 |
 Previous Article | Next Article 
Journal of Neuroscience, Vol 7, 882-893, Copyright © 1987 by Society for Neuroscience
Blockade of Ca2+ and K+ currents in bag cell neurons of Aplysia californica by dihydropyridine Ca2+ antagonists
JM Nerbonne and AM Gurney
The effects of dihydropyridine calcium antagonists on whole-cell Ca2+ and
K+ currents in the neurosecretory bag cells of the marine mollusc Aplysia
californica have been investigated. Nifedipine and nisoldipine blocked bag
cell Ca2+ currents with effects similar to those seen previously on Ca2+
currents in cardiac muscle: both compounds appeared to interact with Ca2+
channels when they were closed, open, and inactivated. Also, as seen in
cardiac cells, nifedipine apparently binds with higher affinity to Ca2+
channels when they are inactivated than when they are either closed or
open. Nifedipine and nisoldipine also inhibited 2 outward K+ currents in
bag cells: the "delayed rectifier" (IK) and the "A" (IA) currents.
Half-maximal blockade of Ca2+ currents occurred at approximately 1.4 microM
nifedipine, compared to approximately 3-5 microM for half-maximal blockade
of IK and IA. The effects of these compounds on bag cell Ca2+ and K+
currents are interpreted and discussed here in terms of the "modulated
receptor" model of drug action. In contrast, however, no measurable effects
of nifedipine or nisoldipine were seen on Ca2+ (and/or K+) currents in
several vertebrate neuronal cell types. Our results suggest that there are
likely to be structural and/or conformational variations in Ca2+ channels
in different cells, tissues, and/or species and also that, in some cells,
Ca2+ and K+ channels might be structurally similar. These findings also
suggest, therefore, that if dihydropyridine binding is used to identify
Ca2+ channels, care should be taken to ensure that binding correlates
closely with the Ca2+ channels of interest.
This article has been cited by other articles:
|
|
|
|
 
Y. Zhang, N. S. Magoski, and L. K. Kaczmarek
Prolonged Activation of Ca2+-Activated K+ Current Contributes to the Long-Lasting Refractory Period of Aplysia Bag Cell Neurons
J. Neurosci.,
December 1, 2002;
22(23):
10134 - 10141.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. Mitra and M. M. Slaughter
Mechanism of Generation of Spontaneous Miniature Outward Currents (SMOCs) in Retinal Amacrine Cells
J. Gen. Physiol.,
April 2, 2002;
119(4):
355 - 372.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. Mitra and M. M. Slaughter
Calcium-induced Transitions between the Spontaneous Miniature Outward and the Transient Outward Currents in Retinal Amacrine Cells
J. Gen. Physiol.,
April 2, 2002;
119(4):
373 - 388.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Jeziorski, R. Greenberg, and P. Anderson
The molecular biology of invertebrate voltage-gated Ca(2+) channels
J. Exp. Biol.,
January 3, 2000;
203(5):
841 - 856.
[Abstract]
[PDF]
|
|
|
|
|
|
|
J. C. Gomora, J. A. Enyeart, and J. J. Enyeart
Mibefradil Potently Blocks ATP-Activated K+ Channels in Adrenal Cells
Mol. Pharmacol.,
December 1, 1999;
56(6):
1192 - 1197.
[Abstract]
[Full Text]
|
|
|
|
|
|
|
M. C. Jeziorski, R. M. Greenberg, K. S. Clark, and P. A. V. Anderson
Cloning and Functional Expression of a Voltage-gated Calcium Channel alpha 1 Subunit from Jellyfish
J. Biol. Chem.,
August 28, 1998;
273(35):
22792 - 22799.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. Daleau, M. Khalifa, and J. Turgeon
Effects of Cadmium and Nisoldipine on the Delayed Rectifier Potassium Current in Guinea Pig Ventricular Myocytes
J. Pharmacol. Exp. Ther.,
May 1, 1997;
281(2):
826 - 833.
[Abstract]
[Full Text]
|
|
|
|
|
|
|
B. H. White and L. K. Kaczmarek
Identification of a Vesicular Pool of Calcium Channels in the Bag Cell Neurons of Aplysia californica
J. Neurosci.,
March 1, 1997;
17(5):
1582 - 1595.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. J. Hong and G. A. Lnenicka
Characterization of a P-Type Calcium Current in a Crayfish Motoneuron and Its Selective Modulation by Impulse Activity
J Neurophysiol,
January 1, 1997;
77(1):
76 - 85.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. J. Kammermeier and S. W. Jones
High-Voltage-Activated Calcium Currents in Neurons Acutely Isolated From the Ventrobasal Nucleus of the Rat Thalamus
J Neurophysiol,
January 1, 1997;
77(1):
465 - 475.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B Edmonds, M Klein, N Dale, and E. Kandel
Contributions of two types of calcium channels to synaptic transmission and plasticity
Science,
November 23, 1990;
250(4984):
1142 - 1147.
[Abstract]
[PDF]
|
|
|
|
|
|
|
P. Mitra and M. M. Slaughter
Mechanism of Generation of Spontaneous Miniature Outward Currents (SMOCs) in Retinal Amacrine Cells
J. Gen. Physiol.,
April 2, 2002;
119(4):
355 - 372.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. Mitra and M. M. Slaughter
Calcium-induced Transitions between the Spontaneous Miniature Outward and the Transient Outward Currents in Retinal Amacrine Cells
J. Gen. Physiol.,
April 2, 2002;
119(4):
373 - 388.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
