A quantitative study of cholinesterase in myoneural junctions from rat and guinea‐pig extraocular muscles

Buckley, G. A.; Heaton, James T.

doi:10.1113/jphysiol.1968.sp008676

Cited by 39 publications

(20 citation statements)

References 12 publications

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“…Regions of higher than average sensitivity for a given fibre were often mapped in detail. A 3 % aqueous solution of Pontamine sky blue 6BX (Gurr) was injected by pressure through a separate micro-electrode into a neighbouring fibre to mark this region and its location was later compared to that of the end-plate as determined by staining for ACh-esterase (Buckley & Heaton, 1968) at the end of the experiment.…”

Section: Methodsmentioning

confidence: 99%

Further studies on the control of ACh sensitivity by muscle activity in the rat.

Lømo¹,

Westgaard²

1975

The Journal of Physiology

224

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1. Denervated rat soleus muscles were stimulated directly through chronically implanted electrodes and the influence of different amounts and patterns of stimuli on the acetylcholine (ACh) sensitivity of the muscle was studied. The number of stimuli was varied by giving similar trains of stimuli (10 Hz for 10 sec) at different intervals (0 to 12 hr). The pattern of stimulation was varied by giving different trains of stimuli (100 Hz for 1 sec, 10 Hz for 10 sec and 1 Hz continuously) as the same average frequency of stimulation (1 Hz). 2. Stimulation usually started 5 days after the denervation when ACh hypersensitivity was fully developed. Most stimulation procedures reduced extrajunctional ACh sensitivity to normal or below normal values within 5‐21 days, and these levels were maintained on prolonged stimulation. 3. The rate at which ACh hypersensitivity disappeared increased with increasing amount and frequency of stimulation. However, as few as 100 stimuli given every 5‐5 hr for 3 weeks caused a tenfold reduction of sensitivity. 4. The stimulation had little or no effect on the ACh sensitivity at the end plate. Along the rest of the fibre the sensitivity was reduced at approximately the same rate except near the tendons where it appeared to fall more slowly in some fibres. 5. The stimulation restored the resting membrane potential of the denervated fibres to normal.

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Section: Methodsmentioning

confidence: 99%

Further studies on the control of ACh sensitivity by muscle activity in the rat.

Lømo¹,

Westgaard²

1975

The Journal of Physiology

224

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show abstract

“…5). Buckley and Nowell (10) and Buckley and Heaton (11), but their method was later found to have yielded low activity (15). In the indirect measurement, the difference of cholinesterase activity between the muscle segments containing motor end plates and the segments without motor end plates is considered to be the cholinesterase activity of motor end plates.…”

Section: Methodsmentioning

confidence: 99%

Cholinesterase activity of motor end plate in human skeletal muscle

Namba¹,

Grob²

1970

J. Clin. Invest.

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“…The diaphragm is composed of a thin sheet of muscle fibres lying parallel to each other, with the phrenic nerve running across the centre at right angles to the fibres. The end-plates of the nerve were located by staining for acetylcholinesterase (Buckley & Heaton, 1968), and all fell very close to the nerve in the centre of each fibre, half-way between the rib and central tendon. To obtain some idea of the distribution of STX binding sites along the length of the muscle fibres, the diaphragm was divided into five regions, parallel to the phrenic nerve and at right angles to the fibres.…”

Section: Denervationmentioning

confidence: 99%

Saxitoxin binding to sodium channels of rat skeletal muscles.

Bay¹,

Strichartz²

1980

The Journal of Physiology

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SUMMARY1. The saturable binding of exchange-labelled tritiated saxitoxin (STX) to the extensor digitorum longus (e.d.l.), diaphragm and soleus muscles of adult rats was studied. By measuring STX uptake to small pieces of muscle, the dissociation constant (KD) and binding capacity could be determined for individual muscles.2. The affinity for STX is very similar in all three muscles, with a KD of 4-3 + 0-3, 5-1 + 0-5 and 4-9 + 0-5 nm (mean + S.E. of mean) at 4 0C for e.d.l., diaphragm and soleus respectively. The maximum binding capacity, which varies between different muscles, is 52-6 + 2-5) 40-3 + 4-9 and 23-8 + 1-1 f-mole. mg wet wt.-' respectively.3. The affinity of e.d.l. for tetrodotoxin (TTX), measured by inhibition of STX binding, is 12-1 + 1-4 nm at 4 0C. Raising the temperature to 37 0C increases the KD for STX to 6-8 + 0-8 nm and the KD for TTX to 47-5 + 4-5 nm.4. STX binding is pH dependent; protons compete with STX for the binding site as if there were a titratable acidic group with a pK of 5.5.5. The binding capacity of the diaphragm is not uniform along the length of the muscle fibres. Binding at the ends of the fibres is only 78 % of that in the central region.6. Denervation of e.d.l. for 7 days causes no change in the affinity for STX. There is a slight reduction in the binding capacity from 54 + 5 to 43 + 3 f-mole. mg wet wt.-'. There is no change in the diameter of the muscle fibres.

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A quantitative study of cholinesterase in myoneural junctions from rat and guinea‐pig extraocular muscles

Cited by 39 publications

References 12 publications

Further studies on the control of ACh sensitivity by muscle activity in the rat.

Further studies on the control of ACh sensitivity by muscle activity in the rat.

Cholinesterase activity of motor end plate in human skeletal muscle

Saxitoxin binding to sodium channels of rat skeletal muscles.

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