scholarly journals Minireview: Aldosterone Biosynthesis: Electrically Gated for Our Protection

Endocrinology ◽  
2012 ◽  
Vol 153 (8) ◽  
pp. 3579-3586 ◽  
Author(s):  
Nick A. Guagliardo ◽  
Junlan Yao ◽  
Changlong Hu ◽  
Paula Q. Barrett
Keyword(s):  
Time Course ◽  
Low Voltage ◽  
Salt Water ◽  
Zona Glomerulosa ◽  
Membrane Voltage ◽  
Disease States ◽  
Voltage Dependent ◽  
Aldosterone Production ◽  
Ca2 Channels

Aldosterone produced by adrenal zona glomerulosa (ZG) cells plays an important role in maintaining salt/water balance and, hence, blood pressure homeostasis. However, when dysregulated, aldosterone advances renal and cardiovascular disease states. Multiple steps in the steroidogenic pathway require Ca2+, and the sustained production of aldosterone depends on maintained Ca2+ entry into the ZG cell. Nevertheless, the recorded membrane potential of isolated ZG cells is extremely hyperpolarized, allowing the opening of only a small fraction of low-voltage-activated Ca2+ channels of the Cav3.x family, the major Ca2+ conductance on the ZG cell membrane. As a consequence, to activate sufficient Ca2+ channels to sustain the production of aldosterone, aldosterone secretagogs would be required to affect large decreases in membrane voltage, a requirement that is inconsistent with the exquisite sensitivity of aldosterone production in vivo to small changes (0.1 mm) in extracellular K+. In this review, we evaluate the contribution of membrane voltage and voltage-dependent Ca2+ channels to the control of aldosterone production and consider data highlighting the electrical excitability of the ZG cell. This intrinsic capacity of ZG cells to behave as electrical oscillators provides a platform from which to generate a recurring Ca2+ signal that is compatible with the lengthy time course of steroidogenesis and provides an alternative model for the physiological regulation of aldosterone production that permits both amplitude and temporal modulation of the Ca2+ signal.

scholarly journals Quantitative assessment of CYP11B1 and CYP11B2 expression in aldosterone-producing adenomas

2002 ◽  
pp. 795-802 ◽  
Author(s):  
F Fallo ◽  
V Pezzi ◽  
L Barzon ◽  
P Mulatero ◽  
F Veglio ◽  
...  
Keyword(s):  
Real Time ◽  
Secretory Activity ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Pathophysiological Role ◽  
Aldosterone Production

BACKGROUND: The presence and pathophysiological role of CYP11B1 (11beta-hydroxylase) gene in the zona glomerulosa of human adrenal cortex is still controversial. METHODS: In order to specifically quantify CYP11B1, CYP11B2 (aldosterone synthase) and CYP17(17alpha-hydroxylase) mRNA levels, we developed a real-time RT-PCR assay and examined the expression in a series of adrenal tIssues, including six normal adrenals from patients adrenalectomized for renal cancer and twelve aldosterone-producing adenomas (APA) from patients with primary aldosteronism. RESULTS: CYP11B1 mRNA levels were clearly detected in normal adrenals, which comprised both zona glomerulosa and fasciculata/reticularis cells, but were also measured at a lower range (P<0.05) in APA. The levels of CYP11B2 mRNA were lower (P<0.005) in normal adrenals than in APA. CYP17 mRNAlevels were similar in normal adrenals and in APA. In patients with APA, CYP11B2 and CYP11B1 mRNA levels were not correlated either with basal aldosterone or with the change from basal aldosterone in response to posture or to dexamethasone. No correlation between CYP11B1 mRNA or CYP11B2 mRNA and the percentage of zona fasciculata-like cells was observed in APA. CONCLUSIONS: Real-time RT-PCR can be reliably used to quantify CYP11B1 and CYP11B2 mRNA levels in adrenal tIssues. Expression of CYP11B1 in hyperfunctioning zona glomerulosa suggests an additional formation of corticosterone via 11beta-hydroxylase, providing further substrate for aldosterone biosynthesis. CYP11B1 and CYP11B2 mRNA levels in APA are not related to the in vivo secretory activity of glomerulosa cells, where post-transcriptional factors might ultimately regulate aldosterone production.

scholarly journals Voltage-gated transient currents in bovine adrenal fasciculata cells. I. T-type Ca2+ current.

1993 ◽  
Vol 102 (2) ◽  
pp. 217-237 ◽  
Author(s):  
B Mlinar ◽  
B A Biagi ◽  
J J Enyeart
Keyword(s):  
Time Constant ◽  
Low Voltage ◽  
Zona Fasciculata ◽  
Patch Clamp Technique ◽  
Time Constants ◽  
Voltage Gated ◽  
Wide Range ◽  
Boltzmann Function ◽  
Voltage Dependent ◽  
Ca2 Channels

The whole cell version of the patch clamp technique was used to identify and characterize voltage-gated Ca2+ channels in enzymatically dissociated bovine adrenal zona fasciculata (AZF) cells. The great majority of cells (84 of 86) expressed only low voltage-activated, rapidly inactivating Ca2+ current with properties of T-type Ca2+ current described in other cells. Voltage-dependent activation of this current was fit by a Boltzmann function raised to an integer power of 4 with a midpoint at -17 mV. Independent estimates of the single channel gating charge obtained from the activation curve and using the "limiting logarithmic potential sensitivity" were 8.1 and 6.8 elementary charges, respectively. Inactivation was a steep function of voltage with a v1/2 of -49.9 mV and a slope factor K of 3.73 mV. The expression of a single Ca2+ channel subtype by AZF cells allowed the voltage-dependent gating and kinetic properties of T current to be studied over a wide range of potentials. Analysis of the gating kinetics of this Ca2+ current indicate that T channel activation, inactivation, deactivation (closing), and reactivation (recovery from inactivation) each include voltage-independent transitions that become rate limiting at extreme voltages. Ca2+ current activated with voltage-dependent sigmoidal kinetics that were described by an m4 model. The activation time constant varied exponentially at test potentials between -30 and +10 mV, approaching a voltage-independent minimum of 1.6 ms. The inactivation time constant (tau i) also decreased exponentially to a minimum of 18.3 ms at potentials positive to 0 mV. T channel closing (deactivation) was faster at more negative voltages; the deactivation time constant (tau d) decreased from 8.14 +/- 0.7 to 0.48 +/- 0.1 ms at potentials between -40 and -150 mV. T channels inactivated by depolarization returned to the closed state along pathways that included two voltage-dependent time constants. tau rec-s ranged from 8.11 to 4.80 s when the recovery potential was varied from -50 to -90 mV, while tau rec-f decreased from 1.01 to 0.372 s. At potentials negative to -70 mV, both time constants approached minimum values. The low voltage-activated Ca2+ current in AZF cells was blocked by the T channel selective antagonist Ni2+ with an IC50 of 20 microM. At similar concentrations, Ni2+ also blocked cortisol secretion stimulated by adrenocorticotropic hormone. Our results indicate that bovine AZF cells are distinctive among secretory cells in expressing primarily or exclusively T-type Ca2+ channels.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of CO2/pH on the aldosterone response to hypoxia in bovine adrenal cells in vitro

1993 ◽  
Vol 265 (4) ◽  
pp. R820-R825
Author(s):  
H. Raff ◽  
B. Jankowski
Keyword(s):  
Respiratory Acidosis ◽  
Inhibitory Effect ◽  
Zona Glomerulosa ◽  
Ang Ii ◽  
Adrenal Cells ◽  
Aldosterone Production ◽  
Per Se ◽  
Air Control

Acidosis increases and hypoxia decreases aldosterone production from the adrenal zona glomulerosa in vivo, in situ, and in vitro. These effects appear to be located at different steps in the steroidogenic process. Because respiratory acidosis and hypoxemia are common sequelae of chronic lung disease, the present experiments evaluated the interaction of hypoxia and CO2 (with uncompensated or compensated extracellular pH) on aldosteronogenesis in vitro. Bovine adrenal zona glomerulosa cells were stimulated with angiotensin II (ANG II) or adenosine 3',5'-cyclic monophosphate under room air control (21% O2-0% CO2), CO2 per se (21% O2-10% CO2), hypoxia per se (10% O2-0% CO2), and the combination of CO2 and hypoxia (10% O2-10% CO2). Furthermore, under CO2, pH was either allowed to decrease from 7.2 to 6.8 (uncompensated) or its decrease was minimized (> 7.05) with NaOH (compensated). CO2 without pH compensation led to a significant increase in ANG II-stimulated aldosterone release; when the decrease in pH was minimized, CO2 inhibited ANG II-stimulated aldosterone release. Hypoxia inhibited aldosterone release; the inhibitory effect of hypoxia predominated when combined with CO2. In the presence of cyanoketone, pregnenolone production from endogenous precursors (early pathway) was unaffected. However, the conversion of corticosterone to aldosterone (late pathway) was inhibited by low O2 but unaffected by CO2. It is concluded that the inhibitory effect of low O2 on the late pathway predominates over the effects of uncompensated or compensated simulated respiratory acidosis on aldosteronogenesis.

scholarly journals The Orphan Nuclear Receptors NURR1 and NGFIB Regulate Adrenal Aldosterone Production

2004 ◽  
Vol 18 (2) ◽  
pp. 279-290 ◽  
Author(s):  
Mary H. Bassett ◽  
Takashi Suzuki ◽  
Hironobu Sasano ◽  
Perrin C. White ◽  
William E. Rainey
Keyword(s):  
Kinase Inhibitor ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Related Factor ◽  
Mrna Levels ◽  
Ang Ii ◽  
Orphan Nuclear Receptors ◽  
Protein Levels ◽  
Aldosterone Production

Abstract Aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex is regulated by transcription of CYP11B2 (encoding aldosterone synthase). The effects of nerve growth factor-induced clone B (NGFIB) (NR4A1), Nur-related factor 1 (NURR1) (NR4A2), and steroidogenic factor-1 (SF-1) (NR5A1) on transcription of human CYP11B2 (hCYP11B2) and hCYP11B1 (11β-hydroxylase) were compared in human H295R adrenocortical cells. hCYP11B2 expression was increased by NGFIB and NURR1. Although hCYP11B1 was activated by SF-1, cotransfection with SF-1 inhibited activation of hCYP11B2 by NGFIB and NURR1. NGFIB and NURR1 transcript and protein levels were strongly induced by angiotensin (Ang) II, the major regulator of hCYP11B2 expression in vivo. Sequential deletion and mutagenesis of the hCYP11B2 promoter identified two functional NGFIB response elements (NBREs), one located at −766/−759 (NBRE-1) and the previously studied Ad5 element at −129/−114. EMSAs suggested that both elements bound NGFIB and NURR1. In human adrenals, NURR1 immunoreactivity was preferentially localized in the zona glomerulosa and to a lesser degree in the zona fasciculata, whereas NGFIB was detected in both zones. The calmodulin kinase inhibitor KN93 partially blocked K+-stimulated transcription of NGFIB and NURR1. KN93 partially inhibited the effect of Ang II on NURR1 mRNA levels but did not modify the effect on expression of NGFIB. Mutation of the NBRE-1, Ad5, and Ad1/cAMP response element (CRE) cis-elements reduced both basal and Ang II-induced levels of hCYP11B2, demonstrating that all three elements are important for maximal transcriptional activity. Our results suggest that NGFIB and NURR1 are key regulators of hCYP11B2 expression and may partially mediate the regulation of hCYP11B2 by Ang II.

scholarly journals Is there a role for T-type Ca2+ channels in regulation of vasomotor tone in mesenteric arterioles?This article is part of a Special Issue on Information Transfer in the Microcirculation.

2009 ◽  
Vol 87 (1) ◽  
pp. 8-20 ◽  
Author(s):  
Lars Jørn Jensen ◽  
Niels-Henrik Holstein-Rathlou
Keyword(s):  
Information Transfer ◽  
Electromechanical Coupling ◽  
Low Voltage ◽  
Vasomotor Tone ◽  
Direct Demonstration ◽  
Voltage Dependent ◽  
Small Conductance ◽  
Ca2 Channels ◽  
Peripheral Blood Pressure

The largest peripheral blood pressure drop occurs in terminal arterioles (<40 µm lumen diameter). L-type voltage-dependent Ca2+ channels (VDCCs) are considered the primary pathway for Ca2+ influx during physiologic activation of vascular smooth muscle cells (VSMC). Recent evidence suggests that T-type VDCCs are expressed in renal afferent and efferent arterioles, mesenteric arterioles, and skeletal muscle arterioles. T-type channels are small-conductance, low voltage-activated, fast-inactivating channels. Thus, their role in supplying Ca2+ for contraction of VSMC has been disputed. However, T-type channels display non-inactivating window currents, which may play a role in sustained Ca2+ entry. Here, we review the possible role of T-type channels in vasomotor tone regulation in rat mesenteric terminal arterioles. The CaV3.1 channel was immunolocalized in VSMC, whereas the CaV3.2 channel was predominantly expressed in endothelial cells. Voltage-dependent Ca2+ entry was inhibited by the new specific T-type blockers R(–)-efonidipine and NNC 55-0396. The effect of NNC 55-0396 persisted in depolarized arterioles, suggesting an unusually high activation threshold of mesenteric T-type channels. T-type channels were not necessary for conduction of vasoconstriction, but appear to be important for local electromechanical coupling in VSMC. The first direct demonstration of endothelial T-type channels warrants new investigations of their role in vascular biology.

Kinetic and pharmacological properties of low voltage-activated Ca2+ current in rat clonal (GH3) pituitary cells

1992 ◽  
Vol 68 (1) ◽  
pp. 213-232 ◽  
Author(s):  
J. Herrington ◽  
C. J. Lingle
Keyword(s):  
Time Course ◽  
Low Voltage ◽  
Gh3 Cells ◽  
Pituitary Cells ◽  
Anesthetic Agents ◽  
Channel Opening ◽  
Cell Recording ◽  
Voltage Dependent ◽  
Dependent Processes ◽  
Site Binding

1. Low voltage-activated (LVA) Ca2+ current in clonal (GH3) pituitary cells was studied with the use of the whole-cell recording technique. The use of internal fluoride to facilitate the rundown of high voltage-activated (HVA) Ca2+ current allowed the study of LVA current in virtual isolation. 2. In 10 mM [Ca2+]o, detectable LVA current begins to appear at about -50 mV, with half-maximal activation occurring at -33 mV. The time course of activation was best described by a Hodgkin-Huxley expression with n = 3, suggesting that at least three closed states must be traversed before channel opening. 3. Deactivation was found to vary exponentially with membrane potential between -60 and -160 mV, indicating that channel closing is rate-limited by a single, voltage-dependent transition. 4. Onset and removal of inactivation between -40 and -130 mV were best described by the sum of two exponentials. Between -80 and -130 mV, both components of removal of inactivation showed little voltage dependence, with time constants of approximately 200-300 ms and 1-2 s. At membrane potentials above -40 mV, a single component of inactivation onset was detected. This component was voltage independent between -20 and +20 mV (tau = 22 ms). Thus inactivation of LVA current is best described by multiple, voltage-in-dependent processes. 5. Significant inactivation of LVA current occurred at -65 mV without detectable macroscopic current. This suggests that inactivation is not strictly coupled to channel opening. 6. Peak LVA current increased with increasing [Ca2+]o, with saturation approximately 50 mM. The Ca(2+)-dependence of peak LVA current was reasonably well described by a single-site binding isotherm with half-maximal LVA current at approximately 7 mM. 7. LVA current in GH3 cells was largely resistant to blockade by Ni2+. The relative potency of inorganic cations in blocking GH3 LVA current was (concentrations which produced 50% block): La3+ (2.4 microM) greater than Cd2+ (188 microM) greater than Ni2+ (777 microM). 8. Several organic agents, including putative LVA blockers, HVA current blockers and various anesthetic agents, were tested for their ability to block LVA current. The concentrations that produced 50% block are as follows: nifedipine (approximately 50 microM), D600 (51 microM), diltiazem (131 microM), octanol (244 microM), pentobarbital (985 microM), methoxyflurane (1.41 mM), and amiloride (1.55 mM). Phenytoin and ethosuximide produced 36 and 10% block at 100 microM and 2.5 mM, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Voltage-gated calcium channels in GtoPdb v.2021.2

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
William A. Catterall ◽  
Edward Perez-Reyes ◽  
Terrance P. Snutch ◽  
Jörg Striessnig
Keyword(s):  
High Voltage ◽  
Low Voltage ◽  
Transmembrane Domains ◽  
Voltage Gated ◽  
Voltage Dependent ◽  
Alternatively Spliced ◽  
Membrane Spanning ◽  
Voltage Gated Ion Channels ◽  
Ca2 Channels ◽  
Α1 Subunit

Calcium (Ca2+) channels are voltage-gated ion channels present in the membrane of most excitable cells. The nomenclature for Ca2+channels was proposed by [127] and approved by the NC-IUPHAR Subcommittee on Ca2+ channels [70]. Most Ca2+ channels form hetero-oligomeric complexes. The α1 subunit is pore-forming and provides the binding site(s) for practically all agonists and antagonists. The 10 cloned α1-subunits can be grouped into three families: (1) the high-voltage activated dihydropyridine-sensitive (L-type, CaV1.x) channels; (2) the high- to moderate-voltage activated dihydropyridine-insensitive (CaV2.x) channels and (3) the low-voltage-activated (T-type, CaV3.x) channels. Each α1 subunit has four homologous repeats (I-IV), each repeat having six transmembrane domains and a pore-forming region between transmembrane domains S5 and S6. Voltage-dependent gating is driven by the membrane spanning S4 segment, which contains highly conserved positive charges that respond to changes in membrane potential. All of the α1-subunit genes give rise to alternatively spliced products. At least for high-voltage activated channels, it is likely that native channels comprise co-assemblies of α1, β and α2-δ subunits. The γ subunits have not been proven to associate with channels other than the α1s skeletal muscle Cav1.1 channel. The α2-δ1 and α2-δ2 subunits bind gabapentin and pregabalin.

Low-voltage activated calcium currents increase in basal forebrain neurons from aged rats

1995 ◽  
Vol 74 (2) ◽  
pp. 876-887 ◽  
Author(s):  
D. Murchison ◽  
W. H. Griffith
Keyword(s):  
Time Course ◽  
Low Voltage ◽  
Age Groups ◽  
Medial Septum ◽  
Calcium Currents ◽  
Fischer 344 ◽  
Diagonal Band ◽  
Whole Cell Patch Clamp ◽  
Age Related ◽  
Voltage Dependent

1. Whole cell patch-clamp recordings were made of low-voltage-activated (LVA) calcium (Ca2+) currents using 2 mM barium (Ba2+) as charge carrier. Acutely dissociated neurons from medial septum (MS) and the nucleus of the diagonal band (nDB) were examined in young adult (1–3 mo) and aged (24–26 mo) Fischer 344 rats. 2. Most neurons in both age groups displayed LVA currents: 84% of young cells (110/131) and 87% in aged cells (62/71). Using cell capacitance as an indication of cell size, aged cells were significantly smaller (P < 0.05; 15.4 +/- 0.6 pF; mean +/- SE) than young cells (18.0 +/- 0.5 pF), although a single distribution of cell sizes was present in both populations. 3. The LVA currents were enhanced in cells from aged animals. When LVA currents were studied without activation of high voltage activated currents, the current density (pA/pF) was significantly (P < 0.05) increased at negative potentials in aged neurons (young: 4.92 +/- 0.35 pA/pF; Aged: 5.92 +/- 0.45 pA/pF, at a prepulse potential of -110 mV). No change in voltage-dependent activation or inactivation was seen. The time course of recovery from inactivation also was unchanged. 4. Kinetic parameters of LVA currents were compared in both age groups. No age-related difference in time-dependent activation or inactivation was observed. A single distribution of decay time constants of LVA currents was present in both age groups. 5. These results show that MS/nDB cells maintain robust LVA currents and have increased current densities in very old rats. An increased LVA current in the aged neurons suggests that their ability to fire rhythmically or in bursts is retained or enhanced and that the resulting increase in intracellular Ca2+ may contribute to an altered Ca2+ homeostasis.

scholarly journals GRK2-Mediated Crosstalk Between β-Adrenergic and Angiotensin II Receptors Enhances Adrenocortical Aldosterone Production In Vitro and In Vivo

2020 ◽  
Vol 21 (2) ◽  
pp. 574
Author(s):  
Celina M. Pollard ◽  
Jennifer Ghandour ◽  
Natalie Cora ◽  
Arianna Perez ◽  
Barbara M. Parker ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
G Protein ◽  
Adrenal Cortex ◽  
Zona Glomerulosa ◽  
Type I ◽  
Signaling Crosstalk ◽  
Aldosterone Production ◽  
Steroidogenic Acute Regulatory

Aldosterone is produced by adrenocortical zona glomerulosa (AZG) cells in response to angiotensin II (AngII) acting through its type I receptors (AT1Rs). AT1R is a G protein-coupled receptor (GPCR) that induces aldosterone via both G proteins and the adapter protein βarrestin1, which binds the receptor following its phosphorylation by GPCR-kinases (GRKs) to initiate G protein-independent signaling. β-adrenergic receptors (ARs) also induce aldosterone production in AZG cells. Herein, we investigated whether GRK2 or GRK5, the two major adrenal GRKs, is involved in the catecholaminergic regulation of AngII-dependent aldosterone production. In human AZG (H295R) cells in vitro, the βAR agonist isoproterenol significantly augmented both AngII-dependent aldosterone secretion and synthesis, as measured by the steroidogenic acute regulatory (StAR) protein and CYP11B2 (aldosterone synthase) mRNA inductions. Importantly, GRK2, but not GRK5, was indispensable for the βAR-mediated enhancement of aldosterone in response to AngII. Specifically, GRK2 inhibition with Cmpd101 abolished isoproterenol’s effects on AngII-induced aldosterone synthesis/secretion, whereas the GRK5 knockout via CRISPR/Cas9 had no effect. It is worth noting that these findings were confirmed in vivo, since rats overexpressing GRK2, but not GRK5, in their adrenals had elevated circulating aldosterone levels compared to the control animals. However, treatment with the β-blocker propranolol prevented hyperaldosteronism in the adrenal GRK2-overexpressing rats. In conclusion, GRK2 mediates a βAR-AT1R signaling crosstalk in the adrenal cortex leading to elevated aldosterone production. This suggests that adrenal GRK2 may be a molecular link connecting the sympathetic nervous and renin-angiotensin systems at the level of the adrenal cortex and that its inhibition might be therapeutically advantageous in hyperaldosteronism-related conditions.

Mechanisms of histamine-induced relaxation in bovine small adrenal cortical arteries

2005 ◽  
Vol 289 (6) ◽  
pp. E1058-E1063 ◽  
Author(s):  
David X. Zhang ◽  
Kathryn M. Gauthier ◽  
William B. Campbell
Keyword(s):  
Blood Flow ◽  
Mast Cell ◽  
Receptor Antagonist ◽  
Zona Glomerulosa ◽  
Receptor Antagonists ◽  
Vascular Events ◽  
Nitric Oxide Synthase Inhibitor ◽  
Aldosterone Production ◽  
Synthase Inhibitor

Adrenal steroidogenesis is closely correlated with increases in adrenal blood flow. Many reports have studied the regulation of adrenal blood flow in vivo and in perfused glands, but until recently few studies have been conducted on isolated adrenal arteries. The present study examined vasomotor responses of isolated bovine small adrenal cortical arteries to histamine, an endogenous vasoactive compound, and its mechanism of action. In U-46619-precontracted arteries, histamine (10−9-5 × 10−6 M) elicited concentration-dependent relaxations. The relaxations were blocked by the H1 receptor antagonists diphenhydramine (10 μM) or mepyramine (1 μM) (maximal relaxations of 18 ± 6 and 22 ± 6%, respectively, vs. 55 ± 5% of control) but only partially inhibited by the H2 receptor antagonist cimetidine (10 μM) and the H3 receptor antagonist thioperamide (1 μM). Histamine-induced relaxations were also blocked by the nitric oxide synthase inhibitor N-nitro-l-arginine (l-NA, 30 μM; maximal relaxation of 13 ± 7%) and eliminated by endothelial removal or l-NA combined with the cyclooxgenase inhibitor indomethacin (10 μM). In the presence of adrenal zona glomerulosa (ZG) cells, histamine did not induce further relaxations compared with histamine alone. Histamine (10−7-10−5 M) concentration-dependently increased aldosterone production by adrenal ZG cells. Compound 48/80 (10 μg/ml), a mast cell degranulator, induced significant relaxations (93 ± 0.6%), which were blocked by l-NA plus indomethacin or endothelium removal, partially inhibited by the combination of the H1, H2, and H3 receptor antagonists, but not affected by the mast cell stabilizer sodium cromoglycate (1 mM). These results demonstrate that histamine causes direct relaxation of small adrenal cortical arteries, which is largely mediated by endothelial NO and prostaglandins via H1 receptors. The potential role of histamine in linking adrenal vascular events and steroid secretion requires further investigation.

Sign in / Sign up

Export Citation Format

Share Document