Actomyosin-Like Protein in Brain

Berl, S.

doi:10.1007/978-1-4757-4395-1_5

Cited by 45 publications

(60 citation statements)

References 82 publications

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“…These observations, allied with the mor phological ones relating to the distribution of vesicles and intraterminal profiles and to the shape of the terminals, can be accounted for by postulating an interruption to vesicular mechanisms at the cleft and to membrane re uptake mechanisms along the plasma mem brane away from the cleft in the anaestheti zed terminals [24,26,27,35], This, in turn, may be a consequence of the action of pento barbitone in inhibiting the actomyosin sys tem [5,36]. It appears as if actin-like fila ments are in contact with the dense projec tions of the pre-synaptic vesicular grid [24,29], and hence may be responsible for the distribution of vesicles in the vicinity of the pre-synaptic membrane.…”

Section: Discussionmentioning

confidence: 99%

Synaptic Parameters in Developing Rat Cerebral Cortex: Comparison of Anaesthetized and Unanaesthetized States

Devon

Jones

1981

Dev Neurosci

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The ultrastructure of synapses from the molecular layer of parietal cortex was examined in male rats aged between 7 and 75 days. Two groups were compared, one group consisting of rats anaesthetized with 50 mg/kg pentobarbitone and the other consisting of those killed by stunning across the back of the neck. Various synaptic parameters were analyzed. In the anaesthetized material, the sectioned area of the pre-synaptic terminals decreases between 7 and 75 days, as does the number of terminals containing intraterminal profiles other than synaptic vesicles. Mean synaptic vesicle number per terminal increases, while the remaining parameters fluctuate over the developmental period. Comparing these data with those from the unanaesthetized material, the only parameters showing similar trends are the pre-synaptic terminal area, the mean vesicle number per terminal, and the length of the post-synaptic thickening. The remaining parameters are comparable up to 15 or 21 days post-natally, after which they diverge. The percentage of terminals containing intraterminal profiles, the terminal perimeter and the mean vesicle density in the unanaesthetized terminals all show increased values. The form factor indicates these terminals are more ellipsoidal by 75 days, while the mean synaptic curvature is more positive by 75 days. It is concluded that the synaptic organization of the early terminals differs from that of the older ones, and this may be related to different mechanisms of transmitter storage and release.

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Section: Discussionmentioning

confidence: 99%

Synaptic Parameters in Developing Rat Cerebral Cortex: Comparison of Anaesthetized and Unanaesthetized States

Devon

Jones

1981

Dev Neurosci

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“…Treatment with 1-MA forms transient surface spikes which arise due to polymerization of actin (24,25), or decreases of stiffness of oocytes (20) which is also thought to be the result of the changes of cytoskeleton. Cytoskeletal elements (actomyosin-like proteins) are responsible for bringing the granular membrane and plasma membrane together in brain (2). These correlations between oocyte maturation and exocytosis will give a clue for understanding the process of cortical maturation.…”

Section: Discussionmentioning

confidence: 99%

Three Phases of Cortical Maturation during Meiosis Reinitiation in Starfish Oocytes

Chiba

Hoshi

1989

Dev Growth Differ

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Oocytes of the starfish, Asterina pectinifera, respond differently to calcium ionophore A231 87 depending upon their stage of maturation. Oocytes not-treated with I-methyladenine (I-MA) formed only a partial fertilization envelope (FE) in response to A23187. Those treated with 1-MA formed no FE if the ionophore was introduced to them before germinal vesicle breakdown (GVBD), in contrast with which they did fully elevate the FE if it was introduced after GVBD. Similar stage-dependent results were obtained if the intracellular concentration of calcium was increased by microinjection of calcium-EGTA buffers. In good accordance with the FE formation, a stage-dependent protease release from oocytes by the ionophore was observed.It is concluded from these results that, in starfish oocytes, their ability to undergo the exocytosis of cortical granules in response to an increase in intracellular calcium greatly changes along the way of maturation.

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“…In synaptic terminals neurotransmitter-containing vesicles are maintained in large clusters in apposition to the site of membrane f usion and must be mobilized in synchrony with vesicle f usion to sustain synaptic transmission during repetitive stimulation. It has long been hypothesized that the elevation of intracellular C a 2ϩ , which promotes membrane f usion, also might serve as a trigger for vesicle mobilization and transport (Berl et al, 1973). Recent studies at different types of central synapses (Stevens and Wesseling, 1998;Wang and Kaczmarek, 1998) indicate that the resupply of vesicles after stimulation is accelerated by elevations of intracellular Ca 2ϩ .…”

mentioning

confidence: 99%

Inhibitors of Myosin Light Chain Kinase Block Synaptic Vesicle Pool Mobilization during Action Potential Firing

1999

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During repetitive action potential firing the maintenance of synaptic transmission relies on a continued supply of synaptic vesicles for fusion with the presynaptic plasma membrane. The mechanism of transport by which vesicles are delivered to the site of fusion from a reserve pool is unknown, as are the biochemical pathways linking intracellular Ca 2ϩ elevation with vesicle mobilization. Here, using the fluorescent tracer FM1-43 in hippocampal synaptic terminals, I show that inhibitors of myosin light chain kinase can block mobilization of the reserve pool and not the immediately releasable pool.

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Actomyosin-Like Protein in Brain

Cited by 45 publications

References 82 publications

Synaptic Parameters in Developing Rat Cerebral Cortex: Comparison of Anaesthetized and Unanaesthetized States

Synaptic Parameters in Developing Rat Cerebral Cortex: Comparison of Anaesthetized and Unanaesthetized States

Three Phases of Cortical Maturation during Meiosis Reinitiation in Starfish Oocytes

Inhibitors of Myosin Light Chain Kinase Block Synaptic Vesicle Pool Mobilization during Action Potential Firing

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