Immunostaining for the α3 isoform of the Na⁺/K⁺-ATPase is selective for functionally identified muscle spindle afferents in vivo | Macquarie University ResearchOnline

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Immunostaining for the α3 isoform of the Na⁺/K⁺-ATPase is selective for functionally identified muscle spindle afferents in vivo

Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/118044

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Title: Immunostaining for the α3 isoform of the Na⁺/K⁺-ATPase is selective for functionally identified muscle spindle afferents in vivo
Related: Journal of physiology, Vol. 588, Issue 21 (2010), p.4131-4143
DOI: 10.1113/jphysiol.2010.196386
Publisher: The Physiology Society
Date: 2010
FoR/RFCD Code(s): 060600 Physiology 111600 Medical Physiology
Author/Creator: Parekh, A
Author/Creator: Campbell, A. J. M
Author/Creator: Djouhri, L
Author/Creator: Fang, X
Author/Creator: McMullan, S
Author/Creator: Berry, C
Author/Creator: Acosta, C
Author/Creator: Lawson, S. N
Description: Muscle spindle afferent (MSA) neurons can show rapid and sustained firing. Immunostaining for the α3 isoform of the Na⁺/K⁺-ATPase (α3) in some large dorsal root ganglion (DRG) neurons and large intrafusal fibres suggested α3 expression in MSAs (Dobretsov et al. 2003), but not whether α3-immunoreactive DRG neuronal somata were exclusively MSAs. We found that neuronal somata with high α3 immunointensity were neurofilament-rich, suggesting they have A-fibres; we therefore focussed on A-fibre neurons to determine the sensory properties of α3-immunoreactive neurons. We examined α3 immunointensity in 78 dye-injected DRG neurons whose conduction velocities and hindlimb sensory receptive fields were determined in vivo. A dense perimeter or ring of staining in a subpopulation of neurons was clearly overlying the soma membrane and not within satellite cells. Neurons with clear α3 rings (n = 23) were all MSAs (types I and II); all MSAs had darkly stained α3 rings, that tended to be darker in MSA1 than MSA2 units. Of 52 non-MSA A-fibre neurons including nociceptive and cutaneous low-threshold mechanoreceptive (LTM) neurons, 50 had no discernable ring, while 2 (Aα/β cutaneous LTMs) had weakly stained rings. Three of three C-nociceptors had no rings. MSAs with strong ring immunostaining also showed the strongest cytoplasmic staining. These findings suggest that α3 ring staining is a selective marker for MSAs. The α3 isoform of the Na⁺/K⁺-ATPase has previously been shown to be activated by higher Na⁺levels and to have greater affinity for ATP than the α1 isoform (in all DRG neurons). The high α3 levels in MSAs may enable the greater dynamic firing range in MSAs.
Description: 13 page(s)
Subject Keyword: 060600 Physiology
Subject Keyword: 111600 Medical Physiology
Resource Type: journal article
Organisation: Macquarie University. Australian School of Advanced Medicine

Identifier: http://hdl.handle.net/1959.14/118044
Identifier: ISSN:0022-3751
Identifier: mq-rm-2010001440
Language: eng
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