Single channel properties of newly synthesized acetylcholine receptors following denervation of mammalian skeletal muscle

L. P. Henderson, J. D. Lechleiter, Paul Brehm

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

We have examined the single channel properties of newly synthesized acetylcholine (ACh) receptors in denervated adult mouse muscle. Patch-clamp recordigns were made on freshly isolated fibers from flexor digitorum brevis (fdb) muscles that had been denervated in vivo for periods up to 3 wk. Muscles were treated with α-bungarotoxin (α-BTX), immediately before denervation, in order to block pre-existing receptors. Denervated fibers exhibited two types of ACh receptor channels, which differed in terms of single channel conductance (45 and 70pS) and mean channel open time (~7 and 2.5ms, respectively). In contrast to innervated muscle, where only 3% of the total openings were contributed by the low-conductance channel type, >80% of the openings in the nonsynaptic membrane of denervated muscle were of this type. Importantly, a similar increase in the proportion of low-conductance channels was observed for recordings from synaptic membrane after denervation. These data argue against the proposal that, in denervated muscle, the low-conductance channels undergo continued conversion to the high-conductance type focally at the site of former synaptic contact. Rather, our findings provide additional support for the idea that the functional properties of ACh receptors are governed uniformly by the state of innervation of the fiber and not by proximity to the site of synaptic contact.

Original languageEnglish (US)
Pages (from-to)999-1014
Number of pages16
JournalJournal of General Physiology
Volume89
Issue number6
StatePublished - 1987
Externally publishedYes

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Cholinergic Receptors
Denervation
Skeletal Muscle
Muscles
Bungarotoxins
Synaptic Membranes
Membranes

ASJC Scopus subject areas

  • Physiology

Cite this

Single channel properties of newly synthesized acetylcholine receptors following denervation of mammalian skeletal muscle. / Henderson, L. P.; Lechleiter, J. D.; Brehm, Paul.

In: Journal of General Physiology, Vol. 89, No. 6, 1987, p. 999-1014.

Research output: Contribution to journalArticle

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