Effects of Ca2+ channel antagonist subtypes on mitochondrial Ca2+ transport

doi:10.1016/0922-4106(95)90170-1

European Journal of Pharmacology: Molecular Pharmacology

Volume 289, Issue 1, 15 March 1995, Pages 73-80

https://doi.org/10.1016/0922-4106(95)90170-1 Get rights and content

Abstract

This study was carried out to define the effects of various Ca²⁺ channel modulatory drugs on mitochondrial Ca²⁺ movements. Bovine adrenal medulla mitochondria took up Ca²⁺ at an initial rate of 6.8 nmol mg protein⁻¹ 5 s⁻¹, with a K_m of 15 μM and a B_max of 30 nmol mg protein⁻¹. At 30 μM, neither verapamil, diltiazem, nitrendipine nor Bay K 8644 [methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine-5-carboxylate] affected the initial rate of Ca²⁺ uptake. Ca²⁺-loaded mitochondria retained their Ca²⁺ contents in the presence of ruthenium red for at least 30 min. Cinnarizine and flunarizine, but not verapamil, diltiazem, isradipine, Bay K 8644 or nitrendipine, caused a fast and dramatic Na⁺-independent Ca²⁺ loss. Other Ca²⁺ channel antagonists assayed such as penfluridol, R56865 [N-[1-(4-(4-fluorophenoxy)butyl)]-4-piperidinyl-N-methyl-2-benzothiazolamine], lidoflazine, R87926 [(+)-(S)-4-(2-benzothiazolyl-methylamino)-α-[(3,4-difluorophenoxy) methyl] 1 piperidine] and sabeluzole, also had a mitochondrial Ca²⁺ depleting effect which seemed to be directly related to their octanol/water partition coefficient. The Na⁺-dependent Ca²⁺ efflux from mitochondria was completely inhibited by diltiazem and greatly blocked by nitrendipine. Isradipine caused a moderate blockade and Bay K 8644 and verapamil had no effect. All these data open the possibility of developing novel Ca²⁺ channel antagonists having selective actions on plasmalemmal Ca²⁺ channels, and others with additional and different effects on mitochondrial Ca²⁺ transport. Mitochondria act as a Ca²⁺ sink in pathological ischemic conditions when there is an abnormally high influx of Ca²⁺ into the cell. The prevention of mitochondrial Ca²⁺ overload, in addition to causing plasmalemmal Ca²⁺ channel blockade, might be an important contributing factor to the therapeutic profile of those Ca²⁺ channel antagonists in the treatment of tissue ischemic diseases.

References (16)

W.C. Buss et al.
Effects of calcium channels antagonists on calcium uptake and release by isolated rat cardiac mitochondria
Eur. J. Pharmacol.
(1988)
M. Chiesi et al.
Stereospecific action of diltiazem on the mitochondrial NaCa exchange system and on sarcolemmal Ca-channels
Biochem. Pharmacol.
(1987)
L. Gandía et al.
Relative sensitivities of chromaffin cell calcium channels to organic and inorganic calcium antagonists
Neurosci. Lett.
(1987)
M.G. López et al.
The nicotinic acetylcholine receptor of the bovine chromaffin cell, a new target for dihydropyridines
Eur. J. Pharmacol.
(1993)
C. Montiel et al.
Effects of the novel dihydropyridine Bay-K-8644 on adrenomedullary catecholamine release evoked by calcium reintroduction
Biochem. Biophys. Res. Commun.
(1984)
P.L. Vaghy et al.
Selective inhibition of Na⁺-induced Ca²⁺ release from heart mitochondria by diltiazem and certain other Ca²⁺ antagonists drugs
J. Biol. Chem.
(1982)
G. Zernig
Widening potential for Ca²⁺ antagonists: non-L-type Ca²⁺ channel interaction
Trends Pharmacol. Sci.
(1990)
B.J. Alps et al.
Comparative protective effects of nicardipine, flunarizine, lidoflazine and nimodipine against ischemic injury in the hippocampus of the Mongolian gerbil
Br. J. Pharmacol.
(1988)

There are more references available in the full text version of this article.

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Cytosolic organelles shape calcium signals and exo-endocytotic responses of chromaffin cells
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In contrast, in rat chromaffin cells, mitochondrial uptake rates are 150–300 fold slower but at [Ca2+]c of only 0.2–2 μM, were found [187]. These differences are consistent with dependence of the rate of uptake through the uniporter on the second power of [Ca2+]c [123,124,130,188]. Using mitochondria-targeted aequorin to specifically monitor [Ca2+]M, we found that mitochondria took up about 1100 μmol L cells−1 s−1 upon maximal stimulation of Ca2+ entry into bovine chromaffin cells depolarised with K+ [109,124,130]; this value is comparable with the rate of Ca2+ entry through VDCCs.
The concept of stimulus–secretion coupling was born from experiments performed in chromaffin cells 50 years ago. Stimulation of these cells with acetylcholine enhances calcium (Ca²⁺) entry and this generates a transient elevation of the cytosolic Ca²⁺ concentration ([Ca²⁺]_c) that triggers the exocytotic release of catecholamines. The control of the [Ca²⁺]_c signal is complex and depends on various classes of plasmalemmal calcium channels, cytosolic calcium buffers, the uptake and release of Ca²⁺ from cytoplasmic organelles, such as the endoplasmic reticulum, mitochondria, chromaffin vesicles and the nucleus, and Ca²⁺ extrusion mechanisms, such as the plasma membrane Ca²⁺-stimulated ATPase, and the Na⁺/Ca²⁺ exchanger. Computation of the rates of Ca²⁺ fluxes between the different cell compartments support the proposal that the chromaffin cell has developed functional calcium tetrads formed by calcium channels, cytosolic calcium buffers, the endoplasmic reticulum, and mitochondria nearby the exocytotic plasmalemmal sites. These tetrads shape the Ca²⁺ transients occurring during cell activation to regulate early and late steps of exocytosis, and the ensuing endocytotic responses. The different patterns of catecholamine secretion in response to stress may thus depend on such local [Ca²⁺]_c transients occurring at different cell compartments, and generated by redistribution and release of Ca²⁺ by cytoplasmic organelles. In this manner, the calcium tetrads serve to couple the variable energy demands due to exo–endocytotic activities with energy production and protein synthesis.
Mitochondrial Na+/Ca2+ exchanger, a new target for neuroprotection in rat hippocampal slices
2010, Biochemical and Biophysical Research Communications
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This nimodipine concentration is at least 10-fold higher that required to block L channels [38–40]. At these high concentrations, other 1,4-dihydropyridine (DHP) derivatives such as nitrendipine and isradipine blocks the mNCX [41,42]. It is therefore plausible that at 30 μM, the DHP derivative nimodipine is also inhibiting the mNCX to afford such neuroprotective action.
We tested here the hypothesis that the pharmacological modulation of the mitochondrial Na⁺/Ca²⁺ exchanger (mNCX) could be a new neuroprotective strategy to rescue stressed vulnerable neurons from death. We used rat hippocampal slices incubated with veratridine to cause neuronal death through a mechanism involving Na⁺ and Ca²⁺ overload. CGP37157 (CGP), an inhibitor of the mNCX, rescued veratridine vulnerable neurons from death, showing an EC₅₀ of 5 μM. This neuroprotection was associated to mitigation of veratridine-elicited overproduction of free radicals and to inhibition of the p38 MAPK-linked apoptotic pathway. These results suggest that the mNCX could become a new target to develop compounds with potential therapeutic neuroprotective actions in neurodegenerative diseases.
Prediction of blood-brain partitioning: A model based on ab initio calculated quantum chemical descriptors
2008, Journal of Molecular Graphics and Modelling
A new model for the prediction of log BB, a penetration measure through the blood–brain barrier, based on a molecular set of 82 diverse molecules is developed. The majority of the descriptors are derived from quantum chemical ab initio calculations, augmented with a number of classical descriptors. The quantum chemical information enables one to compute fundamental properties of the molecules. The best set of descriptors was selected by sequential selection and multiple linear regression was used to develop the QSAR model. The predictive capability of the model was tested using internal and external test procedures and the domain of applicability was determined to identify reliable predictions. The selected set of descriptors shows a significant correlation with the experimental log BB. The proposed model could reproduce the data with an error approaching the experimental uncertainty and satisfies the available validation procedures. The obtained results indicate that the use of quantum chemical information in describing molecules improves the behavior of the model.
Chapter 16 Ca2+ dynamics under oxidant stress in the cardiovascular system
2001, Cell and Molecular Response to Stress
Oxidative stress causes cellular injuries that are mediated, at least in part, by an increase in cytosolic Ca²⁺ concentration [Ca²⁺]_i. Disturbances in a variety of mechanisms that normally maintain intracellular Ca²⁺ homeostasis occur during oxidant stress. For example, oxidants, such as hypochlorous acid (HOCL), cause an increase in [Ca²⁺]_i that can be abolished by pretreatment with caffeine. This observation indicated that oxidants modify the activity of internal Ca²⁺ stores. An increase in Ca²⁺ permeability, as a consequence of oxidant stress, also occurred in mitochondria and sarco(endo)plasmic reticular vesicles. Moreover, a depressed Ca²⁺ uptake and an inhibition of sarco(endo)plasmic reticular Ca²⁺ATPase activity occur under oxidant stress. Cytosolic Ca²⁺ overload can occur either by an increase in Ca²⁺ influx from the extra-cellular space to the cytosol or as a result of insufficient Ca²⁺ extrusion from the cytosol. Cytosolic Ca²⁺ concentration is also affected by subcellular Ca ²⁺ store sites, such as the sarco(endo)plasmic reticulum and mitochondria.
Nimodipine and flunarizine have different effects on survival and morphology of PC12 cells during nerve growth factor deprivation
1999, European Journal of Pharmacology
The purpose of this study was to examine the effect of antagonists of different subtypes of Ca²⁺ channels (nimodipine and flunarizine) and two types of Ca²⁺ chelating agents (the cell permeant Ca²⁺ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethylester (BAPTA-AM) and the cell non-permeant Ca²⁺ chelator EGTA) on neurite retraction and cell death of nerve growth factor (NGF)-differentiated PC12 cells after NGF deprivation. We demonstrated that flunarizine and nimodipine, but not BAPTA-AM and EGTA, provided protection against cell death due to NGF deprivation. Using time-lapse videomicroscopy and quantitative image analysis, we found that retraction of neurites was an early and fast phenomenon after removal of NGF. None of the compounds tested (flunarizine, nimodipine, BAPTA-AM, EGTA) could prevent the retraction of neurites.
Mechanisms of neuronal damage in brain hypoxia/ischemia: Focus on the role of mitochondrial calcium accumulation
1998, Pharmacology and Therapeutics
Following a hypoxic-ischemic insult, the collapse of ion gradients results in the inappropriate release of excitatory neurotransmitters. Although excitatory amino acids such as glutamate are the likely extracellular mediators of the ensuing neuronal cell death, the intracellular events occurring downstream of glutamate receptor activation are much less clear. The present review attempts to summarize how Ca ²⁺ overload of neurons following a hypoxic-ischemic insult is neurotoxic. In particular, the interlocked relation between mitochondrial Ca²⁺ accumulation and subsequent neuronal cell death is examined.

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European Journal of Pharmacology: Molecular Pharmacology

Abstract

References (16)

Effects of calcium channels antagonists on calcium uptake and release by isolated rat cardiac mitochondria

Eur. J. Pharmacol.

Stereospecific action of diltiazem on the mitochondrial NaCa exchange system and on sarcolemmal Ca-channels

Biochem. Pharmacol.

Relative sensitivities of chromaffin cell calcium channels to organic and inorganic calcium antagonists

Neurosci. Lett.

The nicotinic acetylcholine receptor of the bovine chromaffin cell, a new target for dihydropyridines

Eur. J. Pharmacol.

Effects of the novel dihydropyridine Bay-K-8644 on adrenomedullary catecholamine release evoked by calcium reintroduction

Biochem. Biophys. Res. Commun.

Selective inhibition of Na⁺-induced Ca²⁺ release from heart mitochondria by diltiazem and certain other Ca²⁺ antagonists drugs

J. Biol. Chem.

Widening potential for Ca²⁺ antagonists: non-L-type Ca²⁺ channel interaction

Trends Pharmacol. Sci.

Comparative protective effects of nicardipine, flunarizine, lidoflazine and nimodipine against ischemic injury in the hippocampus of the Mongolian gerbil

Br. J. Pharmacol.

Cited by (22)

Cytosolic organelles shape calcium signals and exo-endocytotic responses of chromaffin cells

Mitochondrial Na<sup>+</sup>/Ca<sup>2+</sup> exchanger, a new target for neuroprotection in rat hippocampal slices

Prediction of blood-brain partitioning: A model based on ab initio calculated quantum chemical descriptors

Chapter 16 Ca<sup>2+</sup> dynamics under oxidant stress in the cardiovascular system

Nimodipine and flunarizine have different effects on survival and morphology of PC12 cells during nerve growth factor deprivation

Mechanisms of neuronal damage in brain hypoxia/ischemia: Focus on the role of mitochondrial calcium accumulation