ACETYLCHOLINE PRODUCTION IN ANIMALS POISONED BY DIETHYL‐<i>p</i>‐NITROPHENYL PHOSPHATE (PARAOXON)

Barnes, J. M.; Duff, Janet I.

doi:10.1111/j.1476-5381.1954.tb00834.x

Cited by 14 publications

(9 citation statements)

References 9 publications

(6 reference statements)

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“…Decline was more rapid as the frequency of stimulation was increased. Similar results have been reported by others [2,8,24], Reduction in junction transmitter is not significant in most voluntary contractions, since discharge rates are generally between 5 and 25/s [1]. At frequen cies much greater than normal physiological rates, however, reduction in transmitter could become significant.…”

Section: Discussionsupporting

confidence: 76%

Response of Single Alpha Motoneurons to High-Frequency Pulse Trains

Bowman

McNeal²

1986

Stereotact Funct Neurosurg

157

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Studies were conducted on 25 cats to document the discharge rates of alpha motoneurons during stimulation of the sciatic nerve at frequencies from 100 to 10,000 pulses per second (pps). In addition, the feasibility of using high-frequency pulse trains to block the conduction of action potentials was investigated. Two cuff electrodes were placed around the proximal portion of the left sciatic nerve, and recordings of antidromic potentials were taken from single fibers of the L7 ventral root. When stimulating through the more proximal electrode, discharge rates were generally equal to or were subharmonics of the stimulation rate up to 1,000 pps. Firing often decreased in rate during 3-min runs. At 2,000–10,000 pps, fibers responded briefly at rates of several hundred per second but stopped firing within seconds after stimulus initiation. After cessation of response to the high-frequency pulse train, action potentials generated at 50 pps at the more distal electrode did not propagate to the recording electrodes. The ‘electrical block’ so induced was maintained for up to 20 min, and recovery following termination of the pulse train was complete within 1 s.

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Section: Discussionsupporting

confidence: 76%

Response of Single Alpha Motoneurons to High-Frequency Pulse Trains

Bowman

McNeal²

1986

Stereotact Funct Neurosurg

157

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Section: Cholinesterase Inhibitorsmentioning

confidence: 85%

“…After Parathion poisoning, free AcCh in the brain is also increased (DuBois et al, 1949). The appearance of AcCh-like substances in the blood of some mammals after very large doses of cholinesterase inhibitors has also been reported (Douglas & Paton, 1951;Stewart, 1952;Barnes & Duff, 1954).When a cholinesterase inhibitor like F 37 A (methylisopropoxy-dimethylaminoethylthio phosphineoxide) is given to rats in increasing doses, the resulting enzyme inhibition is accompanied by an increase in total brain acetylcholine. At 5 100 200 300 400 DOSE (90 pef kg body wight 1 FIGURE 1.…”

mentioning

confidence: 88%

Mobilization of Acetylcholine by Cholinergic Agents

Holmstedt

1967

Annals of the New York Academy of Sciences

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“…Acetylcholine release per impulse is reduced during stimulation at frequencies above 12/min, whether estimated by bioassay (Barnes & Duff, 1954;Straughan, 1960;Krnjevid & Mitchell, 1961) or by quantum content (Table 1 and Fig. 3).…”

Section: Discussionmentioning

confidence: 99%

“…3). Barnes & Duff (1954) and Straughan (1960) collected ACh from eserinized diaphragm muscles in vitro during 20 min of stimulation at 6-50/sec. Each doubling of frequency of stimulation reduced ACh release per impulse to about three quarters of its previous value.…”

Section: Discussionmentioning

confidence: 99%

Reduction of quantum content during neuromuscular transmission

Brooks¹,

Thies²

1962

The Journal of Physiology

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Failure of muscular contraction during repetitive stimulation of motor nerves has been attributed to transmission block of neuromuscular junctions rather than to inexcitability of nerves or muscles (Waller, 1885; Wedensky, 1884, 1891). Such neuromuscular 'fatigue' is known to occur during prolonged stimulation at frequencies above 40/sec (Rosenblueth, 1950). Rapid stimulation and resultant failure, however, may be unrelated to natural activity because motor nerve fibres discharge during brief reflexes for only fractions of a minute at rates approximating 50/sec. During sustained contractions motor units discharge at rates between 5 and 25/sec (Adrian & Bronk, 1929). At these frequencies some form of presynaptic block may occur: repetitive stiniulation of muscles perfused with Locke's solution at 5-15/sec for several minutes leads to neuromuscular failure and cessation of transmitter release (Dale, Feldberg & Vogt, 1936). This result has been attributed to depletion of acetylcholine (ACh) content of motor nerve terminals (Rosenblueth, Lissak & Lanari, 1939), but failure may have been due to anoxia since muscles perfused with blood maintain their ability to contract (Emmelin & MacIntosh, 1956). Although depletion of ACh content is unlikely, evidence for reduction of ACh release per volley has been produced by del Castillo & Katz (1954b) for frog nerve-muscle preparations stimulated at 2-5/sec. It was suggested that this might forestall exhaustion of ACh content (del Castillo & Katz, 1956).The present experiments were designed to test if ACh release is similarly depressed during stimulation of mammalian nerve-muscle preparations at the moderate rates occurring during natural contractions. It will be shown that stimulation at rates up to 20/sec may cause reduction of ACh release per volley, but that this peripheral event is probably not a major rate limiting factor. A preliminary report of some of the findings has already appeared (Thies, 1960). REDUCED QUANTUM CONTENT 299 METHODS Preparations. Guinea-pigs' serratus muscles were irrigated with physiological saline solution in a 6 ml. Perspex bath; nerves were supported in an adjacent pool of paraffin oil and connected to the muscle bath through a slot filled with petroleum jelly (Brooks, 1956). Physiological saline solutions were warmed to 40°C or left at room temperature (23-25°C) and equilibrated with 95 % 02 and 5 % C02 in 21. reservoirs. Solutions flowed through the bath at 200-300 ml./hr; a thermistor indicated that warmed solutions were at 33380 C while in the bath.Irrigating solutions and drugs. Muscles were irrigated with a modified Krebs's solution whose composition (except where otherwise stated) was (mM): Na+ 143-4, K+ 5-6, Ca2+ 158, Mg2+ 1-0, HCO3-23-8, Cl-130-8 and glucose 5-5 (cf. Creese, Scholes & Taylor, 1958). The solution contained the high bicarbonate concentration, but the phosphate and sulphate of Krebs & Henseleit (1932) were omitted. In many experiments the concentrations of both calcium and magnesium ions were increased four to five ti...

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ACETYLCHOLINE PRODUCTION IN ANIMALS POISONED BY DIETHYL‐p‐NITROPHENYL PHOSPHATE (PARAOXON)

Cited by 14 publications

References 9 publications

Response of Single Alpha Motoneurons to High-Frequency Pulse Trains

Response of Single Alpha Motoneurons to High-Frequency Pulse Trains

Mobilization of Acetylcholine by Cholinergic Agents

Reduction of quantum content during neuromuscular transmission

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