Neuron specific calcium-binding Protein, calbrain, is involved in memory formation.

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A novel Ca2+-binding protein, termed calbrain, was isolated from a human brain cDNA library. The analysis of deduced amino acid sequence revealed that calbrain contains two putative EF-hand motifs that show significantly high homology to those of the calmodulin(CaM)family rather than two EF-hand protein families. Studies in vitro revealed that calbrain competitively inhibited CaM binding to Ca2+/calmodulin-dependent kinase II(Ki = 129 nM)and reduced its kinase activily and autophosphorylation.Ca2+/calmodulin-dependent protein kinase I(CaM-kinase I)in rat retina was shown to be present in rat retina. Developmental studies revealed that CaM-kinase I expression increased in accordance with postnatal development. Expression of CaM-kinase I in the retinas of rats raised in the complete darkness markedly decreased.CaMK-I was shown to mainly localize in the cytoplasm of the control and LTP-induced neurons, and a significant increase of immunoreactivity was observed in the latter neurons. A part of CaMK-I was found to translocate to the nuclei of LTP-induced hippocampal CA1 neurons.To investigate the mechanism of chronic cell death following postischemic hypothermia, the change of N-methyl-D-aspartate receptor(NMDAR)was examined in the CA1 subfield of the gerbil hippocampus. At 1 week following postischemic hypothermia(32 degrees Cx4 h), all CA1 neurons survived ; however, immunoreactivity of NMDAR1 increased in neuronal perikarya whereas decreased in dendrites in the CA1 neurons. LTP was also significantly depressed at 1 week after hypothermia.Morphological changes of the suprachiasmatic nucleus(SCN)of the hypothalamus were investigated in mice exhibiting intoxication signs of stages 2 or 3 after a short application term of 6% ethanol. Alterations in glial cells and neurons were examined using anti-glial fibrillary acidic protein(GFAP)and short-term ethanol exposure led to strong expression of GFAP-immunoreactivily(GFAP-IR)in the dorsomedial part of the SCN.