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Angela B. Lange - One of the best experts on this subject based on the ideXlab platform.
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cloning and functional characterization of octβ2 receptor and tyr1 receptor in the chagas disease vector rhodnius prolixus
Frontiers in Physiology, 2017Co-Authors: Sam Hana, Angela B. LangeAbstract:Octopamine and tyramine, both biogenic amines, are bioactive chemicals important in diverse physiological processes in invertebrates. In insects, Octopamine and tyramine operate analogously to epinephrine and norepinephrine in the vertebrates. Octopamine and tyramine bind to G-protein coupled receptors (GPCRs) leading to changes in second messenger levels and thereby modifying the function in target tissues and insect behaviour. In this paper, we report the cDNA sequences of two GPCRs, RhoprOctβ2-R and RhoprTyr1-R, have been cloned and functionally characterized from Rhodnius prolixus. Octopamine and tyramine each activate RhoprOctβ2-R and RhoprTyr1-R in a dose-dependent manner. Octopamine is one order of magnitude more potent than tyramine in activating RhoprOctβ2-R. Tyramine is two orders of magnitude more potent than Octopamine in activating RhoprTyr1-R. Phentolamine and gramine significantly antagonize RhoprOctβ2-R, whereas yohimbine and phenoxybenzamine are effective blockers of RhoprTyr1-R. The transcripts of both receptors are enriched in the central nervous system (CNS) and are expressed throughout the adult female reproductive system. It has been shown in other insects that Octβ2-R is essential for processes such as ovulation and fertilization. We previously reported that Octopamine and tyramine modulate oviducts and bursa contractions in R. prolixus. Our data confirm the importance of Octopamine and tyramine signaling in the reproductive system of R. prolixus.
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Octopamine and tyramine regulate the activity of reproductive visceral muscles in the adult female blood feeding bug rhodnius prolixus
The Journal of Experimental Biology, 2017Co-Authors: Sam Hana, Angela B. LangeAbstract:ABSTRACT The role of Octopamine and tyramine in regulating spontaneous contractions of reproductive tissues was examined in the female Rhodnius prolixus . Octopamine decreased the amplitude of spontaneous contractions of the oviducts and reduced RhoprFIRFa-induced contractions in a dose-dependent manner, whereas tyramine only reduced the RhoprFIRFa-induced contractions. Both Octopamine and tyramine decreased the frequency of spontaneous bursal contractions and completely abolished the contractions at 5×10 −7 mol l −1 and above. Phentolamine, an Octopamine receptor antagonist, attenuated the inhibition induced by Octopamine on the oviducts and the bursa. Octopamine also increased the levels of cAMP in the oviducts, and this effect was blocked by phentolamine. Dibutyryl cyclic AMP mimicked the effects of Octopamine by reducing the frequency of bursal contractions, suggesting that the Octopamine receptor may act by an Octβ receptor. The tyramine receptor antagonist yohimbine failed to block the inhibition of contractions induced by tyramine on the bursa, suggesting that tyramine may be acting on the Octβ receptor in the bursa.
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Octopamine modulates spermathecal muscle contractions in Locusta migratoria.
Journal of comparative physiology. A Neuroethology sensory neural and behavioral physiology, 2002Co-Authors: J. Clark, Angela B. LangeAbstract:Octopamine was identified in the spermathecal tissue of Locusta migratoria using HPLC and immunohistochemical techniques. Octopamine-like immunoreactive unpaired median neurons were identified in the VIIth and VIIIth (terminal) abdominal ganglia and Octopamine-like immunoreactive axons were present in the ventral ovipositor nerve (branches from this nerve innervate the spermatheca). Stimulatory actions of Octopamine on myogenic and neurogenic contractions were observed. Dose-dependent increases in the frequency of myogenic contractions and the amplitude of neurogenic contractions were elicited by the application of Octopamine to the spermathecal muscle. Non-sustained basal tension increases were noted in some preparations, although these were not found to be dose-dependent. SchistoFLRFamide (PDVDHVFLRFamide) inhibited Octopamine-induced contractions by a maximum of about 30%. In the presence of 3-isobutyl-1-methylxanthine, Octopamine increased cAMP levels in all regions of the spermathecal. The largest increase in cAMP content was found in the spermathecal sac, followed by the straight duct and coil duct. Phentolamine blocked Octopamine-induced increases in cAMP levels and abolished the actions of Octopamine on myogenic contractions.
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Interaction between Octopamine and proctolin on the oviducts of Locusta migratoria.
Journal of insect physiology, 2000Co-Authors: David A. Nykamp, Angela B. LangeAbstract:The biogenic amine Octopamine and the pentapeptide proctolin are two important neuroactive chemicals that control contraction of the oviducts of the African locust Locusta migratoria. The physiological responses and signal transduction pathways used by Octopamine and proctolin have been well characterized in the locust oviducts and this therefore provides the opportunity to examine the interaction between these two pathways. Octopamine, via the intracellular messenger adenosine 3′,5′-cyclic monophosphate (cyclic AMP), inhibits contraction of the oviducts, while proctolin, via the phosphoinositol pathway, stimulates contraction. We have examined the physiological response of the oviducts to combinations of Octopamine and proctolin and also looked at how combinations of these affect one of the main intracellular mediators of the Octopamine response, namely cyclic AMP. It was found that application of Octopamine to the oviducts led to a dose-dependent reduction in tonus of the muscle and also a decrease in the amplitude and frequency of spontaneous phasic contractions. Octopamine-induced relaxation was enhanced in the presence of the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX). Octopamine was also able to inhibit proctolin-induced contractions of the oviducts in a dose-dependent manner. A 10−9 M proctolin-induced contraction was inhibited by 83% in the presence of 10−5 M Octopamine, and was completely inhibited in the presence of 10−5 M Octopamine plus 5×10−4 M IBMX. Octopamine led to a dose-dependent increase in cyclic AMP content as measured by radioimmunoassay. In the presence of 10−9 M proctolin, this Octopamine-induced increase in cyclic AMP was reduced by as much as 60%. Proctolin also caused a dose-dependent decrease in the cyclic AMP elevation produced by 5×10−6 M Octopamine. These results indicate that Octopamine and proctolin can antagonize each other's physiological response when added in combination, and that proctolin is able to modulate the response of the oviducts to Octopamine by influencing cyclic AMP levels.
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Biochemical and physiological effects of Octopamine and selected Octopamine agonists on the oviducts of Locusta migratoria
Journal of Insect Physiology, 1993Co-Authors: Angela B. Lange, Peter K.c. TsangAbstract:Abstract The effects of Octopamine and some selected Octopamine agonists on neurally-evoked contrations and cyclic AMP levels of the lateral oviducts of the locust, Locusta migratoria, have been examined. Octopamine caused reversible, dose-dependent decreases in both the basal tonus and amplitude of neurally-evoked contractions of the lateral oviducts, and inhibited myogenic contractions. The 2-aminooxazoline, Ac6 [2-(4-chloro-o-toluidino)-2-oxazoline], and the substituted phenyliminoimidazolidines (PIIs), NC5 (2,6-diethyl-PII) and NC7 (2-methyl-4-chloro-PII), were each capable of eliciting similar responses to Octopamine on neurally-evoked contractions. The vertebrate α-adrenergic receptor antagonist phentolamine blocked the physiological effects of all agonists tested. The effect of these agonists on cyclic AMP levels was also examined. Octopamine and the three agonists were able to increase the cyclic AMP content of the lateral oviducts in a dose-dependent manner. The increases in cyclic AMP were inhibited in the presence of various vertebrate receptor antagonists. The results of this study indicate that AC6, NC5, and NC7 all act as agonists to the Octopamine2-like receptors present on locust oviduct and confirm previous studies for the agonistic properties of these agents.
Scott Waddell - One of the best experts on this subject based on the ideXlab platform.
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layered reward signalling through Octopamine and dopamine in drosophila
Nature, 2012Co-Authors: Christopher J Burke, Wolf Huetteroth, David Owald, Emmanuel Perisse, Michael J Krashes, Daryl M Gohl, Marion Silies, Sarah J Certel, Scott WaddellAbstract:Dopamine is synonymous with reward in mammals but associated with aversive reinforcement in insects, where reward seems to be signalled by Octopamine; here it is shown that flies have discrete populations of dopamine neurons representing positive or negative values that are coordinately regulated by Octopamine. The neurotransmitter dopamine has been synonymous with reward in mammals, but is associated with aversive reinforcement in insects. In insects, it was thought, reward was signalled by Octopamine. Now Scott Waddell and colleagues show that flies have discrete 'negative' and 'positive' populations of dopamine neurons, which are coordinately regulated by Octopamine. This work reconciles previous findings with Octopamine and dopamine, and suggests that reinforcement systems in flies are more like those in mammals than previously thought. Dopamine is synonymous with reward and motivation in mammals1,2. However, only recently has dopamine been linked to motivated behaviour and rewarding reinforcement in fruitflies3,4. Instead, Octopamine has historically been considered to be the signal for reward in insects5,6,7. Here we show, using temporal control of neural function in Drosophila, that only short-term appetitive memory is reinforced by Octopamine. Moreover, Octopamine-dependent memory formation requires signalling through dopamine neurons. Part of the Octopamine signal requires the α-adrenergic-like OAMB receptor in an identified subset of mushroom-body-targeted dopamine neurons. Octopamine triggers an increase in intracellular calcium in these dopamine neurons, and their direct activation can substitute for sugar to form appetitive memory, even in flies lacking Octopamine. Analysis of the β-adrenergic-like OCTβ2R receptor reveals that Octopamine-dependent reinforcement also requires an interaction with dopamine neurons that control appetitive motivation. These data indicate that sweet taste engages a distributed Octopamine signal that reinforces memory through discrete subsets of mushroom-body-targeted dopamine neurons. In addition, they reconcile previous findings with Octopamine and dopamine and suggest that reinforcement systems in flies are more similar to mammals than previously thought.
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Layered reward signalling through Octopamine and dopamine in Drosophila
Nature, 2012Co-Authors: Christopher J Burke, Wolf Huetteroth, David Owald, Emmanuel Perisse, Michael J Krashes, Daryl M Gohl, Marion Silies, Sarah J Certel, Gaurav Das, Scott WaddellAbstract:Dopamine is synonymous with reward and motivation in mammals. However, only recently has dopamine been linked to motivated behaviour and rewarding reinforcement in fruitflies. Instead, Octopamine has historically been considered to be the signal for reward in insects. Here we show, using temporal control of neural function in Drosophila, that only short-term appetitive memory is reinforced by Octopamine. Moreover, Octopamine-dependent memory formation requires signalling through dopamine neurons. Part of the Octopamine signal requires the α-adrenergic-like OAMB receptor in an identified subset of mushroom-body-targeted dopamine neurons. Octopamine triggers an increase in intracellular calcium in these dopamine neurons, and their direct activation can substitute for sugar to form appetitive memory, even in flies lacking Octopamine. Analysis of the β-adrenergic-like OCTβ2R receptor reveals that Octopamine-dependent reinforcement also requires an interaction with dopamine neurons that control appetitive motivation. These data indicate that sweet taste engages a distributed Octopamine signal that reinforces memory through discrete subsets of mushroom-body-targeted dopamine neurons. In addition, they reconcile previous findings with Octopamine and dopamine and suggest that reinforcement systems in flies are more similar to mammals than previously thought.
Sam Hana - One of the best experts on this subject based on the ideXlab platform.
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cloning and functional characterization of octβ2 receptor and tyr1 receptor in the chagas disease vector rhodnius prolixus
Frontiers in Physiology, 2017Co-Authors: Sam Hana, Angela B. LangeAbstract:Octopamine and tyramine, both biogenic amines, are bioactive chemicals important in diverse physiological processes in invertebrates. In insects, Octopamine and tyramine operate analogously to epinephrine and norepinephrine in the vertebrates. Octopamine and tyramine bind to G-protein coupled receptors (GPCRs) leading to changes in second messenger levels and thereby modifying the function in target tissues and insect behaviour. In this paper, we report the cDNA sequences of two GPCRs, RhoprOctβ2-R and RhoprTyr1-R, have been cloned and functionally characterized from Rhodnius prolixus. Octopamine and tyramine each activate RhoprOctβ2-R and RhoprTyr1-R in a dose-dependent manner. Octopamine is one order of magnitude more potent than tyramine in activating RhoprOctβ2-R. Tyramine is two orders of magnitude more potent than Octopamine in activating RhoprTyr1-R. Phentolamine and gramine significantly antagonize RhoprOctβ2-R, whereas yohimbine and phenoxybenzamine are effective blockers of RhoprTyr1-R. The transcripts of both receptors are enriched in the central nervous system (CNS) and are expressed throughout the adult female reproductive system. It has been shown in other insects that Octβ2-R is essential for processes such as ovulation and fertilization. We previously reported that Octopamine and tyramine modulate oviducts and bursa contractions in R. prolixus. Our data confirm the importance of Octopamine and tyramine signaling in the reproductive system of R. prolixus.
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Octopamine and tyramine regulate the activity of reproductive visceral muscles in the adult female blood feeding bug rhodnius prolixus
The Journal of Experimental Biology, 2017Co-Authors: Sam Hana, Angela B. LangeAbstract:ABSTRACT The role of Octopamine and tyramine in regulating spontaneous contractions of reproductive tissues was examined in the female Rhodnius prolixus . Octopamine decreased the amplitude of spontaneous contractions of the oviducts and reduced RhoprFIRFa-induced contractions in a dose-dependent manner, whereas tyramine only reduced the RhoprFIRFa-induced contractions. Both Octopamine and tyramine decreased the frequency of spontaneous bursal contractions and completely abolished the contractions at 5×10 −7 mol l −1 and above. Phentolamine, an Octopamine receptor antagonist, attenuated the inhibition induced by Octopamine on the oviducts and the bursa. Octopamine also increased the levels of cAMP in the oviducts, and this effect was blocked by phentolamine. Dibutyryl cyclic AMP mimicked the effects of Octopamine by reducing the frequency of bursal contractions, suggesting that the Octopamine receptor may act by an Octβ receptor. The tyramine receptor antagonist yohimbine failed to block the inhibition of contractions induced by tyramine on the bursa, suggesting that tyramine may be acting on the Octβ receptor in the bursa.
Thomas Roeder - One of the best experts on this subject based on the ideXlab platform.
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chapter 25 pharmacology and molecular biology of Octopamine receptors from different insect species
Progress in Brain Research, 1995Co-Authors: Thomas Roeder, Joern Degen, C Dyczkowski, Michael GeweckeAbstract:Publisher Summary This chapter discusses the pharmacology and molecular biology of Octopamine receptors. It studies the structure and pharmacology of Octopamine receptors using two different radioligands. In addition to the natural agonist Octopamine, the phenlyiminoimidazolidine derivative 3 H-NC-SZ served as the second radioligand. Because it has a higher affinity and it is not degraded by endogenous enzymes, it is much better suited for ligand-binding studies. Using these radioligands, the Octopamine receptor of the locusts, Schistocerca gregaria and Locusta migratoria , and the honey bee Apis mellifera are studied in detail in the chapter. In all these preparations, Octopamine receptors are present in relatively high concentrations. In the desert locust—for example, Schistocerca gregaria—the maximal concentration of binding sites is approx. 10-times higher if compared with 5-HT and 20-times higher if compared with dopamine receptors. Only the neuronal histamine H1-like receptor has a slightly higher concentration of binding sites. This indicates the important role of Octopamine in the nervous system of insects. Most pharmacological studies of insect neuronal Octopamine receptors have been performed using locusts. High-affinity antagonists are well suited for physiological studies. The most important among them are the tetracyclic substances, mianserin and, with even higher affinity, the structurally related substance, maroxepine.
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Characterization of insect neuronal Octopamine receptors (OA3 receptors)
Neurochemical research, 1993Co-Authors: Thomas Roeder, James A. NathansonAbstract:Octopamine receptors in the nervous tissue of insects were investigated using a ligand-receptor assay with [3H]NC-5Z or [3H]Octopamine as the radioligands. Both ligands recognized a homogenous class of binding sites with the properties of an Octopamine receptor. This receptor has been characterized pharmacologically. Both high-affinity agonists (e.g. NC 7, K1=0.3 nM) and antagonists (e.g. maroxepine, K1=1.02 nM) were investigated. The neuronal Octopamine receptor belongs to a receptor class that can easily be distinguished from peripheral Octopamine receptors. Initial investigations of the localization of Octopamine receptors within the insect nervous tissue show the greatest receptor density in the optic lobes.
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A new Octopamine receptor class in locust nervous tissue, the Octopamine 3 (OA3) receptor.
Life sciences, 1992Co-Authors: Thomas RoederAbstract:The insect neuronal 3H-Octopamine binding site represents a new type of Octopamine receptor. This receptor has pharmacological features that are characteristic for all known Octopamine receptors, but it is possible to distinguish this receptor class from all others using either agonists or antagonists. The quantitative determination of the pharmacological relationships to the other Octopamine receptor classes could demonstrate greatest homology with both class 2 (OA2A and OA2B) receptors. Therefore, the neuronal Octopamine receptor should be named a class 3 receptor (OA3). A new and simple classification scheme for Octopamine receptors which enables classification of the new receptor class is established using antagonists.
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Octopamine receptors in locust nervous tissue.
Biochemical pharmacology, 1990Co-Authors: Thomas Roeder, Michael GeweckeAbstract:Abstract The Octopamine binding site in the nervous tissue of the migratory locust Locusta migratoria is identified as an Octopamine receptor of class 2. The binding of Octopamine to the binding site is saturable, reversible, stereospecific and shows a pharmacological profile typlcal for Octopamine receptors. Saturation analysis results in a single class of non-interacting binding sites ( K d = 7.9 ± 0.9 nM ; Bmax = 160 fmol/mg). The pharmacological analysis shows that the phenyliminoimidazolidines NC7 and NC5 (Ki= 0.29 and 0.87 nM, respectively) are the most potent agonists, and that mianserin (Ki = 1.20nM) is the most potent antagonist ever reported for Octopamine receptors in direct binding studies.
B. Pophof - One of the best experts on this subject based on the ideXlab platform.
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Octopamine modulates the sensitivity of silkmoth pheromone receptor neurons.
Journal of comparative physiology. A Sensory neural and behavioral physiology, 2000Co-Authors: B. PophofAbstract:Effects of Octopamine and its antagonist epinastine on electrophysiological responses of receptor neurons of Antheraea polyphemus specialised to the pheromone components (E,Z)-6,11-hexadecadienyl acetate and (E,Z)-6,11-hexadecadienal were investigated. Injections of Octopamine and epinastine into the moths had no effect on the transepithelial potential of the antennal-branch preparation nor on the spontaneous nerve impulse frequency in either type of receptor neuron. However, in the presence of continuous low-intensity pheromone stimulation, Octopamine significantly increased the nerve impulse frequency in the acetate receptor neuron, but not in the aldehyde receptor neuron. Octopamine and epinastine had no significant effect on the receptor potential amplitudes elicited in both receptor neuron types by pheromone stimulation. However, the peak nerve impulse frequency in the response of both receptor neuron types to pheromone was significantly affected: decreased by epinastine and increased by Octopamine over a broad range of pheromone concentrations. In control experiments, injection of physiological saline did not significantly alter the peak nerve impulse frequency. The effect of Octopamine was established within 1 h after injection and persisted for about 4 h. The possibility of a direct action of Octopamine on the nerve impulse generation by the receptor neurons is discussed.
