Target‐determined expression of α₃ isoform of the Na⁺,K⁺‐ATPase in the somatic nervous system of rat

Abstract

Factors that determine the differential expression of isoforms of Na(+),K(+)-ATPase in the nervous system of vertebrates are not understood. To address this question we studied the expression of alpha(3) Na(+),K(+)-ATPase in the L5 dorsal root ganglia (DRG) of developing rat, the normal adult rat, and the adult rat after peripheral axotomy. During development, the first alpha(3) Na(+),K(+)-ATPase-positive DRG neurons appear by embryonic day 21. At birth, the L5 DRG have a full complement (14 +/- 2%) of these neurons. By 15 days after sciatic nerve transection in adult rat, the number of alpha(3) Na(+),K(+)-ATPase-positive DRG neurons and small myelinated L5 ventral root axons decreases to about 35% of control counts. These results combined with data from the literature suggest that the expression of alpha(3) Na(+),K(+)-ATPase by rat somatic neurons is determined by target-muscle spindle-derived factors.

Phylogenetic preservation of α3 Na+,K+‐ATPase distribution in vertebrate peripheral nervous systems

“…1E). This value is similar to that measured previously for adult rat lumbar DRG (Dobretsov et al, 1999b(Dobretsov et al, , 2003Romanovsky et al, 2005). In frogs, only 5% Ϯ 2% of DRG neurons (nine ganglia) had detectable membrane ␣ 3 Na ϩ ,K ϩ -ATPase.…”

“…The hypothesis that stretch receptors uniquely express ␣ 3 Na ϩ ,K ϩ -ATPase in the PNS is based on three observations (Romanovsky et al, 2005). First, in rat DRG, all ␣ 3 Na ϩ ,K ϩ -ATPase-positive neurons are encompassed in the population of large neurons, which, in rats, mice, and birds, also encompasses functionally defined lowthreshold mechanoreceptors, including stretch receptor afferents (Lawson, 1992).…”

“Clock-scan” protocol for image analysis

“…Images of dissociated and cultured or paraffin-embedded and sectioned rat DRG neurons used in this work were collected in the course of previous studies in our laboratory involving the peripheral nervous system of vertebrates (1,2,4,10). All the examples shown are of cells that were labeled for the ␣ 3 isoform of Na ϩ ,K ϩ -ATPase with isozyme-specific primary antibodies and rhodamine-or biotintagged secondary antibodies.…”

Age-dependent decline in density of human nerve and spinal ganglia neurons expressing the α3 isoform of Na/K-ATPase

“…Upon receipt in the laboratory, samples were cleaned of fat tissue, inspected for integrity, trimmed, post-fixed in 4% formaldehyde for 5-7 days at 4 ° C and then processed for immunostaining using an established protocol of our laboratory (Romanovsky et al, 2005). In studies of tibial nerve samples, several sequential 5-μm thick cross-sections were cut and each immunostained for α3NKA and then stained with haematoxylin.…”

“…This antibody recognizes the intracellular isoform-specific domain of the α3 subunit of NKA, and has been previously extensively characterized, including through immunochemistry experiments using higher primate and human tissue by our and by other groups (Blaustein and Juhaszova, 1997; Dobretsov et al, 2003; Dobretsov et al, 1999; Edwards et al, 2013; Romanovsky et al, 2005; Romanovsky et al, 2007; Shyjan and Levenson, 1989). Biotinylated secondary antibodies were obtained from Jackson Laboratories (West Grove, PA).…”