Long-term depression of Aplysia sensorimotor synapses in cell culture: inductive role of a rise in postsynaptic calcium

1996 ◽  
Vol 76 (3) ◽  
pp. 2111-2114 ◽  
Author(s):  
X. Y. Lin ◽  
D. L. Glanzman
Keyword(s):  
Cell Culture ◽  
Synaptic Plasticity ◽  
Sensory Neurons ◽  
Tetraacetic Acid ◽  
Short Term ◽  
Long Term Depression ◽  
Central Synapses ◽  
Postsynaptic Calcium

1. Activation of sensory neurons at 2 Hz for 15 min induces long-term depression (LTD) of isolated Aplysia sensorimotor synapses in cell culture. 2. Prior infusion of the Ca2+ chelator 1,2-bis-(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA) into the postsynaptic motor neuron blocks the induction of LTD, but not short-term synaptic depression. 3. Invertebrate central synapses possess the capacity for LTD. This form of long-term synaptic plasticity may play an important role in learning in Aplysia.

scholarly journals Intracellular Ca2+ Release and Synaptic Plasticity: A Tale of Many Stores

2018 ◽  
Vol 25 (3) ◽  
pp. 208-226 ◽  
Author(s):  
Zahid Padamsey ◽  
William J. Foster ◽  
Nigel J. Emptage
Keyword(s):  
Endoplasmic Reticulum ◽  
Synaptic Plasticity ◽  
Synaptic Function ◽  
Intracellular Organelles ◽  
Short And Long Term ◽  
Central Synapses ◽  
Neural Signaling ◽  
Temporal Extent

Ca2+ is an essential trigger for most forms of synaptic plasticity. Ca2+ signaling occurs not only by Ca2+ entry via plasma membrane channels but also via Ca2+ signals generated by intracellular organelles. These organelles, by dynamically regulating the spatial and temporal extent of Ca2+ elevations within neurons, play a pivotal role in determining the downstream consequences of neural signaling on synaptic function. Here, we review the role of three major intracellular stores: the endoplasmic reticulum, mitochondria, and acidic Ca2+ stores, such as lysosomes, in neuronal Ca2+ signaling and plasticity. We provide a comprehensive account of how Ca2+ release from these stores regulates short- and long-term plasticity at the pre- and postsynaptic terminals of central synapses.

scholarly journals Learning to Discriminate Through Long-Term Changes of Dynamical Synaptic Transmission

2009 ◽  
Vol 21 (12) ◽  
pp. 3408-3428 ◽  
Author(s):  
Christian Leibold ◽  
Michael H. K. Bendels
Keyword(s):  
Synaptic Plasticity ◽  
Learning Rule ◽  
Recurrent Network ◽  
Short Term ◽  
Input Space ◽  
Capacity Limit ◽  
Classical Receptive Field ◽  
Synaptic Changes

Short-term synaptic plasticity is modulated by long-term synaptic changes. There is, however, no general agreement on the computational role of this interaction. Here, we derive a learning rule for the release probability and the maximal synaptic conductance in a circuit model with combined recurrent and feedforward connections that allows learning to discriminate among natural inputs. Short-term synaptic plasticity thereby provides a nonlinear expansion of the input space of a linear classifier, whereas the random recurrent network serves to decorrelate the expanded input space. Computer simulations reveal that the twofold increase in the number of input dimensions through short-term synaptic plasticity improves the performance of a standard perceptron up to 100%. The distributions of release probabilities and maximal synaptic conductances at the capacity limit strongly depend on the balance between excitation and inhibition. The model also suggests a new computational interpretation of spikes evoked by stimuli outside the classical receptive field. These neuronal activities may reflect decorrelation of the expanded stimulus space by intracortical synaptic connections.

scholarly journals Long-Term Effects of Axotomy on Excitability and Growth of Isolated Aplysia Sensory Neurons in Cell Culture: Potential Role of cAMP

1998 ◽  
Vol 79 (3) ◽  
pp. 1371-1383 ◽  
Author(s):  
Supinder S. Bedi ◽  
Ali Salim ◽  
Shanping Chen ◽  
David L. Glanzman
Keyword(s):  
Cell Culture ◽  
Sensory Neurons ◽  
Potential Role ◽  
Morphological Changes ◽  
Axonal Injury ◽  
Long Term Effects ◽  
Cellular Processes ◽  
Neuritic Outgrowth

Bedi, Supinder S., Ali Salim, Shanping Chen, and David L. Glanzman. Long-term effects of axotomy on excitability and growth of isolated Aplysia sensory neurons in cell culture: potential role of cAMP. J. Neurophysiol. 79: 1371–1383, 1998. Crushing nerves, which contain the axons of central sensory neurons, in Aplysia causes the neurons to become hyperexcitable and to sprout new processes. Previous experiments that examined the effects of axonal injury on Aplysia sensory neurons have been performed in the intact animal or in the semi-intact CNS of Aplysia. It therefore has been unclear to what extent the long-term neuronal consequences of injury are due to intrinsic or extrinsic cellular signals. To determine whether injury-induced changes in Aplysia sensory neurons are due to intrinsic or extrinsic signals, we have developed an in vitro model of axonal injury. Isolated central sensory neurons grown for 2 days in cell culture were axotomized. Approximately 24 h after axotomy, sensory neurons exhibited a greater excitability—reflected, in part, as a significant reduction in spike accommodation—and greater neuritic outgrowth than did control (unaxotomized) neurons. Rp diastereoisomer of the cyclic adenosine 3′,5′-monophosphorothiate (Rp-cAMPS), an inhibitor of protein kinase A, blocked both the reduction in accommodation and increased neuritic outgrowth induced by axotomy. Rp-cAMPS also blocked similar, albeit smaller, alterations observed in control sensory neurons during the 24-h period of our experiments. These results indicate that axonal injury elevates cAMP levels within Aplysia sensory neurons, and that this elevation is directly responsible, in part, for the previously described long-term electrophysiological and morphological changes induced in Aplysia sensory neurons by nerve crush. In addition, the results indicate that control sensory neurons in culture are also undergoing injury-related electrophysiological and structural changes, probably due to cellular processes triggered when the neurons are axotomized during cell culturing. Finally, the results provide support for the idea that the cellular processes activated within Aplysia sensory neurons by injury, and those activated during long-term behavioral sensitization, overlap significantly.

Rapid Development of Synaptic Connections and Plasticity Between Sensory Neurons and Motor Neurons of Aplysia in Cell Culture: Implications for Learning and Regulation of Synaptic Strength

1997 ◽  
Vol 77 (5) ◽  
pp. 2316-2327 ◽  
Author(s):  
Rosalind L. Coulson ◽  
Marc Klein
Keyword(s):  
Cell Culture ◽  
Protein Synthesis ◽  
Synaptic Plasticity ◽  
Synaptic Transmission ◽  
Sensory Neurons ◽  
Motor Neurons ◽  
Synapse Formation ◽  
Rapid Development ◽  
Synaptic Connections ◽  
Short Term

Coulson, Rosalind L. and Marc Klein. Rapid development of synaptic connections and plasticity between sensory neurons and motor neurons of Aplysia in cell culture: implications for learning and regulation of synaptic strength. J. Neurophysiol. 77: 2316–2327, 1997. We describe here the time course of functional synapse formation and of the development of short-term synaptic plasticity at Aplysia sensorimotor synapses in cell culture, as well as the effects of blocking protein synthesis or postsynaptic receptors on the development of synaptic transmission and plasticity. We find that synaptic responses can be elicited in 50% of sensory neuron–motor neuron pairs by 1 h after cell contact and that short-term homosynaptic depression and synaptic augmentation and restoration by the endogenous facilitatory transmitter serotonin are present at the earliest stages of synapse formation. Neither block of protein synthesis with anisomycin nor block of two types of postsynaptic glutamate receptor has any effect on the development of synaptic transmission or synaptic plasticity. The rapidity of synapse formation and maturation and their independence of protein synthesis suggest that changes in the number of functional synapses could contribute to short- and intermediate-term forms of synaptic plasticity and learning.

Impact of FII’s and FDI’s on Indian Stock Market

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dr. Kamlesh Kumar Shukla
Keyword(s):  
Stock Market ◽  
Financial Markets ◽  
Global Economy ◽  
Short Term ◽  
Earnings Growth ◽  
The Past ◽  
Bull Market ◽  
Indian Stock Market

FIIs are companies registered outside India. In the past four years there has been more than $41 trillion worth of FII funds invested in India. This has been one of the major reasons on the bull market witnessing unprecedented growth with the BSE Sensex rising 221% in absolute terms in this span. The present downfall of the market too is influenced as these FIIs are taking out some of their invested money. Though there is a lot of value in this market and fundamentally there is a lot of upside in it. For long-term value investors, there’s little because for worry but short term traders are adversely getting affected by the role of FIIs are playing at the present. Investors should not panic and should remain invested in sectors where underlying earnings growth has little to do with financial markets or global economy.

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