Regional and temporal expression of sodium channel messenger RNAs in the rat brain during development

Abstract

The distribution of mRNA expression for three types of voltage gated neuronal sodium-channels was studied in the rat brain at different developmental stages (embryonal day E18, postnatal day P5 and adult). With the in-situ hybridization technique, using synthetic DNA-oligomer probes, pronounced regional and temporal variations in the expression levels of the different channel subtypes could be detected. In comparison with types I and III, sodium channel II mRNA was the most abundant subtype at all developmental stages. Maximal expression of sodium channel II mRNA was seen at P5 in virtually all parts of the grey matter, except for the cerebellum. In adult rat brain in contrast, sodium channel II mRNA levels were maximal in the granular layer of the cerebellum, whereas in all other regions expression had decreased to roughly 50% of postnatal levels. Na channel I expression was virtually absent at E18 and showed highest levels at P5, with maxima in the caudate nucleus and hippocampus. In the adult brain, expression of Na-channel I was nearly absent in the neocortex, but well detectable in the cerebellum and, at lower levels in the striatum and thalamus. Sodium channel III was mainly expressed at the embryonal stage and showed a decrease to very low levels with little regional preferences in the adult.

Voltage-Gated Sodium Channels in Cerebellar Purkinje Cells of Mormyrid Fish

“…In our immunohistochemical experiments, however, we did not see staining of granule cell somata or axons above background levels. The expression of Na v 1.2 in mammalian Purkinje cells has been debated (Black et al 1994;Felts et al 1997; but see Brysch et al 1991;Gong et al 1999; for review see Schaller and Caldwell 2003). Our data indicate that Na v 1.2 is expressed in somata and dendrites of rat Purkinje cells and thus support the findings of Waxman and colleagues (Black et al 1994;Felts et al 1997).…”

“…Mammalian Purkinje cells express Na ϩ channel ␣-subunits Na v 1.1 and Na v 1.6 in both soma and dendrites (Gong et al 1999;Schaller and Caldwell 2003). Reports on the expression of Na v 1.2 in Purkinje cells are conflicting (Black et al 1994;Felts et al 1997; but see Brysch et al 1991;Gong et al 1999).…”

Distribution of voltage-gated sodium channel ?-subunit and ?-subunit mRNAs in human hippocampal formation, cortex, and cerebellum

“…3 Our experiments have highlighted the possible differential expression of type III compared with that seen in the rat CNS. In rat, the type III channel is regarded mainly as an embryonic channel, because it has very limited distribution in the adult brain (Beckh et al, 1989;Brysch et al, 1991;Felts et al, 1997). Our in situ hybridisation data suggest that, in the human adult brain, type III mRNA is expressed at detectable levels throughout two of the three regions examined (cerebral cortex and parahippocampal gyrus) and also is expressed within areas of the third region examined (cerebellum).…”

“…Sodium channel ␣ and ␤ subunits show a defined temporal and spatial distribution in the rat central nervous system (CNS) revealed by immunoprecipitation (Gordon et al, 1987), Northern blot analysis (Beckh et al, 1989), reverse transcriptase-polymerase chain reaction (RT-PCR; Yarowsky et al, 1991), in situ hybridisation (Brysch et al, 1991;Furuyama et al, 1993;Black et al, 1994;Schaller et al, 1995;Felts et al, 1997;Gastaldi et al, 1997Gastaldi et al, , 1998Levy-Mozziconacci et al, 1998), and immunohistochemistry (Westenbroek et al, 1989). These studies show that the expression of sodium channel type I begins to increase after birth and, in the adult, is highest in caudal regions (e.g., colliculus and medulla pons) of the CNS.…”

Sodium Channel Expression: A Dynamic Process in Neurons and Non-Neuronal Cells

“…It has yet to be established whether the expression of the sodium channel isoforms in the (3-cells is dcvelopmentally regulated. However, in the nervous system, sodium channel III is generally considered to be an embryonic form of sodium channel (4,13], or one that is re-expressed in adult neurons following injury [45,99]. Osteoblasts, which have been shown to express TTXsensitive, voltage-sensitive sodium current [18], also express rat brain type sodium channels in the embryonic Sodium Channels in Neurons and Non-Neuronal Cells rat.…”