Adrenergic Receptor Signaling Research Articles

Cross-talk between metabotropic glutamate receptor 7 and beta adrenergic receptor signaling at cerebrocortical nerve terminals

The co-existence of presynaptic G protein coupled receptors, GPCRs, has received little attention, despite the fact that interplay between the signaling pathways activated by such receptors may affect the neurotransmitter release. Using immunocytochemistry and immuhistochemistry we show that mGlu7 and β-adrenergic receptors are co-expressed in a sub-population of cerebrocortical nerve terminals. mGlu7 receptors readily couple to pathways that inhibit glutamate release. We found that when mGlu7 receptors are also coupled to pathways that enhance glutamate release by prolonged exposure to agonist, and β-adrenergic receptors are also activated, a cross-talk between their signaling pathways occurs that affect the overall release response. This interaction is the result of mGlu7 receptors inhibiting the adenylyl cyclase activated by β adrenergic receptors. Thus, blocking Gi/o proteins with pertussis toxin provokes a further increase in release after receptor co-activation which is also observed after activating β-adrenergic receptor signaling pathways downstream of adenylyl cyclase with the cAMP analog Sp8Br or 8pCPT-2-OMe-cAMP (a specific activator of the guanine nucleotide exchange protein directly activated by cAMP, EPAC). Co-activation of mGlu7 and β-adrenergic receptors also enhances PLC-dependent accumulation of IP1 and the translocation of the active zone protein Munc13-1 to the membrane, indicating that release potentiation by these receptors involves the modulation of the release machinery.

Phosphorylation of the Na + ‐H + Exchanger Isoform 1 Initiated by α 1 ‐Adrenergic Receptor Signaling Regulates Cell Growth and Movement

α1-adrenergic receptor signaling has been implicated in cancer progression through the stimulation of cell proliferation, cell migration and cell invasion. Conversely, blocking α1-adrenergic receptor signaling decreases tumor formation in animal models. The α1-adrenergic receptor is a G protein-coupled receptor that initiates a complex series of intracellular signaling events. Receptor activation stimulates phospholipases, protein kinases, and intracellular calcium release. The α1-adrenergic receptor can activate three distinct protein kinases that phosphorylate NHE1 in four different locations. These kinases and the locations they phosphorylate are: 1) Rock which phosphorylates NHE1 at T653, 2) Rsk which phosphorylates NHE1 at S703, and 3) Erk which phosphorylates NHE1 at both S770 and S771. To evaluate the role of each of these phosphorylation sites in the regulation of cellular function we have created a series of cell lines each expressing human NHE1 with one of the phosphorylation sites mutated to an alanine, thus removing that ability for NHE1 to be phosphorylated at that location. We will evaluate each of these cell lines, PSN T653A, PSN S703A, PSN S770A, and PSN S771A to determine the role of each phosphorylation site. We will use an XTT assay to evaluate cell proliferation, AlexaFluor 488 phalloidin to evaluate stress fiber formation, and ibidi wound healing inserts to evaluate cell migration.

Insulin induces IRS2-dependent and GRK2-mediated β2AR internalization to attenuate βAR signaling in cardiomyocytes

The counter-regulatory effects of insulin and catecholamines on carbohydrate and lipid metabolism are well studied, whereas the details of insulin regulation of β adrenergic receptor (βAR) signaling pathway in heart remain unknown. Here, we characterize a novel signaling pathway of insulin receptor (IR) to G protein-coupled receptor kinase 2 (GRK2) in the heart. Insulin stimulates recruitment of GRK2 to β2AR, which induces β2AR phosphorylation at the GRK sites of serine 355/356 and subsequently β2AR internalization. Insulin thereby suppresses βAR-induced cAMP-PKA activities and contractile response in neonatal and adult mouse cardiomyocytes. Deletion of insulin receptor substrate 2 (IRS2) disrupts the complex of IR and GRK2, which attenuates insulin-mediated β2AR phosphorylation at the GRK sites and β2AR internalization, and the counter-regulation effects of insulin on βAR signaling. These data indicate the requirements of IRS2 and GRK2 for insulin to stimulate counter-regulation of βAR via β2AR phosphorylation and internalization in cardiomyocytes.

Tailoring therapy for heart failure: the pharmacogenomics of adrenergic receptor signaling

Heart failure is one of the leading causes of mortality in Western countries, and β-blockers are a cornerstone of its treatment. However, the response to these drugs is variable among individuals, which might be explained, at least in part, by genetic differences. Pharmacogenomics is the study of genetic contributions to drug response variability in order to provide evidence for a tailored therapy in an individual patient. Several studies have investigated the pharmacogenomics of the adrenergic receptor system and its role in the context of the use of β-blockers in treating heart failure. In this review, we will focus on the most significant polymorphisms described in the literature involving adrenergic receptors and adrenergic receptor-related proteins, as well as genetic variations influencing β-blocker metabolism.

Abstract 641: Renal Denervation does not Lower Blood Pressure in Spontaneously Hypertensive Rats Treated with a Beta-1 Adrenergic Receptor Antagonist.

We have used the SHR as an animal model to understand how renal denervation (RDN) lowers blood pressure. In order to determine how concomitant antihypertensive drug therapy could affect the blood pressure response to RDN, we performed RDN both before and after chronic (several days) treatment via the drinking water with the selective alpha-1 adrenergic antagonist prazosin and the selective beta-1 adrenergic antagonist atenolol. In the presence of prazosin treatment, RDN (n=7) significantly (p<0.05) lowered mean arterial pressure (MAP) compared to sham operated (SO; n=6) SHR (Δ=–4.0±1.7mmHg in RDN-SHR vs +1.5±1.3 in SO-SHR). Subsequent addition of atenolol during prazosin treatment reduced MAP significantly in both groups, but MAP in SO-SHR fell to the same level as in RDN-SHR, i.e. the antihypertensive effect of RDN was lost. After discontinuation of all drug treatment, the change in MAP from pre-treatment baseline was –7.7±3.5mmHg in RDN-SHR and +3.0±4.0mmHg in SO-SHR, p=0.06). To test whether the BP response to RDN would be lost during blockade of beta-1 adrenergic receptors alone, we performed RDN in SHR (n=5) pre-treated with atenolol. Atenolol alone significantly reduced MAP (Δ=-20.7±2.5mmHg). Steady-state MAP was not further reduced by RDN (Δ=+2.1±0.9mmHg). When atenolol was withdrawn MAP rose but remained reduced from baseline (Δ= -9.5±0.9mmHg). This magnitude of BP reduction is comparable to what we have previously observed after RDN in untreated SHR. In summary, in SHR RDN does not lower BP in the presence of an effective antihypertensive dose of a beta-1 antagonist. This indicates that RDN is reducing BP in SHR by interrupting a mechanism also affected by beta-1 adrenergic receptor signaling. Although further investigation is necessary, the data suggest that possibility that patients on clinically effective antihypertensive doses of beta-blockers may not exhibit a good response to RDN.

Targeting α- and β-Adrenergic Receptors Differentially Shifts Th1, Th2, and Inflammatory Cytokine Profiles in Immune Organs to Attenuate Adjuvant Arthritis.

The sympathetic nervous system (SNS) regulates host defense responses and restores homeostasis. SNS-immune regulation is altered in rheumatoid arthritis (RA) and rodent models of RA, characterized by nerve remodeling in immune organs and defective adrenergic receptor (AR) signaling to immune cell targets. The SNS typically promotes or suppresses inflammation via α- and β2-AR activation, respectively, and indirectly drives humoral immunity by blocking Th1 cytokine secretion. Here, we investigate how β2-AR stimulation and/or α-AR blockade at disease onset affects disease pathology and cytokine profiles in relevant immune organs from male Lewis rats with adjuvant-induced arthritis (AA). Rats challenged to induce AA were treated with terbutaline (TERB), a β2-AR agonist (600 μg/kg/day) and/or phentolamine (PHEN), an α-AR antagonist (5.0 mg/kg/day) or vehicle from disease onset through severe disease. We report that in spleen, mesenteric (MLN) and draining lymph node (DLN) cells, TERB reduces proliferation, an effect independent of IL-2. TERB also fails to shift T helper (Th) cytokines from a Th1 to Th2 profile in spleen and MLN (no effect on IFN-γ) and DLN (greater IFN-γ) cells. In splenocytes, TERB, PHEN, and co-treatment (PT) promotes an anti-inflammatory profile (greater IL-10) and lowers TNF-α (PT only). In DLN cells, drug treatments do not affect inflammatory profiles, except PT, which raised IL-10. In MLN cells, TERB or PHEN lowers MLN cell secretion of TNF-α or IL-10, respectively. Collectively, our findings indicate disrupted β2-AR, but not α-AR signaling in AA. Aberrant β2-AR signaling consequently derails the sympathetic regulation of lymphocyte expansion, Th cell differentiation, and inflammation in the spleen, DLNs and MLs that is required for immune system homeostasis. Importantly, this study provides potential mechanisms through which reestablished balance between α- and β2-AR function in the immune system ameliorates inflammation and joint destruction in AA.

Role of adrenergic receptor signaling pathway in colorectal cancer

Role of adrenergic receptor signaling pathway in colorectal cancer

β-Arrestin1–Biased β 1 -Adrenergic Receptor Signaling Regulates MicroRNA Processing

MicroRNAs (miRs) are small, noncoding RNAs that function to post-transcriptionally regulate gene expression. First transcribed as long primary miR transcripts (pri-miRs), they are enzymatically processed in the nucleus by Drosha into hairpin intermediate miRs (pre-miRs) and further processed in the cytoplasm by Dicer into mature miRs where they regulate cellular processes after activation by a variety of signals such as those stimulated by β-adrenergic receptors (βARs). Initially discovered to desensitize βAR signaling, β-arrestins are now appreciated to transduce multiple effector pathways independent of G-protein-mediated second messenger accumulation, a concept known as biased signaling. We previously showed that the β-arrestin-biased βAR agonist, carvedilol, activates cellular pathways in the heart. Here, we tested whether carvedilol could activate β-arrestin-mediated miR maturation, thereby providing a novel potential mechanism for its cardioprotective effects. In human cells and mouse hearts, carvedilol upregulates a subset of mature and pre-miRs, but not their pri-miRs, in β1AR-, G-protein-coupled receptor kinase 5/6-, and β-arrestin1-dependent manner. Mechanistically, β-arrestin1 regulates miR processing by forming a nuclear complex with hnRNPA1 and Drosha on pri-miRs. Our findings indicate a novel function for β1AR-mediated β-arrestin1 signaling activated by carvedilol in miR biogenesis, which may be linked, in part, to its mechanism for cell survival.

Abstract 628: Early Life Stress Exacerbates The Adrenergic Receptor Subtypes Mrna Expression In The Kidney

Maternal separation (MS) in rodents is a model of human chronic behavioral stress during early life. Previously we have shown that renal sympathetic system is sensitized in adult MS rats. Accordingly, we found that reduced glomerular filtration rate in intact MS rats was normalized after bilateral renal denervation (DnX). The aims of this study were to test the mRNA expression of adrenergic receptor (AR) subtypes in intact and DnX renal cortex and renal vessels. Also, to test the levels of mediators related to the alpha (1,4,5-trisphosphate, IP3) and beta (adenosine-3′,5′-cyclic monophosphate, cAMP) AR signaling pathways. MS was performed in WKY by separating approx half of the male pups from the dam 3 hr a day from days 2-14 of life. Renal tissue from 12 weeks old rats was harvested and snapped frozen. RT-PCR was performed using primers for ARs and IP3 receptor 1 and 2 and mRNA levels. cAMP was determined in renal cortex homogenates by ELISA. IP3 receptor mRNA expression was not different between MS and control rats in intact cortex, Dnx cortex or kidney vessels. cAMP was increased in intact renal cortex of MS rats compared to control (2.37±0.23 vs. 1.55±0.0.24 pmol/mg protein, respectively, p<0.05). Relative mRNA expression (2 - ΔΔ ct ) of α1a, α1b, α1d and α2b were not different in intact cortex from control and MS rats, while Dnx did not have any significant effect. However, α2c AR was increased in intact renal cortex from MS rats compared to control rats (4.5±1.2 vs. 1.8±0.3 2 - ΔΔ ct , p<0.05). DnX significantly reduced α2c mRNA expression in renal cortex from MS and control rats (0.9±0.2 and 0.5±0.1 2 - ΔΔ ct , p<0.05 vs. intact cortex). Relative mRNA expression of α1a, α1b, α1d, α2b and α2c were significantly increased in renal vessels tissue from MS rats compared to control rats (p<0.05). We conclude that enhanced renal mRNA expression of ARs, especially α2c, may be a key mechanisms contributing to the lower glomerular filtration capacity in MS rats. Distinctive pharmacodynamic properties of α2c ARs suggest that they may be attractive targets for therapeutic intervention in case of exposition to early life stress.

Abstract 299: Simultaneous Cardiac And Adrenal Small Molecule GPCR-Gβ? Inhibition Halts The Progression Of Pressure Overload Heart Failure

Heart failure (HF) is a progressive disease with rapidly increasing rates of morbidity and mortality. Elevated sympathetic nervous system activity, a salient feature of HF progression, leads to pathologic attenuation and desensitization of β-adrenergic receptors (β-ARs) due in part to Gβγ-mediated signaling. In the current study, we assessed the hypothesis that the small molecule Gβγ inhibitor “gallein” is salutary in treating pre-existing HF in a clinically relevant model (pressure-overload HF model of mouse transverse aortic constriction (TAC)) by simultaneously normalizing adrenergic receptor signaling in the heart and the adrenal gland. Four weeks post-TAC, mice received daily i.p. injections of vehicle or gallein for eight weeks (n=6-8 per group). Serial echocardiography was performed through out the study. At the end of the experiment, hemodynamic studies were performed, mice were sacrificed, blood, heart, and adrenal glands were harvested for further analysis. Gallein treatment improved survival and cardiac function and reduced cardiac hypertrophy, remodeling, and fetal genes expression in TAC mice. On the molecular level, gallein recovered membrane β-AR density and attenuated GRK2-PI3Kγ membrane recruitment, and Akt-GSK-3β signaling in TAC hearts. A salutary adrenal effect of gallein was obtained in cultured mice adrenal glands and human pheochromocytoma tissue (n=3), where direct gallein treatment restored α2-AR feedback inhibitory function and concurrently reduced catecholamine production. Moreover, gallein treatment attenuated adrenal hypertrophy in TAC mice and downregulated tyrosine hydroxylase and chromogranin A protein expression in adrenal glands from TAC mice and cultured pheochromocytoma tissue as well. In summary, our data suggest gallein as a systemic pharmacologic therapy with substantial therapeutic benefit in HF by simultaneously normalizing pathologic Gβγ-GRK2 signaling and recovering AR signaling in both the heart and the adrenal gland. In the heart, gallein mediated attenuation of cardiac remodeling probably involves inhibiting GRK2-PI3K-Akt signaling. Our data also suggest a role for small molecule Gβγ inhibition in other diseases of elevated catecholamine release, such as pheochromocytoma.

PKA-independent activation of If by cAMP in mouse sinoatrial myocytes

Hyperpolarization-activated, cyclic nucleotide-sensitive (HCN4) channels produce the “funny current,” If, which contributes to spontaneous pacemaking in sinoatrial myocytes (SAMs). The C-terminus of HCN channels inhibits voltage-dependent gating, and cAMP binding relieves this “autoinhibition.” We previously showed 1) that autoinhibition in HCN4 can be relieved in the absence of cAMP in some cellular contexts and 2) that PKA is required for β adrenergic receptor (βAR) signaling to HCN4 in SAMs. Together, these results raise the possibility that native HCN channels in SAMs may be insensitive to direct activation by cAMP. Here, we examined PKA-independent activation of If by cAMP in SAMs. We observed similar robust activation of If by exogenous cAMP and Rp-cAMP (an analog than cannot activate PKA). Thus PKA-dependent βAR-to-HCN signaling does not result from cAMP insensitivity of sinoatrial HCN channels and might instead arise via PKA-dependent limitation of cAMP production and/or cAMP access to HCN channels in SAMs.

Adenylyl Cyclase Anchoring by a Kinase Anchor Protein AKAP5 (AKAP79/150) Is Important for Postsynaptic β-Adrenergic Signaling

Recent evidence indicates that the A kinase anchor protein AKAP5 (AKAP79/150) interacts not only with PKA but also with various adenylyl cyclase (AC) isoforms. However, the physiological relevance of AC-AKAP5 binding is largely unexplored. We now show that postsynaptic targeting of AC by AKAP5 is important for phosphorylation of the AMPA-type glutamate receptor subunit GluA1 on Ser-845 by PKA and for synaptic plasticity. Phosphorylation of GluA1 on Ser-845 is strongly reduced (by 70%) under basal conditions in AKAP5 KO mice but not at all in D36 mice, in which the PKA binding site of AKAP5 (i.e. the C-terminal 36 residues) has been deleted without affecting AC association with GluA1. The increase in Ser-845 phosphorylation upon β-adrenergic stimulation is much more severely impaired in AKAP5 KO than in D36 mice. In parallel, long term potentiation induced by a 5-Hz/180-s tetanus, which mimics the endogenous θ-rhythm and depends on β-adrenergic stimulation, is only modestly affected in acute forebrain slices from D36 mice but completely abrogated in AKAP5 KO mice. Accordingly, anchoring of not only PKA but also AC by AKAP5 is important for regulation of postsynaptic functions and specifically AMPA receptor activity.

Targeting psychoemotional stress to treat prostate cancer

Targeting psychoemotional stress to treat prostate cancer

Modulation of Purinoceptor mediated Ca2+ signals by β‐adrenergic receptor activation in Salivary Glands

Crosstalk between Ca2+ signaling pathways has been demonstrated to facilitate secretory activity. However it is not known whether such a crosstalk exists between adrenergic receptor signaling pathway and a non‐cholinergic non‐adrenergic (NANC) pathway (purinergic pathway). In this study we use enzymatically isolated mouse parotid acini along with live cell Ca2+ imaging and pharmacological manipulations to assess crosstalk between these two pathways.We showed that [Ca2+]i rises induced by selective activation of P2X4R and P2X7R were potentiated three to eightfold following treatment with the cAMP elevating compounds forskolin, 8‐cpt‐cAMP or 3‐isobutyl‐1‐methylxanthine. Importantly, rises in cAMP levels evoked by β‐adrenergic receptor activation using isoprenalin also resulted in a marked enhancement of P2X‐mediated [Ca2+]i signals.Potentiation of P2X4R‐mediated [Ca2+]i signals following β‐adrenergic receptor activation was likely mediated by PKA because protein kinase inhibitor application in the presence of forskolin or isoprenalin abolished the enhancement of evoked [Ca2+]i signals. Interestingly, application of 2‐Aminoethoxydiphenyl borate during P2X7R stimulation also abolished the enhancement of [Ca2+]i rises following isoprenalin treatment.The results from this study reveal a crosstalk between purinergic and β‐adrenergic signaling pathways and may provide novel targets for construction of therapies for salivary hypofunction patients.

Structure‐Function Relationship and Local Subcellular Signaling using Heart Failure Relevant Molecular Defined Muscle Specific mAKAP Mutants

Beta adrenergic stimulation signals through phosphorylation of downstream proteins such as protein kinase A (PKA). PKA substrate phosphorylation is facilitated through its co localization with its signaling partner by A kinase anchoring proteins (AKAPs). Particularly, mAKAP (muscle selective AKAP) localizes PKA and its target substrates such as phosphodiesterase 4D3 (PDE4D3), ryanodine receptor and protein phosphatase (PP2A). We have recently identified potentially important human mAKAP mutations located within or near key protein binding sites critical to beta adrenergic receptor signaling. Three mutations (P1400S, S2195F and L717V) were cloned for the purpose of comparing whether these substitutions disrupted mAKAP binding to the PKA regulatory subunit RIIα or PDE4D3 binding domain and to understand whether these mutations mediated altered signaling. Interestingly, S2195F, a mutation located in PP2A binding site, showed similar protein expression (p=0.3) to wild type mAKAP, but with a significant increase in binding propensity to RIIα after cell stimulation. This result was corroborated by immunopreciptation (p=0.0003). Consequently, PKA activity showed a significant increase with mAKAP S2195F mutation, as compared to wild type. In conclusion, mAKAP S2195F displayed modified activity and binding propensities and may participate in hypertrophy. This work was supported by NIH (HL085487).

Gene Expression Networks Underlying Ovarian Development in Wild Largemouth Bass (Micropterus salmoides)

BackgroundOocyte maturation in fish involves numerous cell signaling cascades that are activated or inhibited during specific stages of oocyte development. The objectives of this study were to characterize molecular pathways and temporal gene expression patterns throughout a complete breeding cycle in wild female largemouth bass to improve understanding of the molecular sequence of events underlying oocyte maturation.MethodsTranscriptomic analysis was performed on eight morphologically diverse stages of the ovary, including primary and secondary stages of oocyte growth, ovulation, and atresia. Ovary histology, plasma vitellogenin, 17β-estradiol, and testosterone were also measured to correlate with gene networks.ResultsGlobal expression patterns revealed dramatic differences across ovarian development, with 552 and 2070 genes being differentially expressed during both ovulation and atresia respectively. Gene set enrichment analysis (GSEA) revealed that early primary stages of oocyte growth involved increases in expression of genes involved in pathways of B-cell and T-cell receptor-mediated signaling cascades and fibronectin regulation. These pathways as well as pathways that included adrenergic receptor signaling, sphingolipid metabolism and natural killer cell activation were down-regulated at ovulation. At atresia, down-regulated pathways included gap junction and actin cytoskeleton regulation, gonadotrope and mast cell activation, and vasopressin receptor signaling and up-regulated pathways included oxidative phosphorylation and reactive oxygen species metabolism. Expression targets for luteinizing hormone signaling were low during vitellogenesis but increased 150% at ovulation. Other networks found to play a significant role in oocyte maturation included those with genes regulated by members of the TGF-beta superfamily (activins, inhibins, bone morphogenic protein 7 and growth differentiation factor 9), neuregulin 1, retinoid X receptor, and nerve growth factor family.ConclusionsThis study offers novel insight into the gene networks underlying vitellogenesis, ovulation and atresia and generates new hypotheses about the cellular pathways regulating oocyte maturation.

Beta2 adrenergic receptor signaling in CD4+ Foxp3+ regulatory T cells enhances their suppressive function in vitro

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β1 Adrenergic receptor is key to cold- and diet-induced thermogenesis in mice

Brown adipose tissue (BAT) is predominantly regulated by the sympathetic nervous system (SNS) and the adrenergic receptor signaling pathway. Knowing that a mouse with triple β-receptor knockout (KO) is cold intolerant and obese, we evaluated the independent role played by the β(1) isoform in energy homeostasis. First, the 30 min i.v. infusion of norepinephrine (NE) or the β(1) selective agonist dobutamine (DB) resulted in similar interscapular BAT (iBAT) thermal response in WT mice. Secondly, mice with targeted disruption of the β(1) gene (KO of β(1) adrenergic receptor (β(1)KO)) developed hypothermia during cold exposure and exhibited decreased iBAT thermal response to NE or DB infusion. Thirdly, when placed on a high-fat diet (HFD; 40% fat) for 5 weeks, β(1)KO mice were more susceptible to obesity than WT controls and failed to develop diet-induced thermogenesis as assessed by BAT Ucp1 mRNA levels and oxygen consumption. Furthermore, β(1)KO mice exhibited fasting hyperglycemia and more intense glucose intolerance, hypercholesterolemia, and hypertriglyceridemia when placed on the HFD, developing marked non-alcoholic steatohepatitis. In conclusion, the β(1) signaling pathway mediates most of the SNS stimulation of adaptive thermogenesis.

Circadian-Related Heteromerization of Adrenergic and Dopamine D4 Receptors Modulates Melatonin Synthesis and Release in the Pineal Gland

Author SummaryAnimals respond to cycles of light and dark with patterns in sleeping, feeding, body temperature alterations, and other biological functions. The pineal gland translates these light signals received from the retina into a language understandable to the rest of the body through the rhythmic synthesis and release of melatonin in response to the light and dark cycle. This process is controlled by adrenergic receptors. One impressive and mysterious aspect of the system is the rapid ability of rhythmic melatonin production and/or degradation to respond to changes in the cycle. In this study, we demonstrate that part of this response is due to the formation of receptor-receptor complexes (heteromers) between the adrenergic receptors α1B or β1 and the D4 dopamine receptor. Using both biochemical and biophysical methods in transfected cells and in ex vivo tissue we show that dopamine, a neurotransmitter, inhibits adrenergic receptor signaling through these heteromers. This inhibition causes a dramatic decrease in melatonin production of the pineal gland. We postulate that these heteromers provide a rapid feedback mechanism for the neuronal hormone system to modulate circadian-controlled outputs.

Beta-adrenergic Signaling: Complexities and Therapeutic Relevance to Heart Failure

Adrenergic receptor signaling and heart failure are inextricably linked. Beta-adrenergic receptors (β-ARs) serve not only as physiological modulators of heart rate and contractility, they are also primary therapeutic targets of individuals with heart failure as well as many other cardiovascular disorders. In light of these relationships, this short review will focus on the basic pharmacology distinguishing adrenergic receptor subtypes; on receptor subtype selective signaling; the molecular basis of β-AR gene expression; and, delve briefly into genetic variation of β-ARs that represents a potential basis of differential natural history of heart failure progression and that may serve as an underlying basis for therapeutic response.