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Photoreceptors in metazoans can be grouped into two classes, with their photoreceptive membrane derived either from cilia or microvilli. Both classes use some form of the visual pigment protein opsin, which together with 11-cis retinaldehyde absorbs light and activates a G-protein cascade, resulting in the opening or closing of ion channels. Considerable attention has recently been given to the molecular evolution of the opsins and other photoreceptor proteins; much is also known about transduction in the various photoreceptor types.

The capture and utilization of light is an exquisitely evolved process. The single-component microbial opsins, although more limited than multicomponent cascades in processing, display unparalleled compactness and speed. Recent advances in understanding microbial opsins have been driven by molecular engineering for optogenetics and by comparative genomics. Here we provide a Primer on these light-activated ion channels and pumps, describe a group of opsins bridging prior categories, and explore the convergence of molecular engineering and genomic discovery for the utilization and understanding of these remarkable molecular machines.

Pfizer CEO Albert Bourla told Fox News the company has a system in place to turn around a variant-specific jab within 95 days in the likelihood a vaccine-resistant COVID strain emerges, but experts warn that strategy will backfire.

Obesity, a condition affecting more than one in three American adults, is associated with hypothalamic neuronal injury, inflammation, and gliosis- a process cha

Scientific Article | Here we describe two non-invasive methods to chronically control neuronal activity using chemogenetics in mice. Eye-drops were used to...

Designer receptors exclusively activated by designer drugs (DREADDs) modify cellular activity following administration of the exogenous ligand clozapine-N-oxide (CNO). However, some reports indicate CNO may have off-target effects. The current studies investigate the use of Gq DREADDs in CaMKIIa-expressing neurons in the median preoptic nucleus (MnPO). Male Sprague-Dawley rats (250 g) anesthetized with isoflurane were stereotaxically microinjected in the MnPO with the Gq DREADD (AAV5-CaMKIIa-HM3D-mCherry) or control virus (AAV5-CaMKIIa-mCherry). Following a 2-wk recovery, rats were used for either immunohistochemical Fos analysis or in vitro patch-clamp electrophysiology. In Gq DREADD-injected rats, CNO induced significant increases in Fos staining in the MnPO and in regions that receive direct or indirect projections from the MnPO. In electrophysiological studies, CNO depolarized and augmented firing frequency in both Gq DREADD-positive neurons (Gq DREADD) as well as unlabeled MnPO neurons in slices from Gq DREADD-injected rats (Gq DREADDx). Gq DREADDx neurons also displayed increases in spontaneous postsynaptic current (sPSC) frequency in response to CNO. Additionally, CaMKIIa-positive MnPO neurons, which also express nitric oxide synthase (NOS), were treated with Nω-nitro-l-arginine (l-NNA; competitive inhibitor of NOS) and hemoglobin (NO scavenger) to assess the role of NO in Gq DREADDx neuron recruitment. Both l-NNA and hemoglobin blocked CNO-induced effects in Gq DREADDx neurons without affecting Gq DREADD neurons. These findings indicate that Gq DREADD-mediated activation of CaMKIIa/NOS expressing neurons in the MnPO can influence the activity of neighboring neurons. Future studies utilizing the use of Gq DREADDs will need to consider the potential recruitment of additional cell populations. NEW & NOTEWORTHY Rats were injected in the median preoptic nucleus (MnPO) with either an adeno-associated virus (AAV) and excitatory (Gq) designer receptor exclusively activated by designer drugs (DREADD) construct or a control AAV. In the Gq DREADD-injected rats only, clozapine-N-oxide (CNO) increased Fos staining in the MnPO and its targets and increased neuron action potential frequency. In electrophysiology experiments with slices with DREADD cells, unlabeled cells were activated and this was likely due to nitric oxide release by the DREADD cells.

Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) represent a technical revolution in integrative neuroscience. However, the first used ligands exhibited dose-dependent selectivity for their molecular target, leading to potential unspecific effects. Compound 21 (C21) was recently proposed as an alternative, but in vivo characterization of its properties is not sufficient yet. Here, we evaluated its potency to selectively modulate the activity of nigral dopaminergic (DA) neurons through the canonical DREADD receptor hM4Di using TH-Cre rats. In males, 1 mg.kg-1 of C21 strongly increased nigral neurons activity in control animals, indicative of a significant off-target effect. Reducing the dose to 0.5 mg.kg-1 circumvented this unspecific effect, while activated the inhibitory DREADDs and selectively reduced nigral neurons firing. In females, 0.5 mg.kg-1 of C21 induced a transient and residual off-target effect that may mitigated the inhibitory DREADDs-mediated effect. This study raises up the necessity to test selectivity and efficacy of chosen ligands for each new experimental condition.

Abstract. Recently, we created a family of engineered G protein-coupled receptors (GPCRs) called DREADD (designer receptors exclusively activated by designer dr

In the past decade, emerging synthetic biology technologies such as chemogenetics have dramatically transformed how pharmacologists and systems biologists deconstruct the involvement of G protein–coupled receptors (GPCRs) in a myriad of physiological and translational settings. Here we highlight a specific chemogenetic application that extends the utility of the concept of RASSLs (receptors activated solely by synthetic ligands): We have dubbed it DREADDs (designer receptors exclusively activated by designer drugs). As we show in this review, DREADDs are now used ubiquitously to modulate GPCR activity noninvasively in vivo. Results from these studies have directly implicated GPCR signaling in a large number of therapeutically relevant contexts. We also highlight recent applications of DREADD technology that have illuminated GPCR signaling processes that control pathways relevant to the treatment of eating disorders, obesity, and obesity-associated metabolic abnormalities. Additionally, we provide an overview of the potential utility of chemogenetic technologies for transformative therapeutics.

DREADDs (designer receptors exclusively activated by designer drugs) are a powerful and tremendous new technique for selectively manipulating a specific neuronal (or non-neuronal) subpopulation. Recent studies indicate, however, that ligands used for DREADDs, such as clozapine- N -oxide or its parent compound clozapine, are not as selective as expected, even at reasonable concentrations. Although the new generation of ligands specifically developed for DREADDs or alternative chemogenetic receptors may present some improvements, the absence of potential off-target effects remains to be fully demonstrated. Together, indications from the recent literature on DREADDs should warn current and future users about some weaknesses of this expanding technique in the field of integrative neuroscience and encourage them to take some specific precautions to avoid important pitfalls with DREADDs, which remain a promising and complementary approach to optogenetics with the relevant controls. Over the past decade, chemogenetic and optogenetic techniques have revolutionized integrative neuroscience by providing new tools to reversibly manipulate the activity of specific populations or neurotransmitter systems with greater selectivity (Sternson and Roth, 2014; Roth, 2016; Wiegert et al., 2017). Compared with optogenetics, which allow fast and phasic neuronal modulation with high temporal resolution, chemogenetics allow more extended modulation of systems, which is particularly useful for studies focusing on tonic phenomena (e.g., investigation of the implication of dopamine in motivational processes; Whissell et al., 2016). Among chemogenetic tools, designer receptors exclusively activated by designer drugs (DREADDs) are widely used and are referred to as a biological “lock-and-key” system for selective manipulation of cell activity through G-protein signaling pathways. First developed very elegantly by the Roth’s group (Armbruster et al., 2007), this G-protein-coupled receptor (GPCR) is a muscarinic receptor: the lock, which was mutated to respond only to clozapine- N -oxide (CNO), the …

Learn more about DREADD receptors and their ligands and actuators: CNO (clozapine n-oxide), perlapine, DREADD agonist 21 (Compound 21), J60, J52 and SalB (salvinorin B)

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Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) are genetically modified G-protein-coupled receptors (GPCRs), that can be activated by a synthetic ligand which is otherwise inert at endogenous receptors. DREADDs can be expressed in cells in the central nervous system (CNS) and subsequently offer the opportunity for remote and reversible silencing or activation of the target cells when the synthetic ligand is systemically administered. In neuroscience, DREADDs have thus far shown to be useful tools for several areas of research and offer considerable potential for the development of gene therapy strategies for neurological disorders. However, in order to design a DREADD-based gene therapy, it is necessary to first evaluate the viral vector delivery methods utilised in the literature to deliver these chemogenetic tools. This review evaluates each of the prominent strategies currently utilised for DREADD delivery, discussing their respective advantages and limitations. We focus on adeno-associated virus (AAV)-based and lentivirus-based systems, and the manipulation of these through cell-type specific promoters and pseudotyping. Furthermore, we address how virally mediated DREADD delivery could be improved in order to make it a viable gene therapy strategy and thus expand its translational potential.

Hello Bio manufacture higih quality DREADD receptor ligands Clz N Oxide (CNO), Salvinorin B (SalB), J60, J52 and perlapine which activate DREADD receptors in neuroscience research