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Electrical activation of mouse dorsal root ganglion (DRG) neurons in cultures for 1-2 days produced a downregulation of voltage sensitive calcium currents, which persisted for > or = 24 h after stimulation was terminated. This regulation varied with different patterns of activation. Both the magnitude and time course of regulation of the low-threshold(More)
Activity-dependent selective reduction of synaptic efficacy is expressed in an in vitro system involving mouse spinal cord and muscle cells. Thrombin or electrical stimulation of the innervating axons induces a decrease in neuromuscular synapse strength, and a specific thrombin inhibitor, hirudin, blocks the electrically evoked down-regulation of synapse(More)
We have studied developmental activity-dependent synapse diminution in both an in vitro tissue culture chamber system and at the intact rodent neuromuscular junction (nmj). In both types of preparations, pre- and postsynaptic alterations in synapse structure and function are produced by manipulations of thrombin (Thr) and protein kinase C (PKC) activity. An(More)
We have used a three compartment tissue culture system that involved two separate populations of cholinergic neurons in the side compartments that converged on a common target population of myotubes in the center compartment. Activation of the axons from one population of neurons produced selective down-regulation of the synaptic inputs from the other(More)
Long-term treatment of rat pituitary tumor cells with epidermal growth factor (EGF) inhibits 45Ca2+ uptake, intracellular calcium levels and subsequent prolactin secretion in response to membrane depolarization. In the present study we have used whole-cell voltage-clamp and single-channel patch-clamp recording to determine directly the effects of EGF (10 nM(More)
Electrical activity during early development affects the development and maintenance of synapses (Spitzer [2006]: Nature 4447:707-712), but the intercellular signals regulating maintenance of synapses are not well identified. At the neuromuscular junction, adenosine 5-triphosphate (ATP) is coreleased with acetylcholine at activated nerve terminals to(More)
Huwentoxin-I (HWTX-I) is a neurotoxic peptide purified from the venom of the Chinese bird spider Selenocosmia huwena. The effects of HWTX-I on neuromuscular transmission of vertebrate skeletal muscle have been investigated by means of twitch tension and electrophysiological techniques. On isolated mouse phrenic nerve-hemidiaphragm preparations, HWTX-I(More)
The Hebb synapse, in which the strength of synapses is affected by activity in presynaptic and postsynaptic nerve cells, is a widely used model for developmental and learning-related neuroplasticity. Presynaptic and postsynaptic firing that is correlated in time is postulated to increase synaptic strength while activity in presynaptic and postsynaptic(More)
PKC plays a critical role in competitive activity-dependent synapse modification at the neuromuscular synapse in vitro and in vivo. This action involves a reduction of the strength of inactive inputs to muscle cells that are activated by other inputs. A decrease of postsynaptic responsiveness and a loss of postsynaptic acetyl choline receptors account for(More)
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