The effect of calcium ions on the binomial statistic parameters which control acetylcholine release at synapses in striated muscle.

Bennett, Max R.; Florin, Todd; Hall, Robert M.

doi:10.1113/jphysiol.1975.sp010939

Cited by 54 publications

(56 citation statements)

References 31 publications

(44 reference statements)

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“…As shown by Meiri & Rahamimoff, flsr = 0 4 gave a good fit to experimental observations at the neuromuscular junction, consistent with Sr2+ acting as a partial agonist of X, while very low ft would apply for a competitive inhibitor, such as Mg2+ (Jenkinson, 1957 Dodge & Rahamimoff, 1967;Meiri & Rahamimoff, 1971;Bennett, Florin & Hall, 1975). A value of n = 0-8 during steady-state release at 10 Hz (unpublished personal observations) was derived from the slope of the relationship between log m and log [Ca] for three other ganglionic synapses.…”

Section: Effects On Membrane Propertiesmentioning

confidence: 69%

The effects of strontium and barium ions at synapses in sympathetic ganglia.

McLachlan¹

1977

The Journal of Physiology

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Section: Effects On Membrane Propertiesmentioning

confidence: 69%

The effects of strontium and barium ions at synapses in sympathetic ganglia.

McLachlan¹

1977

The Journal of Physiology

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“…Unsuspected nonstationarities or nonuniformities associated with changes in mean quantal content can create illusory or exaggerated changes in some of the release statistics, but can also mask true changes. In this connection, it is important to note that the lability of fi reported in several studies (6,11,12,14,15,(17)(18)(19) does not distinguish between the two theoretical possibilities: (i) that release occurs from a fixed number of specialized release sites (8,9,(25)(26)(27)(28)(29)(30)(31) or (fi) that it occurs from a more variable "available store" of quanta (5,11,14,17,18,25,26).…”

Section: Discussionmentioning

confidence: 99%

“…1 and a variance ar2 = np(1 -p). The sample mean m and variance s2 are used in the standard moment formulas to obtain estimates p and fi of the population parameters p and n: p -(s2/m) W1 -(02/U) [3] n = m/p [4] The applicability of the binomial model to neurotransmitter release has been explored at both invertebrate (5-10) and vertebrate synapses (8,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). When m, the mean quantal content, has not been deliberately reduced, the observed distribution of X is in general better fitted by a binomial than a Poisson law.…”

mentioning

confidence: 99%

Evoked neurotransmitter release: statistical effects of nonuniformity and nonstationarity.

Brown¹,

Perkel²,

Feldman³

1976

Proc. Natl. Acad. Sci. U.S.A.

111

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Recent studies of the mechanism of quantal neurotransmitter release have assumed that the number of quanta released at each stimulation is binomially distributed and have sought to estimate the binomial parameters n and p. Mathematical analysis and computer simulations show that temporal variation in the number of eligible or filled release sites and either spatial or temporal variation in the probability of release at a site can drastically bias such estimates, while the experimental histograms remain statistically indistinguishable from those predicted by the binomial law. Interpretation of the estimates n and p in terms of ultrastructural or physiological characteristics of the nerve terminal is liable to significant error if departures from the binomial assumptions are not suitably assessed.

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“…The larger the size of a nerve terminal the more quanta it releases in response to a nerve impulse (Kuno, Turkanis & Weakly 1971) and this is probably due to larger terminals possessing larger n values (Bennett & Florin, 1974;Bennett, Florin & Hall, 1975). In the present work this dependence of n on terminal size has been put on a quantitative basis by determining both the average size of nerve terminals at a particular 288 REGRESSION OF SYNAPSES developmental stage and the average value of n at the synapses and comparing these estimates at different developmental stages.…”

Section: Discussionmentioning

confidence: 99%

The formation and regression of synapses during the re‐innervation of axolotl striated muscles.

Bennett¹,

Raftos²

1977

The Journal of Physiology

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102

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SUMMARY1. A study has been made of the formation and regression of synapses formed by spinal nerves 16 and 17 in axolotl hind-limb flexor muscles following the severing of nerve 16, using histological, ultrastructural and electrophysiological techniques.2. Axolotl hind-limb flexor myofibres possessed 'en plaque' end-plates from either spinal nerve 16 or 17 or both at intervals of about 1000 um along their length; the myofibre's length constant was about 700 ,m allowing electrophysiological observations of at least two of these synapses during a single impalement; transmitter release at these synapses could be described by binomial statistics and in a given set of ionic conditions the binomial statistic parameter n was directly proportional to the size of the nerve terminals whilst the binomial statistic parameter p was invariant to changes in nerve terminal size.3. The distribution of synapses formed by spinal nerves 16 and 17 in different sectors of the axolotl hind-limb flexor muscles was determined from a study of evoked end-plate potentials; the middle and proximal sectors of the flexor muscles contained myofibres which received an innervation from nerve 16 only, whereas the sectors surrounding these contained myofibres innervated either by nerve 16 or nerve 17 or by both nerves.4. Six days following the severing of spinal nerve 16, evoked transmitter release from the synapses formed by this nerve had failed; transmission was subsequently recorded at a few synapses formed by nerve 17 in the middle and proximal sectors of the flexor muscles which are not normally innervated by this nerve and these synapses had a low n; during the succeeding four weeks the value of n at the synapses increased to a size about 70 % that of the terminals normally formed by nerve 16 at these sites.II-2 M. R. BENNETT AND JULIA RAFTOS 5. Four weeks after severing nerve 16, myofibres which possessed synapses formed by nerve 17 also possessed synapses from re-innervating nerve 16 and these were sometimes formed at the same synaptic sites as those occupied by nerve 17.6. In the subsequent sixteen weeks, the n value of synapses formed by nerve 17 declined whilst the n values of synapses formed by reinnervating nerve 16 on the same myofibres matured to their control size.7. It is suggested that on severing nerve 16 collateral sprouting of nearby intact nerve 17 occurs and these collateral sprouts innervate the denervated synaptic sites, although the sprouts are not as well matched to the denervated synaptic sites as are the original nerve terminals; thus if nerve 16 returns it preferentially forms synapses at its original synaptic sites, and the collateral synapses formed by nerve 17 regress.

show abstract

The effect of calcium ions on the binomial statistic parameters which control acetylcholine release at synapses in striated muscle.

Cited by 54 publications

References 31 publications

The effects of strontium and barium ions at synapses in sympathetic ganglia.

The effects of strontium and barium ions at synapses in sympathetic ganglia.

Evoked neurotransmitter release: statistical effects of nonuniformity and nonstationarity.

The formation and regression of synapses during the re‐innervation of axolotl striated muscles.

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