Voltage‐dependent currents and modulation of calcium channel expression in zona fasciculata cells from rat adrenal gland.

Barbara, Jean-Gaël; Takeda, Kenneth

doi:10.1113/jphysiol.1995.sp020994

Cited by 45 publications

(50 citation statements)

References 40 publications

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“…These studies have allowed estimates of the affinity of the open channel for Ca 2ϩ . The average K D value from seven studies is 4.9 mM, with considerable variability (range 0.3Ϫ10 mM) (4,22,54,152,160,389,429).…”

Section: J Single-channel Recordingsmentioning

confidence: 97%

“…Calcium currents, and their regulation by secretagogues, have been extensively studied in cells isolated from bovine adrenal zona glomerulosa and fasciculata. Glomerulosa cells express a mixture of T-and L-type channels (82), whereas fasciculata cells predominantly express T-type channels (22,287). Although these cells can be considered nonexcitable due to their lack of Na ϩ channels, they are still capable of generating Ca 2ϩ -dependent action potentials (22).…”

Section: Adrenalmentioning

confidence: 99%

“…Glomerulosa cells express a mixture of T-and L-type channels (82), whereas fasciculata cells predominantly express T-type channels (22,287). Although these cells can be considered nonexcitable due to their lack of Na ϩ channels, they are still capable of generating Ca 2ϩ -dependent action potentials (22). In contrast, adrenal chromaffin cells express HVA Ca 2ϩ and Na ϩ currents but no LVA currents (16).…”

Section: Adrenalmentioning

confidence: 99%

“…It has been noted that the Ca v 3.2 gene contains a region with high homology to the consensus sequence of neural restrictive silencer elements, providing another avenue for future research (342). Transcriptional regulation also appears to be important for hormonal upregulation of T channels (22,447). Studies on gene regulation may also provide insights into the control of T-channel expression during the cell cycle (220).…”

Section: B Future Directionsmentioning

confidence: 99%

“…Cortisol secretion can be inhibited by a variety of blockers including mibefradil, and this block occurs over the same concentration range as their block of the T-type channels (109,141,345). ACTH may also regulate the expression of T-type channels (22).…”

Section: Adrenalmentioning

confidence: 99%

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Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels

Perez‐Reyes

2003

Physiological Reviews

1,518

1,446

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T-type Ca2+ channels were originally called low-voltage-activated (LVA) channels because they can be activated by small depolarizations of the plasma membrane. In many neurons Ca2+ influx through LVA channels triggers low-threshold spikes, which in turn triggers a burst of action potentials mediated by Na+ channels. Burst firing is thought to play an important role in the synchronized activity of the thalamus observed in absence epilepsy, but may also underlie a wider range of thalamocortical dysrhythmias. In addition to a pacemaker role, Ca2+ entry via T-type channels can directly regulate intracellular Ca2+ concentrations, which is an important second messenger for a variety of cellular processes. Molecular cloning revealed the existence of three T-type channel genes. The deduced amino acid sequence shows a similar four-repeat structure to that found in high-voltage-activated (HVA) Ca2+ channels, and Na+ channels, indicating that they are evolutionarily related. Hence, the α1-subunits of T-type channels are now designated Cav3. Although mRNAs for all three Cav3 subtypes are expressed in brain, they vary in terms of their peripheral expression, with Cav3.2 showing the widest expression. The electrophysiological activities of recombinant Cav3 channels are very similar to native T-type currents and can be differentiated from HVA channels by their activation at lower voltages, faster inactivation, slower deactivation, and smaller conductance of Ba2+. The Cav3 subtypes can be differentiated by their kinetics and sensitivity to block by Ni2+. The goal of this review is to provide a comprehensive description of T-type currents, their distribution, regulation, pharmacology, and cloning.

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Section: J Single-channel Recordingsmentioning

confidence: 97%

Section: Adrenalmentioning

confidence: 99%

Section: Adrenalmentioning

confidence: 99%

Section: B Future Directionsmentioning

confidence: 99%

Section: Adrenalmentioning

confidence: 99%

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Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels

Perez‐Reyes

2003

Physiological Reviews

1,518

1,446

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cAMP-dependent protein kinase inhibits the mitogenic action of vascular endothelial growth factor and fibroblast growth factor in capillary endothelial cells by blocking Raf activation

1997

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Proliferation of endothelial cells is regulated by angiogenic and antiangiogenic factors whose actions are mediated by complex interactions of multiple signaling pathways. Both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) stimulate cell proliferation and activate the mitogen-activated protein kinase (MAPK) cascade in bovine brain capillary endothelial (BBE) cells. We have extended these findings to show that both mitogens activate MAPK via stimulation of Raf-3. Activation of Raf/MAPK is inhibited by increasing intracellular cAMP levels pharmacologically or via stimulation of endogenously expressed beta-adrenergic receptors. Both VEGF- and bFGF-induced Raf-1 activity are blocked in the presence of forskolin or 8-bromo-cAMP by 80%. The actions of increased cAMP appear to be mediated by cAMP-dependent protein kinase (PKA), since treatment with H-89, a the specific inhibitor of PKA, reversed the inhibitory effect of elevated cAMP levels on mitogen-induced cell proliferation and Raf/MAPK activation. Moreover, elevations in cAMP/PKA activity inhibit mitogen-induced cell proliferation. These findings demonstrate, in cultured endothelial cells, that the cAMP/PKA signaling pathway is potentially an important physiological inhibitor of mitogen activation of the MAPK cascade and cell proliferation.

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Steroidogenesis—Adrenal Cell Signal Transduction

Gallo‐Payet

Battista

2014

Comprehensive Physiology

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The purpose of this article is to review fundamentals in adrenal gland histophysiology. Key findings regarding the important signaling pathways involved in the regulation of steroidogenesis and adrenal growth are summarized. We illustrate how adrenal gland morphology and function are deeply interconnected in which novel signaling pathways (Wnt, Sonic hedgehog, Notch, β-catenin) or ionic channels are required for their integrity. Emphasis is given to exploring the mechanisms and challenges underlying the regulation of proliferation, growth, and functionality. Also addressed is the fact that while it is now well-accepted that steroidogenesis results from an enzymatic shuttle between mitochondria and endoplasmic reticulum, key questions still remain on the various aspects related to cellular uptake and delivery of free cholesterol. The significant progress achieved over the past decade regarding the precise molecular mechanisms by which the two main regulators of adrenal cortex, adrenocorticotropin hormone (ACTH) and angiotensin II act on their receptors is reviewed, including structure-activity relationships and their potential applications. Particular attention has been given to crucial second messengers and how various kinases, phosphatases, and cytoskeleton-associated proteins interact to ensure homeostasis and/or meet physiological demands. References to animal studies are also made in an attempt to unravel associated clinical conditions. Many of the aspects addressed in this article still represent a challenge for future studies, their outcome aimed at providing evidence that the adrenal gland, through its steroid hormones, occupies a central position in many situations where homeostasis is disrupted, thus highlighting the relevance of exploring and understanding how this key organ is regulated. © 2014 American Physiological Society. Compr Physiol 4:889-964, 2014.

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Voltage‐dependent currents and modulation of calcium channel expression in zona fasciculata cells from rat adrenal gland.

Abstract: 1. Whole-cell voltage-activated currents from single zona fasciculata (ZF) cells from rat adrenal glands were studied. T-and L-type Ca2+ currents and a slowly inactivating A-type K+ current were the three major currents observed.

Cited by 45 publications

References 40 publications

Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels

Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels

cAMP-dependent protein kinase inhibits the mitogenic action of vascular endothelial growth factor and fibroblast growth factor in capillary endothelial cells by blocking Raf activation

Steroidogenesis—Adrenal Cell Signal Transduction

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