Cholinergic Receptor Molecules and Cholinesterase Molecules at Mouse Skeletal Muscle Junctions

Barnard, Eric A.; J, Wieckowski; Chiu, Tsung‐Hong

doi:10.1038/234207a0

Cited by 206 publications

(81 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reason for the small number of molecules of (+ )-tubocurarine (4 x 106) bound to an endplate at complete neuromuscular blockade (Waser, 1967) in comparison with the number of a-BuTX-receptive sites in our experiment and in others is not known. It may be due to a wash-out of (+)-tubocurarine, as proposed by Barnard et al (1971), or to an allosteric nature of the action, as proposed by Waser (1967) and Miledi & Potter (1971).…”

Section: Discussionmentioning

confidence: 99%

“…Preparations of a-BuTX, either iodinated with '3II (Lee & Tseng, 1966;Lee et al, 1967;Miledi & Potter, 1971; or 125I (Berg et al, 1972), or acetylated with [3H] acetic anhydride (Barnard et al, 1971) have been used for this purpose. However, these labelled toxins were used without purification, and the question arises whether they were contaminated with the unchanged toxin, or with inactive derivatives, and if so, whether the labelled preparation still possesses the same biological activity as the original toxin.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

N,O‐di andN,N,O‐tri [³H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors

Chang

Chen

Chuang

1973

British J Pharmacology

View full text Add to dashboard Cite

Summary α‐Bungarotoxin isolated from the venom of Bungarus multicinctus was acetylated with [3H] acetic anhydride and N‐[3H] acetyl imidazole. Tri‐N‐acetyl and hexa‐N‐acetyl derivatives were obtained from the former, and N,O‐di, N,N,O‐tri and N,N,N,O‐tetraacetyl derivatives from the latter reaction, respectively. There were parallel decreases in both neuromuscular blocking action in the phrenic nerve—diaphragm preparation of rats and depression of acetylcholine response of the rectus abdominis muscle of frogs with increased acetylation. Also, a parallel but greater decrease of toxicity in mice was found. N,O‐Di and N,N,O‐triacetyl toxins were localized mostly in the motor endplate region of the rat diaphragm, whereas a slight nonspecific binding along the whole muscle fibre in addition to the peak in the endplate region was observed with N,N,N,O‐tetraacetyl and tri‐N‐acetyl toxins. In contrast, there was a marked nonspecific binding with hexa‐N‐acetyl toxin and no peak was observed at the endplate zone. The specific binding was saturable and irreversible. The number of toxin‐receptive sites in one endplate was 1·9–2·2 × 107 for all of the labelled toxins irrespective of their potency. (+)‐Tubocurarine protected effectively against the binding as well as the irreversible neuromuscular blocking effect of the toxins. Denervation of the rat diaphragm caused an increase of toxin‐receptive sites beginning from the endplate zone at 1–2 days and then along the whole muscle fibre, reaching the maximum at about 18 days. The total receptive sites increased by about 30‐fold. The significance of the findings is discussed and it is concluded that N,O‐di and N,N,O‐tri‐[3H] acetyl α‐bungarotoxins are specific and irreversible labelling agents for the cholinergic receptors of skeletal muscle.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

N,O‐di andN,N,O‐tri [³H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors

Chang

Chen

Chuang

1973

British J Pharmacology

View full text Add to dashboard Cite

show abstract

“…Grain density at different distances from the line drawn over the crests of thejunctional foldswas determined as described by Fertuck and Salpeter (16) . The grain density was expressed in HDs (or half distance of exposed grains) from this line a-BuTX-binding Studies These experiments were conducted to insure that a-BuTX-binding sites were 2 HD or half distance is the distance in which half of all exposed grains from a linear radioactive source fall. In this case, with Ilford L4, 1 251 and D19 developer, the HD value was determined to be -80 nm .…”

Section: Analysis Of Autoradiogramsmentioning

confidence: 99%

“…Various studies (for review see reference 12) have shown that the number of AChR at endplates in mice (2), rats (14,31), frogs (31), and humans (13) is quite similar. Electron microscope autoradiographic studies have demonstrated a relatively constant density (16,28,30,(33)(34)(35) and distribution (16,(33)(34)(35) of AChR at endplates of vertebrate skeletal muscle .…”

mentioning

confidence: 99%

Density and distribution of α-bungarotoxin-binding sites in postsynaptic structures of regenerated rat skeletal muscle

Bader¹

1981

The Journal of Cell Biology

View full text Add to dashboard Cite

Acetylcholine receptors (AChR) are organized in a discrete and predictable fashion in the postsynaptic regions of vertebrate skeletal muscle . When muscle is damaged, nerves and myofibers including muscular elements of the endplate degenerate, but the connective tissue elements survive. Muscle fibers regenerate within the basal lamina of the original myofiber . Postsynaptic differentiation in regenerated mammalian skeletal muscle can occur in different ways : (a) at the site of the original endplate in the presence or absence of the nerve, or (b) at ectopic regions of the regenerated myofiber in the presence of the nerve when the original endplate is not present. The present study used '251-a-bungarotoxin (1251 -a-BuTX) and EM autoradiography to examine the density and distribution of AChR in postsynaptic structures regenerated at the site of the original endplate in the absence of the nerve and at ectopic sites of the myofiber in the presence of the nerve when the original endplate was removed . In regenerated myofibers, the density of a-BuTX-binding sites fell within the range of densities observed in uninjured muscle whether postsynaptic differentiation occurred at the site of the original endplate in the absence of the nerve or at an originally ectopic position of the regenerated myofiber . In addition, the distribution of a-BuTX-binding sites within the regenerated postsynaptic regions closely resembled the distribution of a-BuTX-binding sites in uninjured muscle . Morphometric analysis was performed on postsynaptic structures formed at the site of the original endplate in the absence of the nerve or at an ectopic position of the regenerated myofiber by interaction of the nerve and muscle . Although variation in the depth of the primary cleft occurred, there was little difference between the overall structure of regenerated postsynaptic structures and that of endplates of uninjured muscles.The density of acetylcholine receptors (AChR) at innervated motor endplates of skeletal muscle has been determined by both physiological (23, 25) and morphological (16,28,30,(33)(34)(35) means. Various studies (for review see reference 12) have shown that the number of AChR at endplates in mice (2), rats (14, 31), frogs (31), and humans (13) is quite similar. Electron microscope autoradiographic studies have demonstrated a relatively constant density (16,28,30,(33)(34)(35) and distribution (16,(33)(34)(35) of AChR at endplates of vertebrate skeletal muscle .When skeletal muscle grafts are made, the neuromuscular junctions are disrupted by the degeneration of the myofibers and the nerves that supply them (7,10,29,37, and footnote 1).' Carlson, B. M., P. Hnik, S. Tucek, R. Vejsada, and D. Bader. 338It has been established that synapses are formed in the regenerated muscle of amphibians (29, 37) and mammals (1,3,10). Marshall et al . (29) have shown that, in regenerating frog muscle, neuromuscular connections are almost always at the site of the original endplate . Burden et al . (7) have demonstrated that postsyna...

show abstract

“…Muscle is a much poorer source of ACh.R, and even after its proliferation following denervation it is far below the level in the electric organ of Torpedo. For muscles, quantitation and localisation of ACh.R, by exploitation of its essentially irreversible binding of labelled cu-bungarotoxin (BuTX), was initially described [3], and solubilisation of this ACh.R in detergents and some fractionation has been reported [4-71. Subsequently [S] , we reported upon a preparation, partly purified by affinity chromatography, of the form of ACh.R which is responsible for the extrajunctional ACh sensitivity of denervated mammalian muscle. We have further applied affinity chromatography in a more bio-specific form (in the sense in which this technique has been critically reviewed by Barry and O'Carra [9] ), and describe here the complete purification of this muscle ACh.R.…”

Section: Introductionmentioning

confidence: 99%

Complete purification of the acetylcholine receptor protein from mammalian muscle

Dolly¹,

Barnard²

1975

FEBS Letters

View full text Add to dashboard Cite

Cholinergic Receptor Molecules and Cholinesterase Molecules at Mouse Skeletal Muscle Junctions

Cited by 206 publications

References 18 publications

N,O‐di andN,N,O‐tri [³H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors

N,O‐di andN,N,O‐tri [³H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors

Density and distribution of α-bungarotoxin-binding sites in postsynaptic structures of regenerated rat skeletal muscle

Complete purification of the acetylcholine receptor protein from mammalian muscle

Contact Info

Product

Resources

About

Cholinergic Receptor Molecules and Cholinesterase Molecules at Mouse Skeletal Muscle Junctions

Cited by 206 publications

References 18 publications

N,O‐di andN,N,O‐tri [3H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors

N,O‐di andN,N,O‐tri [3H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors

Density and distribution of α-bungarotoxin-binding sites in postsynaptic structures of regenerated rat skeletal muscle

Complete purification of the acetylcholine receptor protein from mammalian muscle

Contact Info

Product

Resources

About

N,O‐di andN,N,O‐tri [³H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors

N,O‐di andN,N,O‐tri [³H] acetyl α‐bungarotoxins as specific labelling agents of cholinergic receptors