Porocytosis: a new approach to synaptic function

Kriebel, Mahlon E.; Keller, Bruce; Silver, Robert B.; Fox, Geoffrey; Pappas, George D.

doi:10.1016/s0165-0173(01)00066-2

Cited by 8 publications

(6 citation statements)

References 79 publications

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“…In our hypothesis, the postsynaptic quantal response results from transmitter pulsed from an array of transient pores rather than from a single presynaptic vesicular exocytotic event (Fig. 1) (Kriebel et al, 2000, 2001). In the mechanism we propose, presynaptic vesicles are anchored to the active zone of the plasma membrane and juxtaposed to calcium ion‐selective channels by proteins such as SNARE (Sudhof, 2000).…”

Section: Porocytosismentioning

confidence: 75%

“…We propose that the arrayed nature of components composing a secretory site provides an ultrastructural basis for the extensive electrophysiological and statistical data that is incompatible with the QVE hypothesis. We view the “secretory organelle” described by Harlow et al, (2001), which we have called the synaptomere (Kriebel et al, 2000, 2001), to be the unit of secretion. The scaffold of the synaptomere positions vesicles in juxtaposition to the neurolemma so that transient pores connect vesicular contents to the synaptic space, permitting a pulse of transmitter.…”

Section: Porocytosismentioning

confidence: 99%

“…Pulsed secretion from each array would ensure a standard postsynaptic quantal response at each of the 200 sites of the neuromuscular junction. An alternative mechanism of secretion compatible with the QVE hypothesis would require that 1 vesicle from each of the 200 sites (each with 50 docked vesicles) is selected for secretion (Kriebel et al, 2001). However, a selection mechanism has not been defined (Schikorski and Stevens, 1997; Kriebel et al, 2004).…”

Section: Synaptomeres and Transmitter Release Sitesmentioning

confidence: 99%

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Porocytosis: A transient pore array secretes the neurotransmitter packet

Kriebel¹,

Keller²,

Silver

et al. 2005

The Anatomical Record Part B

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The porocytosis hypothesis is based on the arrayed nature of synaptic vesicles which forms the anatomical functional unit of secretion. The presynaptic array and the postsynaptic array of receptors form a synaptomere which is the unit of transmission. A transient increase in calcium ions, triggered by an action potential, activates all pores of the array to pulse transmitter. The array insures transmission while permitting a frequency dependent amount of secretion. Therefore the amount of secretion is variable which permits plasticity. Secretion from the array has the property of immediate synaptic plasticity whereas a change in array size would change synaptic strength. The robust nature of the array insures fidelity of transmission, a frequency dependent dynamic signature of transmission giving the property of immediate plasticity; and, a change in array size yields a change in synaptic strength for long term reliability.

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Section: Porocytosismentioning

confidence: 75%

Section: Porocytosismentioning

confidence: 99%

Section: Synaptomeres and Transmitter Release Sitesmentioning

confidence: 99%

See 1 more Smart Citation

Porocytosis: A transient pore array secretes the neurotransmitter packet

Kriebel¹,

Keller²,

Silver

et al. 2005

The Anatomical Record Part B

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“…The analysis is not only relevant to the glutamate-ergic synapses at the crayfish NMJ but also to all chemical synapses across species. The relatively new views of why synaptic responses do not fit precisely in quantal packets due to membrane traffic and glycocalyx within the vesicle as well as the synaptic matrix can also be addressed readily by the use of computational assessments presented (Kriebel et al, 2001;Vautrin and Barker, 2003).…”

Section: Discussionmentioning

confidence: 99%

Self-modeling structure of evoked postsynaptic potentials

Viele¹,

Lancaster²,

Cooper³

2006

Synapse

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With the simplicity of the synaptic structure and physiology at neuromuscular junctions (NMJs) of crayfish and the given transmitter being released in quantal packets, a detailed assessment in the fundamental processes of chemical synaptic transmission is possible. Since the quantal event is the basic element of transmission, we consider an approach to further understand the characteristics of quantal responses. In this study, we introduce a method for combining information across excitatory postsynaptic potentials (EPSPs) that are quantal in nature. The method is called self-modeling regression, known in the statistics literature as SEMOR. This method illustrates that the differing timing and heights of EPSPs can be described with four coefficients measuring affine (shift and scale) transformations of the x and y axes. We demonstrate that this relationship allows us to provide a unified schema for the many functionals currently used in the literature, such as peak amplitude, tau, latency, area under the curve, or decay time. Computer code in R is available on the internet to perform the analysis.

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“…In addition, Vautrin et al (2000) postulated that the postsynaptic responses are indirect as a result of vesicle release but directly an effect of neurotransmitter release from gangliosides on the extracellular presynaptic surface. Others (Kriebel et al, 2001) have recently postulated the existence of temporary pores different than a vesicular fusion pore to release transmitter.…”

Section: Discussionmentioning

confidence: 99%

Estimating the number of release sites and probability of firing within the nerve terminal by statistical analysis of synaptic charge

Viele¹,

Stromberg²,

Cooper³

2002

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Investigating the function of individual synapses is essential to understanding the mechanisms that influence the efficacy of chemical synaptic transmission. The known simplicity of the synaptic structure at the crayfish neuromuscular junction (NMJ) and its quantal nature of release allows an assessment of discrete synapses within the motor nerve terminals. Our goal in this article is to investigate the effect of the stimulation frequency on the number of active release sites (n) and the probability of release (p) at those active sites. Because methods based on direct counts often provide unstable joint estimates of (n) and (p), we base our analysis on mixture modeling. In particular, the mixture modeling approach is used to estimate (n) and (p) for stimulation frequencies of 1 Hz, 2 Hz, and 3 Hz. Our results indicate that as the stimulation frequency increases, new sites are recruited (thus increasing n) and the probability of release (p) increases.

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Porocytosis: a new approach to synaptic function

Cited by 8 publications

References 79 publications

Porocytosis: A transient pore array secretes the neurotransmitter packet

Porocytosis: A transient pore array secretes the neurotransmitter packet

Self-modeling structure of evoked postsynaptic potentials

Estimating the number of release sites and probability of firing within the nerve terminal by statistical analysis of synaptic charge

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