scholarly journals SAT-306 Muscarinic and Adrenergic Receptor Cooperativity in a Human Adrenocortical Carcinoma Cell Line

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Latha Malaiyandi ◽  
Alice Meyer ◽  
Nuntida Surachaicharn ◽  
Dominic Pelchat ◽  
Annette Gilchrist ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Calcium Oscillations ◽  
Binding Assays ◽  
Steroid Synthesis ◽  
M3 Receptors ◽  
Aldosterone Production ◽  
Autonomic Receptors

Abstract The role of autonomic receptors in the regulation of the adrenal cortex is poorly understood. We recently showed that activation of M3 muscarinic receptors stimulates intracellular calcium oscillations, aldosterone production, and expression of CYP11B2 (1). The present study explores the relationship between muscarinic and adrenergic receptors in corticosteroid production. Using live-cell fluorescence imaging of HAC15 adrenocortical cells with the calcium-sensitive probe Fluo-4, we have shown that stimulation of adrenergic receptors with the endogenous, non-selective adrenergic agonist norepinephrine (10μM) enhances intracellular Ca2+ oscillations caused by the cholinergic agonist carbachol (1μM). However, Ca2+ is not affected by norepinephrine alone. Adrenergic enhancement of carbachol-induced Ca2+ oscillations is blocked by the ⍺ adrenergic receptor antagonist phentolamine, but not by the β adrenergic receptor antagonist propanolol. Specifically, ⍺2 and β2 antagonists (such as yohimbine and butoxamine, respectively) significantly suppressed the norepinephrine effect, but ⍺1 and β1 antagonists (such as tamsulosin and metoprolol, respectively) had no effect. RT qPCR identified ⍺2A receptors as the most abundant adrenergic receptor in HAC15 cells. Saturation experiments using 3H-NMS and 3H-Rauwolscine confirmed the presence of muscarinic M2 and M3 receptors as well as ⍺2A receptors. Using competition radiolabeled binding assays we explored the cooperation between M2/M3 and ⍺2A adrenergic receptors. Our results suggest that autonomic regulation of intracellular Ca2+ depends on an interplay of M3 and ⍺2A receptors. Additional experiments will use ELISA methods to determine the functional impact of autonomic receptor cooperativity on steroid synthesis and secretion. References: (1) Malaiyandi et al., Mol Cell Endocrinol. 2018 478: 1-9.

Role of supraspinal and spinal α1-adrenergic receptor subtypes in micturition reflex in conscious rats

2010 ◽  
Vol 299 (4) ◽  
pp. F785-F791 ◽  
Author(s):  
Masaru Yoshizumi ◽  
Kazumasa Matsumoto-Miyai ◽  
Akihiko Yonezawa ◽  
Masahito Kawatani
Keyword(s):  
Spinal Cord ◽  
Receptor Antagonist ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Intrathecal Injection ◽  
Receptor Subtypes ◽  
Lumbosacral Spinal Cord ◽  
Micturition Reflex ◽  
Conscious Rats

α1-Adrenergic receptor subtypes are widely distributed in the central nervous system and are involved in autonomic functions such as micturition. We investigated the presence and the role of supraspinal and/or spinal α1-adrenergic receptors in modulating the micturition reflex in conscious female Wistar rats. The expression of α1-adrenergic receptor subtypes in rat brain and lumbosacral spinal cord was studied using RT-PCR. Continuous-infusion cystometrograms were obtained in conscious rats, and α1-adrenergic receptor antagonists were administered via intracerebroventricular or intrathecal routes. The mRNA expression of α1A-, α1B-, and α1D-adrenergic receptors was detected in rat brain (midbrain and pons) and lumbosacral spinal cord (dorsal and ventral parts of spinal cord). In addition, intracerebroventricular injection of the α1-adrenergic receptor antagonist tamsulosin (1–10 μg), the selective α1A-adrenergic receptor antagonist silodosin (1–10 μg), and the selective α1D-adrenergic receptor antagonist BMY 7378 (1–10 μg) significantly prolonged the intercontraction interval (ICI) but did not alter maximum voiding pressure (MVP). Although intrathecal injection of BMY 7378 (0.0001–10 μg) did not affect ICI, tamsulosin and silodosin prolonged ICI in a dose-dependent manner. MVP was significantly reduced by intrathecal injection of tamsulosin (10 μg) but not by silodosin or BMY 7378 (0.0001–10 μg). Supraspinal α1A- and α1D-adrenergic receptors are apparently important for the regulation of reflex-bladder activity in conscious rats. Noradrenergic projection from the brain stem to the lumbosacral spinal cord may promote the afferent limb rather than the efferent limb of the micturition reflex pathway via α1A-adrenergic receptors.

Inhibition of Glutamatergic Synaptic Input to Spinal Lamina IIo Neurons by Presynaptic α2-Adrenergic Receptors

2002 ◽  
Vol 87 (4) ◽  
pp. 1938-1947 ◽  
Author(s):  
Yu-Zhen Pan ◽  
De-Pei Li ◽  
Hui-Lin Pan
Keyword(s):  
Receptor Antagonist ◽  
Synaptic Input ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Dorsal Root ◽  
Primary Afferents ◽  
Noradrenergic System ◽  
Analgesic Action ◽  
Adrenergic Agonists ◽  
Excitatory Synaptic Input

Activation of spinal α2-adrenergic receptors by the descending noradrenergic system and α2-adrenergic agonists produces analgesia. However, the sites and mechanisms of the analgesic action of spinally administered α2-adrenergic receptor agonists such as clonidine are not fully known. The dorsal horn neurons in the outer zone of lamina II (lamina IIo) are important for processing nociceptive information from C-fiber primary afferents. In the present study, we tested a hypothesis that activation of presynaptic α2-adrenergic receptors by clonidine inhibits the excitatory synaptic input to lamina IIo neurons. Whole cell voltage-clamp recordings were performed on visualized lamina IIo neurons in the spinal cord slice of rats. The miniature excitatory postsynaptic currents (mEPSCs) were recorded in the presence of tetrodotoxin, bicuculline, and strychnine. The evoked EPSCs were obtained by electrical stimulation of the dorsal root entry zone or the attached dorsal root. Both mEPSCs and evoked EPSCs were abolished by application of 6-cyano-7-nitroquinoxaline-2,3-dione. Clonidine (10 μM) significantly decreased the frequency of mEPSCs from 5.8 ± 0.9 to 2.7 ± 0.6 Hz (means ± SE) without altering the amplitude and the decay time constant of mEPSCs in 25 of 27 lamina IIo neurons. Yohimbine (2 μM, an α2-adrenergic receptor antagonist), but not prazosin (2 μM, an α1-adrenergic receptor antagonist), blocked the inhibitory effect of clonidine on the mEPSCs. Clonidine (1–20 μM, n = 8) also significantly attenuated the peak amplitude of evoked EPSCs in a concentration-dependent manner. The effect of clonidine on evoked EPSCs was abolished in the presence of yohimbine ( n = 5). These data suggest that clonidine inhibits the excitatory synaptic input to lamina IIo neurons through activation of α2-adrenergic receptors located on the glutamatergic afferent terminals. Presynaptic inhibition of glutamate release from primary afferents onto lamina IIoneurons likely plays an important role in the analgesic action produced by activation of the descending noradrenergic system and α2-adrenergic agonists.

scholarly journals Role of beta-adrenergic receptor subtypes in pig uterus contractility with inflammation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Barbara Jana ◽  
Jarosław Całka
Keyword(s):  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Domestic Animals ◽  
Inhibitory Effect ◽  
Receptor Subtypes ◽  
Beta Adrenergic Receptor ◽  
Pharmacological Modulation ◽  
Uterine Inflammation ◽  
Myometrial Contractility

AbstractUterine inflammation is a very common and serious condition in domestic animals. To development and progression of this pathology often lead disturbances in myometrial contractility. Participation of β1-, β2- and β3-adrenergic receptors (ARs) in noradrenaline (NA)-influenced contractility of the pig inflamed uterus was studied. The gilts of SAL- and E.coli-treated groups were administered saline or E.coli suspension into the uterine horns, respectively. Laparotomy was only done in the CON group. Compared to the period before NA administration, this neurotransmitter reduced the tension, amplitude and frequency in uterine strips of the CON and SAL groups. In the E.coli group, NA decreased the amplitude and frequency, and these parameters were lower than in other groups. In the CON, SAL and E.coli groups, β1- and β3-ARs antagonists in more cases did not significantly change and partly eliminated NA inhibitory effect on amplitude and frequency, as compared to NA action alone. In turn, β2-ARs antagonist completely abolished NA relaxatory effect on these parameters in three groups. Summarizing, NA decreases the contractile amplitude and frequency of pig inflamed uterus via all β-ARs subtypes, however, β2-ARs have the greatest importance. Given this, pharmacological modulation of particular β-ARs subtypes can be used to increase inflamed uterus contractility.

scholarly journals The Alpha-1 Adrenergic Receptor Antagonist Prazosin Reduces Binge-Like Eating in Rats

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1569
Author(s):  
Callum Hicks ◽  
Valentina Sabino ◽  
Pietro Cottone
Keyword(s):  
Receptor Antagonist ◽  
Adrenergic Receptor ◽  
Fixed Ratio ◽  
Progressive Ratio ◽  
Noradrenergic System ◽  
Palatable Food ◽  
Schedule Of Reinforcement ◽  
Male Wistar Rats

Background: Binge-eating disorder is a pervasive addiction-like disorder that is defined by excessive and uncontrollable consumption of food within brief periods of time. The aim of the current study was to examine the role of the brain noradrenergic system in binge-like eating through the use of the alpha-1 adrenergic receptor antagonist prazosin. Methods: For this purpose, we employed a limited access model whereby male Wistar rats were allowed to nosepoke for either chow (Chow rats) or a sugary, highly palatable food (Palatable rats) for 1 h/day. The effects of prazosin (0, 0.5, 1 and 2 mg/kg, i.p.) were tested in a fixed ratio 1 (FR1) and progressive ratio (PR) schedule of reinforcement. Results: The results show that prazosin preferentially reduced the responses for palatable food in a FR1 reinforcement schedule; when tested in a PR schedule of reinforcement, prazosin increased breakpoint in both Chow and Palatable rats, but more potently and more efficaciously in the latter. Our results suggest that prazosin treatment preferentially increased the motivational properties of the palatable diet. Conclusions: The current findings provide the characterization of the effects of prazosin on binge-like eating and offer support to the existing literature showing the important role of the noradrenergic system in addiction-like behavior.

Investigations into the causes of the rise in aldosterone secretion during haemorrhage Part II

1966 ◽  
Vol 250 (767) ◽  
pp. 277-310
Keyword(s):  
Blood Loss ◽  
Constant Infusion ◽  
Necessary Condition ◽  
Posterior Lobe ◽  
Donor Blood ◽  
Aldosterone Secretion ◽  
Steroid Synthesis ◽  
Aldosterone Production ◽  
Secretion Rates

The role of ACTH and of renin as mediators of the stimulating effect of haemorrhage on aldosterone secretion was investigated. The following experiments showed that release of ACTH is not indispensible for the effect: in non-hypophysectomized dogs with intact kidneys, in which the blood ACTH concentration was artificially raised by infusing ACTH , there was still a rise in aldosterone production after blood loss. Hypophysectomy did not abolish or reduce the response, in fact, it increased its frequency of occurrence in dogs in which steroid synthesis was maintained at a submaximal level by a constant infusion of ACTH . Another group of studies demonstrated that the release of renin is also not a necessary condition for the rise in aldosterone production after bleeding; dogs in which both kidneys had been removed, but the pituitary left intact, responded to bleeding by a rise in aldosterone secretion of the same magnitude as normal dogs. However, in the simultaneous absence of kidneys and pituitary gland aldosterone production did not rise after bleeding although the basic conditions for synthesis of steroids were provided by a constant infusion of ACTH . On the contrary, severe falls in steroid secretion rates were the rule. These falls were attributed to the fact that hypophysectomized-nephrectomized dogs often reacted to blood loss with collapse of the circulation, and it was possible to argue that this collapse, and not the absence of kidney and pituitary, might have prevented the rise in aldosterone secretion. Attempts were therefore made to improve the circulation by supplying pressor substances known to be released in haemorrhage: of these noradrenaline did not improve the tolerance to haemorrhage, angiotensin improved it only very slightly, but prolonged infusions of extracts of posterior lobe restored it nearly to normal. In some of these experiments, the post-haemorrhage fall in aldosterone secretion was also prevented, but a rise was never seen. Aldosterone secretion of the hypophysectomized-nephrectomized dog was stimulated by infusion of large volumes of donor blood obtained from dogs with intact kidneys which presumably contains renin, but not of blood from nephrectomized donors. No evidence was obtained for the existence of agents other than ACTH and angiotensin as mediators of the stimulating effect of haemorrhage on aldosterone secretion. Furthermore, these two agents could fully replace each other, as shown by the finding that the effect of haemorrhage was not diminished by either nephrectomy or hypophysectomy alone.

scholarly journals Noradrenergic control of central oxytocin release during lactation in rats

1998 ◽  
Vol 274 (3) ◽  
pp. E453-E458 ◽  
Author(s):  
Steven L. Bealer ◽  
William R. Crowley
Keyword(s):  
Cerebrospinal Fluid ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Additional Experiment ◽  
Adrenergic Agonist ◽  
Magnocellular Nuclei ◽  
Artificial Cerebrospinal Fluid ◽  
Oxytocin Release ◽  
Stimulation Of

Noradrenergic systems regulate the systemic release of oxytocin (OT) in lactating rats. However, a role for norepinephrine (NE) in release of OT within the magnocellular nuclei during suckling has not been established. These studies were designed to determine 1) if suckling induces NE release in the supraoptic (SON) and paraventricular (PVN) nuclei of conscious rats and 2) the role of NE in the central, intranuclear release of OT within these nuclei. Female Holtzman rats were implanted with microdialysis probes adjacent to the PVN or SON on lactation days 8- 12. The following day, the pups were isolated from the dams for 4 h. Microdialysis probes were perfused with artificial cerebrospinal fluid (ACSF) or with ACSF containing an α- or a β-adrenergic receptor antagonist. Dialysate was collected before, during, and after suckling and analyzed for NE or OT. In an additional experiment, an α- or β-adrenergic agonist was administered via the microdialysis probes into the PVN in nonsuckled, lactating rats. Extracellular NE increased in the PVN during suckling but was not detectable in the SON. OT concentrations in dialysates from the PVN and SON significantly increased during suckling. Blockade of either α- (in both PVN and SON) or β- (PVN) adrenergic receptors prevented the suckling-induced increase in central OT release. OT release was increased in nonsuckled, lactating rats by central application of either an α- or β-adrenergic agonist. These data demonstrate that intranuclear NE release is increased in the PVN by suckling and that subsequent stimulation of both α- and β-noradrenergic receptors mediates intranuclear OT release.

scholarly journals Propranolol, but not naloxone, enhances spinal reflex bladder activity and reduces pudendal inhibition in cats

2015 ◽  
Vol 308 (1) ◽  
pp. R42-R49 ◽  
Author(s):  
Marc J. Rogers ◽  
Zhiying Xiao ◽  
Bing Shen ◽  
Jicheng Wang ◽  
Zeyad Schwen ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Nerve Stimulation ◽  
Adrenergic Receptor ◽  
Bladder Capacity ◽  
Spinal Reflex ◽  
Saline Control ◽  
Tibial Nerve Stimulation ◽  
Bladder Activity ◽  
Propranolol Treatment

This study examined the role of β-adrenergic and opioid receptors in spinal reflex bladder activity and in the inhibition induced by pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS). Spinal reflex bladder contractions were induced by intravesical infusion of 0.25% acetic acid in α-chloralose-anesthetized cats after an acute spinal cord transection (SCT) at the thoracic T9/T10 level. PNS or TNS at 5 Hz was applied to inhibit these spinal reflex contractions at 2 and 4 times the threshold intensity (T) for inducing anal or toe twitch, respectively. During a cystrometrogram (CMG), PNS at 2T and 4T significantly ( P < 0.05) increased bladder capacity from 58.0 ± 4.7% to 85.8 ± 10.3% and 96.5 ± 10.7%, respectively, of saline control capacity, while TNS failed to inhibit spinal reflex bladder contractions. After administering propranolol (3 mg/kg iv, a β1/β2-adrenergic receptor antagonist), the effects of 2T and 4T PNS on bladder capacity were significantly ( P < 0.05) reduced to 64.5 ± 9.5% and 64.7 ± 7.3%, respectively, of the saline control capacity. However, the residual PNS inhibition (about 10% increase in capacity) was still statistically significant ( P < 0.05). Propranolol treatment also significantly ( P = 0.0019) increased the amplitude of bladder contractions but did not change the control bladder capacity. Naloxone (1 mg/kg iv, an opioid receptor antagonist) had no effect on either spinal reflex bladder contractions or PNS inhibition. At the end of experiments, hexamethonium (10 mg/kg iv, a ganglionic blocker) significantly ( P < 0.05) reduced the amplitude of the reflex bladder contractions. This study indicates an important role of β1/β2-adrenergic receptors in pudendal inhibition and spinal reflex bladder activity.

scholarly journals Heat and α1-adrenergic responsiveness in human skeletal muscle feed arteries: the role of nitric oxide

2012 ◽  
Vol 113 (11) ◽  
pp. 1690-1698 ◽  
Author(s):  
Stephen J. Ives ◽  
Robert H. I. Andtbacka ◽  
Sun Hyung Kwon ◽  
Yan-Ting Shiu ◽  
Ting Ruan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Human Skeletal Muscle ◽  
Bovine Endothelial Cells ◽  
No Bioavailability ◽  
Feed Arteries ◽  
Skeletal Muscle Feed Arteries

Increased local temperature exerts a sympatholytic effect on human skeletal muscle feed arteries. We hypothesized that this attenuated α1-adrenergic receptor responsiveness may be due to a temperature-induced increase in nitric oxide (NO) bioavailability, thereby reducing the impact of the α1-adrenergic receptor agonist phenylephrine (PE). Thirteen human skeletal muscle feed arteries were harvested, and wire myography was used to generate PE concentration-response curves at 37°C and 39°C, with and without the NO synthase (NOS) inhibitor NG-monomethyl-l-arginine (l-NMMA). A subset of arteries ( n = 4) were exposed to 37°C or 39°C, and the protein content of endothelial NOS (eNOS) and α1-adrenergic receptors was determined by Western blot analysis. Additionally, cultured bovine endothelial cells were exposed to static or shear stress conditions at 37°C and 39°C and assayed for eNOS activation (phosphorylation at Ser1177), eNOS expression, and NO metabolites [nitrate + nitrite (NOx)]. Maximal PE-induced vasocontraction (PEmax) was lower at 39°C than at 37°C [39 ± 10 vs. 84 ± 30% maximal response to 100 mM KCl (KClmax)]. NO blockade restored vasocontraction at 39°C to that achieved at 37°C (80 ± 26% KClmax). Western blot analysis of the feed arteries revealed that heating increased eNOS protein, but not α1-adrenergic receptors. Heating of bovine endothelial cells resulted in greater shear stress-induced eNOS activation and NOx production. Together, these data reveal for the first time that, in human skeletal muscle feed arteries, NO blockade can restore the heat-attenuated α1-adrenergic receptor-mediated vasocontraction and implicate endothelium-derived NO bioavailability as a major contributor to heat-induced sympatholysis. Consequently, these findings highlight the important role of vasodilators in modulating the vascular response to vasoconstrictors.

Interaction between prolactin and catecholamines on hypothalamic GnRH release in vitro

1996 ◽  
Vol 151 (2) ◽  
pp. 269-275 ◽  
Author(s):  
A E Calogero ◽  
N Burrello ◽  
A M Ossino ◽  
R F A Weber ◽  
R D'Agata
Keyword(s):  
Receptor Antagonist ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Experimental Conditions ◽  
Adrenergic Mechanism ◽  
Gnrh Release ◽  
Β Adrenergic Receptors

Abstract Brain catecholamines have been implicated in the regulation of gonadotrophin release. It has been recently reported that noradrenaline (NA), applied within the hypothalamic paraventricular nucleus, suppresses the pulsatile release of LH in the rat through a corticotrophin-releasing hormone (CRH)-dependent mechanism. Prolactin (PRL) is also able to suppress hypothalamic GnRH release following activation of the CRH-releasing neurone. Given that PRL stimulates the release of NA from hypothalamic explants and that NA stimulates the release of hypothalamic CRH, we hypothesized that this neurotransmitter may be involved in the intrahypothalamic neuroendocrine circuit mediating the inhibitory effects of PRL on GnRH release. To test this hypothesis, we evaluated the effects of PRL on GnRH release in the presence of α- or β-adrenergic receptor antagonists using a static hypothalamic organ culture system which enabled us to evaluate immunoreactive GnRH (iGnRH) release from individually incubated, longitudinally halved hypothalami. As previously shown, PRL at a concentration of 100 nm inhibited basal iGnRH release by about 35%. Phentolamine, a non-selective α-adrenergic receptor antagonist, prazosin, an α1-receptor antagonist, and yohimbine, an α2-receptor antagonist, overcame the inhibitory effect of PRL on iGnRH release in a concentration-dependent fashion. In contrast, propranolol, a non-selective β-adrenergic receptor antagonist, atenolol, a β1-receptor antagonist, and ICI-118,551, a β2-receptor antagonist, had no effect. None of these compounds had any effect on basal iGnRH release. These findings suggested that an α-adrenergic mechanism is involved in the suppressive effects of PRL on GnRH release. Since the activation of α-adrenergic receptors increases hypothalamic CRH release, we evaluated whether PRL stimulates CRH release via an α-adrenergic mechanism. PRL stimulated basal CRH release by about twofold and this effect was inhibited by phentolamine in a concentration-dependent fashion. In conclusion, α-, but not β-, adrenergic receptors mediate the inhibitory effects of PRL on GnRH release in vitro. We speculate that, at least under these experimental conditions, PRL inhibits GnRH release through an α-adrenergic mechanism which activates the CRH-secreting neurone. Journal of Endocrinology (1996) 151, 269–275

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