Calcium Signaling and Exocytosis in Adrenal Chromaffin Cells

2006 ◽  
Vol 86 (4) ◽  
pp. 1093-1131 ◽  
Author(s):  
Antonio G. García ◽  
Antonio M. García-De-Diego ◽  
Luis Gandía ◽  
Ricardo Borges ◽  
Javier García-Sancho
Keyword(s):  
Endoplasmic Reticulum ◽  
Calcium Channels ◽  
Calcium Channel ◽  
Chromaffin Cells ◽  
Active Sites ◽  
Cultured Cells ◽  
Mammalian Species ◽  
Opiate Receptors ◽  
Catecholamine Release ◽  
High K

At a given cytosolic domain of a chromaffin cell, the rate and amplitude of the Ca2+ concentration ([Ca2+]c) depends on at least four efficient regulatory systems: 1) plasmalemmal calcium channels, 2) endoplasmic reticulum, 3) mitochondria, and 4) chromaffin vesicles. Different mammalian species express different levels of the L, N, P/Q, and R subtypes of high-voltage-activated calcium channels; in bovine and humans, P/Q channels predominate, whereas in felines and murine species, L-type channels predominate. The calcium channels in chromaffin cells are regulated by G proteins coupled to purinergic and opiate receptors, as well as by voltage and the local changes of [Ca2+]c. Chromaffin cells have been particularly useful in studying calcium channel current autoregulation by materials coreleased with catecholamines, such as ATP and opiates. Depending on the preparation (cultured cells, adrenal slices) and the stimulation pattern (action potentials, depolarizing pulses, high K+, acetylcholine), the role of each calcium channel in controlling catecholamine release can change drastically. Targeted aequorin and confocal microscopy shows that Ca2+ entry through calcium channels can refill the endoplasmic reticulum (ER) to nearly millimolar concentrations, and causes the release of Ca2+ (CICR). Depending on its degree of filling, the ER may act as a sink or source of Ca2+ that modulates catecholamine release. Targeted aequorins with different Ca2+ affinities show that mitochondria undergo surprisingly rapid millimolar Ca2+ transients, upon stimulation of chromaffin cells with ACh, high K+, or caffeine. Physiological stimuli generate [Ca2+]c microdomains in which the local subplasmalemmal [Ca2+]c rises abruptly from 0.1 to ∼50 μM, triggering CICR, mitochondrial Ca2+ uptake, and exocytosis at nearby secretory active sites. The fact that protonophores abolish mitochondrial Ca2+ uptake, and increase catecholamine release three- to fivefold, support the earlier observation. This increase is probably due to acceleration of vesicle transport from a reserve pool to a ready-release vesicle pool; this transport might be controlled by Ca2+ redistribution to the cytoskeleton, through CICR, and/or mitochondrial Ca2+ release. We propose that chromaffin cells have developed functional triads that are formed by calcium channels, the ER, and the mitochondria and locally control the [Ca2+]c that regulate the early and late steps of exocytosis.

Role of the Endoplasmic Reticulum and Mitochondria on Quantal Catecholamine Release from Chromaffin Cells of Control and Hypertensive Rats

2009 ◽  
Vol 329 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Regiane Miranda-Ferreira ◽  
Ricardo de Pascual ◽  
Afonso Caricati-Neto ◽  
Luis Gandía ◽  
Aron Jurkiewicz ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Chromaffin Cells ◽  
Catecholamine Release ◽  
Hypertensive Rats

Modulation by endogenously released ATP and opioids of chromaffin cell calcium channels in mouse adrenal slices

2011 ◽  
Vol 300 (3) ◽  
pp. C610-C623 ◽  
Author(s):  
A. Hernández ◽  
P. Segura-Chama ◽  
N. Jiménez ◽  
A. G. García ◽  
J. M. Hernández-Guijo ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Chromaffin Cells ◽  
Opiate Receptors ◽  
Tonic Inhibition ◽  
Inactivation Kinetics ◽  
High Threshold ◽  
Patch Clamp Technique ◽  
Whole Cell ◽  
Voltage Dependent ◽  
Patch Configuration

Modulation of high-threshold voltage-dependent calcium channels by neurotransmitters has been the subject of numerous studies in cultures of neurons and chromaffin cells. However, no studies on such modulation exist in chromaffin cells in their natural environment, the intact adrenal medullary tissue. Here we performed such a study in voltage-clamped chromaffin cells of freshly prepared mouse adrenal slices under the whole cell configuration of the patch-clamp technique. The subcomponents of the whole cell inward Ca2+ current ( ICa) accounted for 49% for L-, 28% for N-, and 36% for P/Q-type channels. T-type Ca2+ channels or residual R-type Ca2+ currents were not seen. However, under the perforated-patch configuration, 20% of ICa accounted for a toxin-resistant R-type Ca2+ current. Exogenously applied ATP and methionine-enkephalin (Met-enk) inhibited ICa by 33%. Stop-flow and Ca2+ replacement by Ba2+, which favored the release of endogenous ATP and opioids, also inhibited ICa, with no changes in activation or inactivation kinetics. This inhibition was partially voltage independent and insensitive to prepulse facilitation. Furthermore, in about half of the cells, suramin and naloxone augmented ICa in the absence of exogenous application of ATP/Met-enk. No additional modulation of ICa was obtained after bath application of exogenous ATP and opioids to these already inhibited cells. Augmentation of ICa was also seen upon intracellular dialysis of guanosine 5′-[β-thio]diphosphate (GDPβS), indicating the existence in the intact slice of a tonic inhibition of ICa in resting conditions. These results suggest that in the intact adrenal tissue a tonic inhibition of ICa exists, mediated by purinergic and opiate receptors.

Plasmalemmal sodium-calcium exchanger shapes the calcium and exocytotic signals of chromaffin cells at physiological temperature

2013 ◽  
Vol 305 (2) ◽  
pp. C160-C172 ◽  
Author(s):  
Juan-Fernando Padín ◽  
José-Carlos Fernández-Morales ◽  
Román Olivares ◽  
Stefan Vestring ◽  
Juan-Alberto Arranz-Tagarro ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Catecholamine Release ◽  
Sodium Calcium Exchanger ◽  
Physiological Temperature ◽  
Slowing Down ◽  
Sodium Calcium ◽  
High K ◽  
Highly Sensitive ◽  
Bovine Chromaffin Cells ◽  
Kinetics Of

The activity of the plasmalemmal Na+/Ca2+ exchanger (NCX) is highly sensitive to temperature. We took advantage of this fact to explore here the effects of the NCX blocker KB-R7943 (KBR) at 22 and 37°C on the kinetics of Ca2+ currents ( ICa), cytosolic Ca2+ ([Ca2+]c) transients, and catecholamine release from bovine chromaffin cells (BCCs) stimulated with high K+, caffeine, or histamine. At 22°C, the effects of KBR on those parameters were meager or nil. However, at 37°C whereby the NCX is moving Ca2+ at a rate fivefold higher than at 22°C, various of the effects of KBR were pronounced, namely: 1) no effects on ICa; 2) reduction of the [Ca2+]c transient amplitude and slowing down of its rate of clearance; 3) blockade of the K+-elicited quantal release of catecholamine; 4) blockade of burst catecholamine release elicited by K+; 5) no effect on catecholamine release elicited by short K+ pulses (1–2 s) and blockade of the responses produced by longer K+ pulses (3–5 s); and 6) potentiation of secretion elicited by histamine or caffeine. Furthermore, the more selective NCX blocker SEA0400 also potentiated the secretory responses to caffeine. The results suggest that at physiological temperature the NCX substantially contributes to shaping the kinetics of [Ca2+]c transients and the exocytotic responses elicited by Ca2+ entry through Ca2+ channels as well as by Ca2+ release from the endoplasmic reticulum.

Blockade of K+ contractures in skeletal muscle by opioid drugs: a nonstereospecific effect

1989 ◽  
Vol 67 (5) ◽  
pp. 435-441
Author(s):  
Tushar G. Kokate ◽  
George B. Frank
Keyword(s):  
Skeletal Muscle ◽  
Calcium Channels ◽  
Opiate Receptors ◽  
Bathing Solution ◽  
Drug Concentrations ◽  
High K ◽  
Opioid Drugs ◽  
Voltage Dependent ◽  
Intracellular Ca ◽  
Sucrose Gap

The effect of several opioid drugs was tested on the K+ contractures in frog's skeletal muscle. These contractures are produced by the entrance of extracellular Ca2+ ions via the voltage-dependent, slow Ca2+ channels located in the T tubules. Morphine and other opioid agonists in concentrations ranging from 10−10 to 10−5 M inhibited K+ contractures. The stereoisomers, dextrorphan and levorphanol, were found to have identical potency in inhibiting high K+ contractures, suggesting that this was a nonstereospecific blockade of voltage-dependent calcium channels by the opioid drugs despite the low effective drug concentrations. In agreement with this conclusion it was found that the inhibition of K+ contractures by the opioids was not antagonized by naloxone. It also was observed using a sucrose gap apparatus that these opioid drugs in concentrations used to block the high K+ contractures did not reduce the K+-induced membrane depolarization. Raising the bathing solution Ca2+ concentration from 1.08 to 5 mM produced a reversal of the opioid-induced block of K+ contractures. Finally it was shown that while opioids completely blocked K+ contractures, they did not produce any effect on caffeine contractures showing that opioids do not deplete intracellular Ca2+ stores or inhibit the release of Ca2+ from intracellular sarcoplasmic reticulum stores. It was concluded that several opioid drugs in very low concentrations block K+ contractures in frog's skeletal muscle by a nonstereospecific block of voltage-dependent slow calcium channels.Key words: opioids, calcium channels, contractures, skeletal muscle, opiate receptors, narcotics.

scholarly journals R56865 inhibits catecholamine release from bovine chromaffin cells by blocking calcium channels

1993 ◽  
Vol 110 (3) ◽  
pp. 1149-1155 ◽  
Author(s):  
Lucía Garcez-Do-Carmo ◽  
Almudena Albillos ◽  
Antonio R. Artalejo ◽  
María-Teresa Fuente ◽  
Manuela G. López ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Chromaffin Cells ◽  
Catecholamine Release ◽  
Bovine Chromaffin Cells

scholarly journals Gabapentin Inhibits Catecholamine Release from Adrenal Chromaffin Cells

2012 ◽  
Vol 116 (5) ◽  
pp. 1013-1024 ◽  
Author(s):  
Robert D. Todd ◽  
Sarah M. McDavid ◽  
Rebecca L. Brindley ◽  
Mark L. Jewell ◽  
Kevin P. M. Currie
Keyword(s):  
Calcium Channel ◽  
Chromaffin Cells ◽  
Single Cells ◽  
Primary Cultures ◽  
Catecholamine Release ◽  
Fluorescent Imaging ◽  
Catecholamine Secretion ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin ◽  
Channel Currents

Background Gabapentin is most commonly prescribed for chronic pain, but acute perioperative effects, including preemptive analgesia and hemodynamic stabilization, have been reported. Adrenal chromaffin cells are a widely used model to investigate neurosecretion, and adrenal catecholamines play important physiologic roles and contribute to the acute stress response. However, the effects of gabapentin on adrenal catecholamine release have never been tested. Methods Primary cultures of bovine adrenal chromaffin cells were treated with gabapentin or vehicle for 18-24 h. The authors quantified catecholamine secretion from dishes of cells using high-performance liquid chromatography and resolved exocytosis of individual secretory vesicles from single cells using carbon fiber amperometry. Voltage-gated calcium channel currents were recorded using patch clamp electrophysiology and intracellular [Ca2+] using fluorescent imaging. Results Gabapentin produced statistically significant reductions in catecholamine secretion evoked by cholinergic agonists (24 ± 3%, n = 12) or KCl (16 ± 4%, n = 8) (mean ± SEM) but did not inhibit Ca2+ entry or calcium channel currents. Amperometry (n = 51 cells) revealed that gabapentin inhibited the number of vesicles released upon stimulation, with no change in quantal size or kinetics of these unitary events. Conclusions The authors show Ca2+ entry was not inhibited by gabapentin but was less effective at triggering vesicle fusion. The work also demonstrates that chromaffin cells are a useful model for additional investigation of the cellular mechanism(s) by which gabapentin controls neurosecretion. In addition, it identifies altered adrenal catecholamine release as a potential contributor to some of the beneficial perioperative effects of gabapentin.

scholarly journals Novel Purine Derivative ITH15004 Facilitates Exocytosis through a Mitochondrial Calcium-Mediated Mechanism

2021 ◽  
Vol 23 (1) ◽  
pp. 440
Author(s):  
Ricardo de Pascual ◽  
Francesco Calzaferri ◽  
Paula C. Gonzalo ◽  
Rubén Serrano-Nieto ◽  
Cristóbal de los Ríos ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Chromaffin Cells ◽  
Ruthenium Red ◽  
Mitochondrial Calcium ◽  
Excitable Cells ◽  
Purine Derivative ◽  
High K

Upon depolarization of chromaffin cells (CCs), a prompt release of catecholamines occurs. This event is triggered by a subplasmalemmal high-Ca2+ microdomain (HCMD) generated by Ca2+ entry through nearby voltage-activated calcium channels. HCMD is efficiently cleared by local mitochondria that avidly take up Ca2+ through their uniporter (MICU), then released back to the cytosol through mitochondrial Na+/Ca2+ exchanger (MNCX). We found that newly synthesized derivative ITH15004 facilitated the release of catecholamines triggered from high K+-depolarized bovine CCs. Such effect seemed to be due to regulation of mitochondrial Ca2+ circulation because: (i) FCCP-potentiated secretory responses decay was prevented by ITH15004; (ii) combination of FCCP and ITH15004 exerted additive secretion potentiation; (iii) such additive potentiation was dissipated by the MICU blocker ruthenium red (RR) or the MNCX blocker CGP37157 (CGP); (iv) combination of FCCP and ITH15004 produced both additive augmentation of cytosolic Ca2+ concentrations ([Ca2+]c) K+-challenged BCCs, and (v) non-inactivated [Ca2+]c transient when exposed to RR or CGP. On pharmacological grounds, data suggest that ITH15004 facilitates exocytosis by acting on mitochondria-controlled Ca2+ handling during K+ depolarization. These observations clearly show that ITH15004 is a novel pharmacological tool to study the role of mitochondria in the regulation of the bioenergetics and exocytosis in excitable cells.

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