The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
Robert M. Graham - One of the best experts on this subject based on the ideXlab platform.
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The alpha(1D)-Adrenergic Receptor: cinderella or ugly stepsister.
Molecular pharmacology, 2006Co-Authors: Angela M Finch, Robert M. GrahamAbstract:This Perspective focuses on the alpha(1D)-Adrenergic Receptor (AR), the often neglected sibling of the alpha(1)-AR family. This neglect is due in part to its poor cell-surface expression. However, it has recently been shown that dimerization of the alpha(1D)-AR with either the alpha(1B)-AR or the beta(2)-AR increases alpha(1D)-AR cell-surface expression, and in this issue of Molecular Pharmacology, Hague et al. (p. 45) demonstrate that dimerization of the alpha(1D)-AR with the alpha(1B)-AR not only leads to increased cell-surface expression but also results in the formation of a novel functional entity.
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Synthesis and biological evaluation of bicyclic and tricyclic substituted nortropane derivatives: discovery of a novel selective α1D-Adrenergic Receptor ligand
Bioorganic & Medicinal Chemistry, 2004Co-Authors: Susan J. Mcginty, Angela M Finch, Robert M. Graham, Renate Griffith, John B. BremnerAbstract:Abstract A range of 3,6,6-trisubstituted nortropane derivatives based upon 6 β -phenyltropane-3 β ,6 α -diol have been synthesised from 6 β -hydroxytropinone, including some novel related tricyclic hemi-ketal and tricyclic ketal compounds. Derivatives were assessed for pharmacological affinity and selectivity at α 1 -Adrenergic Receptors, and 6 β -phenyl-8-azabicyclo[3.2.1]octan-3-spiro-2′-(1′,3′-dioxolane)-6-ol, a novel lead compound selective for the alpha 1D -Adrenergic Receptor, is reported.
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Coupling of expressed alpha 1B- and alpha 1D-Adrenergic Receptor to multiple signaling pathways is both G protein and cell type specific.
Molecular Pharmacology, 1993Co-Authors: Dianne M Perez, Mary Beth Deyoung, Robert M. GrahamAbstract:alpha 1-Adrenergic Receptors (ARs) are members of the G protein-coupled Receptor superfamily. alpha 1-AR subtypes mediate the effects of the sympathetic nervous system, especially those involved in cardiac homeostasis. To investigate signal transduction by a novel subtype (alpha 1D), which we recently cloned, and to compare it with that by the previously characterized alpha 1B-AR, we assessed the ability of each subtype to activate polyphosphoinositide (PI) metabolism, cAMP accumulation, and arachidonic acid release in Chinese hamster ovary (CHO) and COS-1 cells expressing these subtypes after stable or transient transfection, respectively. In COS-1 and CHO cells, both the alpha 1D- and alpha 1B-AR were found to couple to PI hydrolysis through a pertussis toxin-insensitive G protein. Both alpha 1-AR subtypes also increased intracellular cAMP by an indirect mechanism, although this effect was observed only in COS-1 cells and not in CHO cells. Interestingly, alpha 1-AR-stimulated arachidonic acid release was also demonstrated for both subtypes in COS-1 cells. This release was mediated through phospholipase A2 activation and involved a pertussis toxin-sensitive G protein. alpha 1-AR-stimulated arachidonic acid release was dependent upon extracellular calcium and was inhibited by 1 microM nifedipine. Inhibitors of protein kinase C, phospholipase C, and diacylglycerol lipase did not alter alpha 1-AR-stimulated release of arachidonic acid. These findings indicate that in COS-1 cells alpha 1-AR-stimulated arachidonic acid release is most likely coupled to dihydropyridine-sensitive L-type calcium channels via a pertussis toxin-sensitive G protein. The influx of extracellular calcium then stimulates phospholipase A2 to release arachidonic acid. alpha 1-AR-stimulated arachidonic acid release could also be demonstrated in CHO cells and was pertussis toxin sensitive but nifedipine insensitive. These cells were also unresponsive to Bay K8644, indicating a lack of voltage-sensitive calcium channels in CHO cells. Nevertheless, alpha 1-AR activation increased intracellular Ca2+ levels, as assessed by fura-2 fluorescence studies. Neomycin blocked both alpha 1-AR-stimulated PI hydrolysis and increases in intracellular Ca2+ levels but did not inhibit the increase in arachidonic acid release. Taken together, these data indicate that in CHO cells alpha 1-ARs can couple directly to phospholipase A2 activation via a pertussis toxin-sensitive pathway. Thus, in these model systems we demonstrate for the first time that a single alpha 1-AR subtype can activate multiple distinct signal transduction pathways, in which Receptor-effector coupling is modulated by distinct G proteins.
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solution phase library screening for the identification of rare clones isolation of an alpha 1d Adrenergic Receptor cdna
Molecular Pharmacology, 1991Co-Authors: Dianne M Perez, Michael T Piascik, Robert M. GrahamAbstract:alpha 1-Adrenergic Receptor (alpha 1-AR) subtypes (alpha 1A and alpha 1B) play a critical role in vascular smooth muscle contraction and circulatory homeostasis. Transcripts for these guanine nucleotide-binding protein-coupled Receptors are extremely low in abundance, however, and isolation of their cDNAs is difficult. We have developed a novel technique for identifying rare clones in a cDNA library, which has been used successfully to isolate a cDNA clone encoding an alpha 1D-AR. A 564-bp polymerase chain reaction product encoding a region between the third and sixth transmembrane domains of the alpha 1D-AR was first generated using rat brain mRNA as template and highly degenerate primers. The primers corresponded to those domains but contained mismatches to the alpha 1B-AR sequences. A 3-kb transcript was identified with this polymerase chain reaction probe, by Northern analysis of rat hippocampus. However, traditional plaque hybridization failed to identify a cDNA in a rat hippocampus lambda gt10 library. By solution-phase screening of virtually the entire library, a cDNA containing a 3-kb insert was identified, amplified, and purified. This insert encodes a 560-amino acid protein corresponding to the topology of guanine nucleotide-binding protein-coupled Receptors. This Receptor has approximately 71% amino acid identity, in the transmembrane regions, to the hamster and rat alpha 1B-ARs. Characterization of the Receptor expressed in COS-7 cells, by ligand binding and photoaffinity labeling, revealed some of the characteristics of an alpha 1A-AR. However, unlike alpha 1A-ARs characterized previously in membrane preparations or in solubilized partially purified preparations, the expressed Receptor could be extensively inactivated by chlorethylclonidine. In addition, it displays ligand-binding properties that are not consistent with an alpha 1A-AR. This indicates that the cDNA clone that we have isolated encodes a novel alpha 1-AR subtype, which we classify as the alpha 1D-AR.
Rb Moreland - One of the best experts on this subject based on the ideXlab platform.
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Cyclic AMP regulates mRNA expression of Alpha-1D and alpha-2a Adrenergic Receptors in cultured human corpus cavernosum smooth muscle cells
International Journal of Impotence Research, 2000Co-Authors: A Traish, Y-h Huang, I Goldstein, Rb MorelandAbstract:While the physiological effects of contractile (e.g. norepinephrine) and relaxatory (e.g. PGE1, forskolin) agents on corpus cavernosum smooth muscle tone have been characterized, the regulation of alpha Adrenergic Receptor mRNA expression in erectile tissue remains to be investigated. The goal of this study was to investigate the modulation of alpha-1 and alpha-2 Adrenergic Receptor mRNA expression in cultured human corpus cavernosum smooth muscle cells in response to increased intracellular cAMP induced by prostaglandin E1 and forskolin. Human corpus cavernosum smooth muscle cells were incubated for 24 h with or without PGE1 (5.7 μM), forskolin (10 μM) or an admixture of both. Total RNA was prepared from the cultures. Expression of Alpha-1D Adrenergic Receptor, alpha-2a Adrenergic Receptor and m2 muscarinic acetylcholine Receptor was determined by RNase protection assays. Loading was normalized by RNase protection of the housekeeping gene, cyclophilin A. The relative abundance of mRNAs was quantitated by scanning densitometry. Treatment of human corpus cavernosum smooth muscle cells with PGE1 or forskolin resulted in decreased mRNA expression of Alpha-1D and alpha-2a Adrenergic Receptors and m2 muscarinic acetylcholine Receptor when compared to untreated cells. Combinations of PGE1 and forskolin produced a more pronounced decrease in mRNA than either agent alone. PGE1 and forskolin increased intracellular levels of cAMP in human corpus cavernosum smooth muscle cells and combinations of both agents produced a more pronounced increase in cAMP synthesis. These results suggest that cAMP modulates the expression of alpha Adrenergic Receptors, one of the principal contractile Receptor systems in the corpora cavernosa. These observations further support the concept that erectile function is a balance between contractile and relaxatory processes, which in turn regulate structure and function of the corpora cavernosa.
Moreland - One of the best experts on this subject based on the ideXlab platform.
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Cyclic AMP regulates mRNA expression of Alpha-1D and alpha-2a Adrenergic Receptors in cultured human corpus cavernosum smooth muscle cells.
International journal of impotence research, 2000Co-Authors: Traish, Huang, Goldstein, MorelandAbstract:While the physiological effects of contractile (e.g. norepinephrine) and relaxatory (e.g. PGE1, forskolin) agents on corpus cavernosum smooth muscle tone have been characterized, the regulation of alpha Adrenergic Receptor mRNA expression in erectile tissue remains to be investigated. The goal of this study was to investigate the modulation of alpha-1 and alpha-2 Adrenergic Receptor mRNA expression in cultured human corpus cavernosum smooth muscle cells in response to increased intracellular cAMP induced by prostaglandin E1 and forskolin. Human corpus cavernosum smooth muscle cells were incubated for 24 h with or without PGE1 (5.7 µM), forskolin (10 µM) or an admixture of both. Total RNA was prepared from the cultures. Expression of Alpha-1D Adrenergic Receptor, alpha-2a Adrenergic Receptor and m2 muscarinic acetylcholine Receptor was determined by RNase protection assays. Loading was normalized by RNase protection of the housekeeping gene, cyclophilin A. The relative abundance of mRNAs was quantitated by scanning densitometry. Treatment of human corpus cavernosum smooth muscle cells with PGE1 or forskolin resulted in decreased mRNA expression of Alpha-1D and alpha-2a Adrenergic Receptors and m2 muscarinic acetylcholine Receptor when compared to untreated cells. Combinations of PGE1 and forskolin produced a more pronounced decrease in mRNA than either agent alone. PGE1 and forskolin increased intracellular levels of cAMP in human corpus cavernosum smooth muscle cells and combinations of both agents produced a more pronounced increase in cAMP synthesis. These results suggest that cAMP modulates the expression of alpha Adrenergic Receptors, one of the principal contractile Receptor systems in the corpora cavernosa. These observations further support the concept that erectile function is a balance between contractile and relaxatory processes, which in turn regulate structure and function of the corpora cavernosa. International Journal of Impotence Research (2000) 12, Suppl 1, S41-S47
Ana Riesgo - One of the best experts on this subject based on the ideXlab platform.
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Delegating Sex: Differential Gene Expression in Stolonizing Syllids Uncovers the Hormonal Control of Reproduction.
Genome Biology and Evolution, 2019Co-Authors: Patricia Álvarez-campos, Nathan J. Kenny, Aida Verdes, Rosa Fernández, Marta Novo, Gonzalo Giribet, Ana RiesgoAbstract:Stolonizationinsyllidannelids is auniquemodeof reproductionamonganimals.Duringthebreedingseason, a structure resemblingthe adult but containing only gametes, called stolon, is formed generally at the posterior end of the animal.When stolons mature, they detachfromthe adult andgametes are released intothewater column. Theprocess is synchronizedwithineachspecies, and it hasbeen reportedtobeunder environmental andendogenous control,probably via endocrine regulation. Tofurtherunderstandreproduction in syllids and to elucidate the molecular toolkit underlying stolonization, we generated Illumina RNA-seq data from different tissues of reproductive and nonreproductive individuals of Syllismagdalena and characterized gene expression during the stolonization process. Several genes involved in gametogenesis (ovochymase, vitellogenin, testis-specific serine/threonine-kinase), immune response (complement Receptor 2), neuronal development (tyrosine-protein kinase Src42A), cell proliferation (Alpha-1D Adrenergic Receptor), and steroid metabolism (hydroxysteroid dehydrogenase 2) were found differentially expressed in the different tissues and conditions analyzed. Inaddition,our findings suggest that severalneurohormones, suchasmethyl farnesoate,dopamine, andserotonin,might trigger stolon formation, the correct maturation of gametes and the detachment of stolonswhen gametogenesis ends. The process seems tobe under circadian control, as indicated by the expression patterns of r-opsins. Overall, our results shed light into the genes that orchestrate the onset of gamete formation and improve our understanding of howsome hormones, previously reported to be involved in reproduction and metamorphosis processes in other invertebrates, seem to also regulate reproduction via stolonization.
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Delegating sex: differential gene expression in stolonizing syllids uncovers the hormonal control of reproduction in Annelida
bioRxiv, 2018Co-Authors: Patricia Álvarez-campos, Nathan J. Kenny, Aida Verdes, Rosa Fernández, Marta Novo, Gonzalo Giribet, Ana RiesgoAbstract:Stolonization in syllid annelids is a unique mode of reproduction among animals. During the breeding season, a structure resembling the adult but containing only gametes, called stolon, is formed at the posterior end of the animal. When the stolons mature, they detach from the adult and the gametes are released into the water column. The process is synchronized within each species, and it has been reported to be under environmental and endogenous control, probably via endocrine regulation. To further understand the reproduction in syllids and to elucidate the molecular toolkit underlying stolonization, we generated Illumina RNA-seq data from different tissues of reproductive and non-reproductive individuals of Syllis magdalena, and characterized gene expression during the stolonization process. Several genes involved in gametogenesis (ovochymase, vitellogenin, testis-specific serine/threonine-kinase), immune response (complement Receptor 2), neuronal development (tyrosine-protein kinase Src42A), cell proliferation (Alpha-1D Adrenergic Receptor), and steroid metabolism (hydroxysteroid dehydrogenase 2) were found differentially expressed in the different tissues and conditions analyzed. In addition, our findings suggest that several neurohormones, such as methyl farnesoate, dopamine and serotonin, might trigger the stolon formation, the correct maturation of gametes and the detachment of stolons when gametogenesis is complete. The process seems to be under circadian control, as indicated by the expression patterns of r-opsins. Overall, our results shed light into the genes that orchestrate the onset of gamete formation, and improve our understanding of how some hormones, previously reported to be involved in reproduction and metamorphosis processes in other invertebrates, seem to also regulate reproduction via stolonization.
A Traish - One of the best experts on this subject based on the ideXlab platform.
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Cyclic AMP regulates mRNA expression of Alpha-1D and alpha-2a Adrenergic Receptors in cultured human corpus cavernosum smooth muscle cells
International Journal of Impotence Research, 2000Co-Authors: A Traish, Y-h Huang, I Goldstein, Rb MorelandAbstract:While the physiological effects of contractile (e.g. norepinephrine) and relaxatory (e.g. PGE1, forskolin) agents on corpus cavernosum smooth muscle tone have been characterized, the regulation of alpha Adrenergic Receptor mRNA expression in erectile tissue remains to be investigated. The goal of this study was to investigate the modulation of alpha-1 and alpha-2 Adrenergic Receptor mRNA expression in cultured human corpus cavernosum smooth muscle cells in response to increased intracellular cAMP induced by prostaglandin E1 and forskolin. Human corpus cavernosum smooth muscle cells were incubated for 24 h with or without PGE1 (5.7 μM), forskolin (10 μM) or an admixture of both. Total RNA was prepared from the cultures. Expression of Alpha-1D Adrenergic Receptor, alpha-2a Adrenergic Receptor and m2 muscarinic acetylcholine Receptor was determined by RNase protection assays. Loading was normalized by RNase protection of the housekeeping gene, cyclophilin A. The relative abundance of mRNAs was quantitated by scanning densitometry. Treatment of human corpus cavernosum smooth muscle cells with PGE1 or forskolin resulted in decreased mRNA expression of Alpha-1D and alpha-2a Adrenergic Receptors and m2 muscarinic acetylcholine Receptor when compared to untreated cells. Combinations of PGE1 and forskolin produced a more pronounced decrease in mRNA than either agent alone. PGE1 and forskolin increased intracellular levels of cAMP in human corpus cavernosum smooth muscle cells and combinations of both agents produced a more pronounced increase in cAMP synthesis. These results suggest that cAMP modulates the expression of alpha Adrenergic Receptors, one of the principal contractile Receptor systems in the corpora cavernosa. These observations further support the concept that erectile function is a balance between contractile and relaxatory processes, which in turn regulate structure and function of the corpora cavernosa.
