Stretch receptor-associated expression of α 3 isoform of the na +,k +-atpase in rat peripheral nervous system

• Published in: Neuroscience Vol. 116; no. 4; pp. 1069 - 1080
• Main Authors: Dobretsov, M, Hastings, S.L, Sims, T.J, Stimers, J.R, Romanovsky, D
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 2003
• Subjects: Animals; dorsal root ganglion; Ganglia, Spinal - chemistry; Ganglia, Spinal - enzymology; Gene Expression Regulation - physiology; Guinea Pigs; Isoenzymes - analysis; Isoenzymes - biosynthesis; isoforms of Na +,K +-ATPase; Male; Mechanoreceptors - chemistry; Mechanoreceptors - enzymology; peripheral nervous system; Peripheral Nervous System - chemistry; Peripheral Nervous System - enzymology; Rats; Rats, Sprague-Dawley; skeletal muscle; Sodium-Potassium-Exchanging ATPase - analysis; Sodium-Potassium-Exchanging ATPase - biosynthesis; stretch receptor; PBS; DAB; α 3 Na +,K +-ATPase; dorsal root ganglion; DRG; isoforms of Na +,K +-ATPase; IB4; peripheral nervous system; skeletal muscle; stretch receptor
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(02)00922-3

Expression of the neuronal α 3 isoform of the Na +,K +-ATPase (α 3 Na +,K +-ATPase) was studied in the rat peripheral nervous system using histological and immunohistochemical techniques. Non-uniform expression of the α 3 Na +,K +-ATPase was observed in L5 ventral and dorsal roots, dorsal root ganglion, sciatic nerve and its branches into skeletal muscle. The α 3 Na +,K +-ATPase was not detected in nerve fibers in skin, saphenous and sural nerves. In dorsal root ganglion 12±2% of neurons were immunopositive for α 3 Na +,K +-ATPase and all these neurons were large primary afferents that were not labeled by Griffonia simplicifolia isolectin B4 (marker of small primary sensory neurons). In dorsal and ventral roots 27±3% and 40±3%, respectively, of myelinated axons displayed immunoreactivity for α 3 Na +,K +-ATPase. In contrast to the dorsal roots, strong immunoreactivity in ventral roots was observed only in myelinated axons of small caliber, presumably γ-efferents. In the mixed sciatic nerve α 3 Na +,K +-ATPase was detected in 26±5% of myelinated axons (both small and large caliber). In extensor hallicus proprius and lumbricales hind limb muscles α 3 Na +,K +-ATPase was detected in some intramuscular axons and axonal terminals on intrafusal muscle fibers in the spindle equatorial and polar regions (regions of afferent and efferent innervation of the muscle stretch receptor, respectively). No α 3 Na +,K +-ATPase was found in association with innervation of extrafusal muscle fibers or in tendon-muscle fusion regions. These data demonstrate non-uniform expression of the α 3 isoform of the Na +,K +-ATPase in rat peripheral nervous system and suggest that α 3 Na +,K +-ATPase is specifically expressed in afferent and efferent axons innervating skeletal muscle stretch receptors.