptically mediated and dependent upon endosomal Ca2+/ATPase. 

We demonstrated for the first time that crocin selectively antagonizes the inhibitory effect of ethanol on NMDA-receptor-mediated responses in hippocampal neurons. This action of crocin may underlie the antagonism against ethanol-induced memory impairment. Crocin should be useful as a new pharmacological tool for studying the mechanism of ethanol inhibition of NMDA receptor functions. 

Okabe S., Vicario-Abejon C., Segal M., and McKay R. D. (1998). Survival and synaptogenesis of hippocampal neurons without NMDA receptor function in culture. Eur. J. Neurosci. 10 2192-2198. 

Risso F, Grilli M, Parodi M et al (2004) Nicotine exerts a permissive role on NMDA receptor function in hippocampal noradrenergic terminals. Neuropharmacology 47 65-71 Rodrigues RJ, Alfaro TM, Rebola N et al (2005) Co-localization and functional interaction between adenosine A2A and metabotropic group 5 receptors in glutamatergic nerve terminals of the rat striatum. J Neurochem 92 433 41... 

An interesting aspect of FGF-2 function is its reported ability to affect the expression and function of ion channels. Treatment of PC 12 cells with FGF-2 for several days induces increases in sodium channel density (Pollock et al., 1990) and increased calcium currents (Rane and Pollock, 1994). FGF-2 may act even more rapidly, as indicated by its enhancement of NMDA receptor-mediated calcium influx into hippocampal cells (Abe and Saito, 1992), its stimulation of light responses in photoreceptors (Schmidt et al., 1995) and its ability to enhance long-term potentiation in hippocampal slices after short-term treatments (20 min) (Terlau and Seifert, 1990), an effect also observed with FGF-1 (Sasaki et al., 1994b). 

Mattson, M.P., Kumar, K.N., Wang, H., Cheng, B. and Michaelis, E.K. (1993c) Basic FGF regulates the expression of a functional 71-kDa NMDA receptor protein that mediates calcium influx and neurotoxicity in hippocampal neurons. J. Neurosci. 13 4575-4588. 

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