Two types of A-channels in Lymnaea neurons

1995 ◽  
Vol 146 (3) ◽  
Author(s):  
S.I. Alekseev ◽  
M.C. Ziskin
Keyword(s):  
Lymnaea Neurons

Nonlinear activity of identified Lymnaea neurons

2000 ◽  
Vol 51 (2-4) ◽  
pp. 237-242
Author(s):  
M. Barbi ◽  
S. Chillemi ◽  
A. Di Garbo ◽  
G. Molnár ◽  
A. Szűcs
Keyword(s):  
Lymnaea Neurons

Nerve growth factor (NGF) acutely enhances high-voltage-activated calcium currents in molluscan neurons

1995 ◽  
Vol 74 (6) ◽  
pp. 2778-2781 ◽  
Author(s):  
W. C. Wildering ◽  
J. C. Lodder ◽  
K. S. Kits ◽  
A. G. Bulloch
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
High Voltage ◽  
Signal Transduction Pathway ◽  
Calcium Currents ◽  
Molluscan Neurons ◽  
Experimental Conditions ◽  
Nerve Growth ◽  
Physiological Properties ◽  
Lymnaea Neurons

1. Nerve growth factor (NGF) is a member of a family of molecules (the neurotrophins) that can regulate the survival and/or outgrowth of many vertebrate cells. NGF also induces outgrowth from Lymnaea neurons under experimental conditions. Recent studies have shown that the neurotrophins can also acutely modulate some physiological properties of adult neurons. Here we examined the actions of NGF on high-voltage-activated (HVA) Ca2+ currents in Lymnaea motoneurons. 2. NGF induced a dose-dependent and reversible increase in HVA Ca2+ currents within 2 min. 3. The threshold dose of the NGF-induced enhancement of HVA Ca2+ currents ranged between 1 and 1,000 pg/ml. In the most sensitive cells, the response saturated at doses higher than 1 ng/ml. 4. The results indicate that neurotrophins acutely modulate voltage-gated Ca2+ currents in molluscan neurons through a high affinity signal transduction pathway. The data support the existence of neurotrophins in invertebrates. Moreover, this property of NGF may explain the neuromodulatory actions of neurotrophins observed in various preparations.

scholarly journals Voltage- and Calcium-Dependent Inactivation of Calcium Channels in Lymnaea Neurons

1999 ◽  
Vol 114 (4) ◽  
pp. 535-550 ◽  
Author(s):  
Shalini Gera ◽  
Lou Byerly
Keyword(s):  
Cytochalasin B ◽  
Lymnaea Stagnalis ◽  
Slow Component ◽  
Freshwater Snail ◽  
High Concentration ◽  
Calcium Dependent ◽  
Channel Inactivation ◽  
Dependent Inactivation ◽  
Lymnaea Neurons ◽  
Ca2 Channels

Ca2+ channel inactivation in the neurons of the freshwater snail, Lymnaea stagnalis, was studied using patch-clamp techniques. In the presence of a high concentration of intracellular Ca2+ buffer (5 mM EGTA), the inactivation of these Ca2+ channels is entirely voltage dependent; it is not influenced by the identity of the permeant divalent ions or the amount of extracellular Ca2+ influx, or reduced by higher levels of intracellular Ca2+ buffering. Inactivation measured under these conditions, despite being independent of Ca2+ influx, has a bell-shaped voltage dependence, which has often been considered a hallmark of Ca2+-dependent inactivation. Ca2+-dependent inactivation does occur in Lymnaea neurons, when the concentration of the intracellular Ca2+ buffer is lowered to 0.1 mM EGTA. However, the magnitude of Ca2+-dependent inactivation does not increase linearly with Ca2+ influx, but saturates for relatively small amounts of Ca2+ influx. Recovery from inactivation at negative potentials is biexponential and has the same time constants in the presence of different intracellular concentrations of EGTA. However, the amplitude of the slow component is selectively enhanced by a decrease in intracellular EGTA, thus slowing the overall rate of recovery. The ability of 5 mM EGTA to completely suppress Ca2+-dependent inactivation suggests that the Ca2+ binding site is at some distance from the channel protein itself. No evidence was found of a role for serine/threonine phosphorylation in Ca2+ channel inactivation. Cytochalasin B, a microfilament disrupter, was found to greatly enhance the amount of Ca2+ channel inactivation, but the involvement of actin filaments in this effect of cytochalasin B on Ca2+ channel inactivation could not be verified using other pharmacological compounds. Thus, the mechanism of Ca2+-dependent inactivation in these neurons remains unknown, but appears to differ from those proposed for mammalian L-type Ca2+ channels.

Diversity of nicotinic receptors mediating Cl− current in Lymnaea neurons distinguished with specific agonists and antagonist

2005 ◽  
Vol 373 (3) ◽  
pp. 232-236 ◽  
Author(s):  
C.A. Vulfius ◽  
O.B. Tumina ◽  
I.E. Kasheverov ◽  
Yu.N. Utkin ◽  
V.I. Tsetlin
Keyword(s):  
Nicotinic Receptors ◽  
Lymnaea Neurons

scholarly journals Development of Ca 2+ hotspots between Lymnaea neurons during synaptogenesis

2002 ◽  
Vol 539 (1) ◽  
pp. 53-65 ◽  
Author(s):  
Zhong‐Ping Feng ◽  
Nikita Grigoriev ◽  
David Munno ◽  
Ken Lukowiak ◽  
Brian A. MacVicar ◽  
...  
Keyword(s):  
Lymnaea Neurons

Delayed activation of single mechanosensitive channels in Lymnaea neurons

1994 ◽  
Vol 267 (2) ◽  
pp. C598-C606 ◽  
Author(s):  
D. L. Small ◽  
C. E. Morris
Keyword(s):  
Dynamic Behavior ◽  
Abrupt Onset ◽  
Fundamental Difference ◽  
K Channel ◽  
Mechanosensitive Channels ◽  
Stretch Activation ◽  
Open Probability ◽  
K Channels ◽  
Voltage Dependent ◽  
Lymnaea Neurons

Some stretch-activated (SA) channels challenged with suction jumps exhibit adaptation, a dynamic behavior that can be overlooked because of its mechanical fragility. In previous studies of neuronal SA K channels, we detected no adaptation, but the protocols used were not designed to detect dynamics. Here, we reproduce the adaptation seen by others in Xenopus SA cationic (Cat) channels but show that, with the same protocol, no adaptation occurs with SA K channels. Instead, SA K channels exhibit a different dynamic behavior, delayed activation. Lymnaea SA K channels subjected to pressure jumps responded after a 1- to 4-s delay with a gradual, rather than abrupt, onset of activation. The delay was pressure dependent and was longer for patches from older cultured neurons. Delayed responses were fragile like SA Cat channel adaptation; they disappeared with repeated stimuli. Cytochalasin D decreased the delay and increased the stretch activation of SA K channels. Unlike SA Cat channel adaptation, which occurs only at hyperpolarized potentials, SA K channel delay was not voltage dependent. We note that once SA Cat and SA K channels are "stripped" of their fragile (cytoskeleton-dependent?) dynamics, however, their gating behaviors show little fundamental difference; both are stretch activatable and have a higher open probability at depolarized potentials.

Sign in / Sign up

Export Citation Format

Share Document