scholarly journals Locomotor performance and CNS responses to hypoxia in a cyclic nucleotide-gated channel mutant of adult Drosophila

2021 ◽  
Author(s):  
Shuang Qiu ◽  
Chengfeng Xiao ◽  
R Meldrum Robertson
Keyword(s):  
Cyclic Nucleotide ◽  
Path Length ◽  
Genetic Manipulation ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Hypoxia Response ◽  
Concentration Peak ◽  
Cgmp Signaling ◽  
Gated Channel ◽  
Acute Increase

AbstractDrosophila provides an excellent opportunity to explore the genetic basis for behavioral and CNS responses to hypoxia. Cyclic guanosine monophosphate (cGMP) modulates the speed of recovery from anoxia in adults and mediates hypoxia-related behaviors in larvae. Cyclic nucleotide-gated channels (CNG) and cGMP-activated protein kinase (PKG) are two cGMP downstream targets. PKG is involved in behavioral tolerance to hypoxia and anoxia in adults, however little is known about CNG channels. We used a CNGL mutant with reduced CNGL transcripts to investigate the contribution of CNGL to the hypoxia response. In control flies (w1118), hypoxia immediately reduced path length per minute in a locomotor assay. Flies took 30-40 mins in air to recover from 15 mins hypoxia. CNGL mutants had reduced locomotion under normoxia and impaired recovery from hypoxia, similar to the effects of pan-neural CNGL knockdown. In the CNGL mutants hypoxia caused an acute increase in path length per minute followed by a gradual increase during hypoxia. Basal levels of CNS extracellular K+ concentrations were reduced in the mutants. In response to hypoxia, the mutants had an increased extracellular K+ concentration change, reduced time to reach the K+ concentration peak, and delayed recovery time. Genetic manipulation to increase cGMP in the CNGL mutants eliminated the impairment of recovery from hypoxia and partially compensated for the effects of hypoxia on CNS K+. Although the neural mechanisms have yet to be determined, CNGL channels and cGMP signaling are involved in the hypoxia response of adult Drosophila.

The nitric oxide–cGMP signaling pathway plays a significant role in tolerance to the analgesic effect of morphine

2011 ◽  
Vol 89 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Ercan Ozdemir ◽  
Ihsan Bagcivan ◽  
Nedim Durmus ◽  
Ahmet Altun ◽  
Sinan Gursoy
Keyword(s):  
Nitric Oxide ◽  
Analgesic Effect ◽  
Soluble Guanylate Cyclase ◽  
Morphine Tolerance ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Albino Rats ◽  
Tail Flick ◽  
Analgesic Effects ◽  
Cgmp Signaling

Although the phenomenon of opioid tolerance has been widely investigated, neither opioid nor nonopioid mechanisms are completely understood. The aim of the present study was to investigate the role of the nitric oxide (NO)–cyclic guanosine monophosphate (cGMP) pathway in the development of morphine-induced analgesia tolerance. The study was carried out on male Wistar albino rats (weighing 180–210 g; n = 126). To develop morphine tolerance, animals were given morphine (50 mg/kg; s.c.) once daily for 3 days. After the last dose of morphine was injected on day 4, morphine tolerance was evaluated. The analgesic effects of 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole (YC-1), BAY 41-2272, S-nitroso-N-acetylpenicillamine (SNAP), NG-nitro-l-arginine methyl ester (L-NAME), and morphine were considered at 15 or 30 min intervals (0, 15, 30, 60, 90, and 120 min) by tail-flick and hot-plate analgesia tests (n = 6 in each study group). The results showed that YC-1 and BAY 41-2272, a NO-independent activator of soluble guanylate cyclase (sGC), significantly increased the development and expression of morphine tolerance, and L-NAME, a NO synthase (NOS) inhibitor, significantly decreased the development of morphine tolerance. In conclusion, these data demonstrate that the nitric oxide–cGMP signal pathway plays a pivotal role in developing tolerance to the analgesic effect of morphine.

Impact of hyperleptinemia during placental ischemia-induced hypertension in pregnant rats

2021 ◽  
Author(s):  
Ana C. Palei ◽  
Hunter L. Martin ◽  
Barbara A. Wilson ◽  
Christopher D. Anderson ◽  
Joey P. Granger ◽  
...  
Keyword(s):  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Sprague Dawley ◽  
Pregnant Rats ◽  
No Donor ◽  
Induced Hypertension ◽  
Cgmp Signaling ◽  
Uterine Perfusion ◽  
Plasma Leptin ◽  
Placental Ischemia

The prevalence of preeclampsia and obesity have increased. While obesity is a major risk factor for preeclampsia, the mechanisms linking these morbidities are poorly understood. Circulating leptin levels increase in proportion to fat mass. Infusion of this adipokine elicits hypertension in non-pregnant rats, but less is known about how hyperleptinemia impacts blood pressure during placental ischemia, an initiating event in the pathophysiology of hypertension in preeclampsia. We tested the hypothesis that hyperleptinemia during reduced uterine perfusion pressure (RUPP) exaggerates placental ischemia-induced hypertension. On gestational day (GD) 14, Sprague-Dawley rats were implanted with osmotic mini-pumps delivering recombinant rat leptin (1 mg/kg per min, i.v.) or vehicle concurrently with the RUPP procedure to induce placental ischemia or Sham. On GD 19, plasma leptin was elevated in Sham+Leptin and RUPP+Leptin. Leptin infusion did not significantly impact mean arterial pressure (MAP) in Sham. MAP was increased in RUPP+Vehicle vs. Sham+Vehicle. In contrast to our hypothesis, placental ischemia-induced hypertension was attenuated by leptin infusion. To examine potential mechanisms for attenuation of RUPP-induced hypertension during hyperleptinemia, endothelial-dependent vasorelaxation to acetylcholine was similar between Sham and RUPP; however, endothelial-independent vasorelaxation to the nitric oxide (NO)-donor, sodium nitroprusside, was increased in Sham and RUPP. These findings suggest that NO/cyclic guanosine monophosphate (cGMP) signaling was increased in the presence of hyperleptinemia. Plasma cGMP was elevated in Sham and RUPP hyperleptinemic groups compared to vehicle groups but plasma and vascular NO metabolites were reduced. These data suggest that hyperleptinemia during placental ischemia attenuates hypertension by compensatory increases in NO/cGMP signaling.

The cGMP system: components and function

2020 ◽  
Vol 401 (4) ◽  
pp. 447-469 ◽  
Author(s):  
Franz Hofmann
Keyword(s):  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Signaling System ◽  
Pde Inhibitors ◽  
Mammalian Tissues ◽  
System Components ◽  
Cgmp Signaling ◽  
Dependent Protein ◽  
Successful Approach ◽  
And Function

AbstractThe cyclic guanosine monophosphate (cGMP) signaling system is one of the most prominent regulators of a variety of physiological and pathophysiological processes in many mammalian and non-mammalian tissues. Targeting this pathway by increasing cGMP levels has been a very successful approach in pharmacology as shown for nitrates, phosphodiesterase (PDE) inhibitors and stimulators of nitric oxide-guanylyl cyclase (NO-GC) and particulate GC (pGC). This is an introductory review to the cGMP signaling system intended to introduce those readers to this system, who do not work in this area. This article does not intend an in-depth review of this system. Signal transduction by cGMP is controlled by the generating enzymes GCs, the degrading enzymes PDEs and the cGMP-regulated enzymes cyclic nucleotide-gated ion channels, cGMP-dependent protein kinases and cGMP-regulated PDEs. Part A gives a very concise introduction to the components. Part B gives a very concise introduction to the functions modulated by cGMP. The article cites many recent reviews for those who want a deeper insight.

scholarly journals Two structural components in CNGA3 support regulation of cone CNG channels by phosphoinositides

2013 ◽  
Vol 141 (4) ◽  
pp. 413-430 ◽  
Author(s):  
Gucan Dai ◽  
Changhong Peng ◽  
Chunming Liu ◽  
Michael D. Varnum
Keyword(s):  
Cyclic Nucleotide ◽  
Fold Increase ◽  
Cyclic Guanosine Monophosphate ◽  
Terminal Region ◽  
Guanosine Monophosphate ◽  
Structural Elements ◽  
Apparent Affinity ◽  
Regulatory Modules ◽  
Retinal Photoreceptors ◽  
Dependent Change

Cyclic nucleotide-gated (CNG) channels in retinal photoreceptors play a crucial role in vertebrate phototransduction. The ligand sensitivity of photoreceptor CNG channels is adjusted during adaptation and in response to paracrine signals, but the mechanisms involved in channel regulation are only partly understood. Heteromeric cone CNGA3 (A3) + CNGB3 (B3) channels are inhibited by membrane phosphoinositides (PIPn), including phosphatidylinositol 3,4,5-triphosphate (PIP3) and phosphatidylinositol 4,5-bisphosphate (PIP2), demonstrating a decrease in apparent affinity for cyclic guanosine monophosphate (cGMP). Unlike homomeric A1 or A2 channels, A3-only channels paradoxically did not show a decrease in apparent affinity for cGMP after PIPn application. However, PIPn induced an ∼2.5-fold increase in cAMP efficacy for A3 channels. The PIPn-dependent change in cAMP efficacy was abolished by mutations in the C-terminal region (R643Q/R646Q) or by truncation distal to the cyclic nucleotide-binding domain (613X). In addition, A3-613X unmasked a threefold decrease in apparent cGMP affinity with PIPn application to homomeric channels, and this effect was dependent on conserved arginines within the N-terminal region of A3. Together, these results indicate that regulation of A3 subunits by phosphoinositides exhibits two separable components, which depend on structural elements within the N- and C-terminal regions, respectively. Furthermore, both N and C regulatory modules in A3 supported PIPn regulation of heteromeric A3+B3 channels. B3 subunits were not sufficient to confer PIPn sensitivity to heteromeric channels formed with PIPn-insensitive A subunits. Finally, channels formed by mixtures of PIPn-insensitive A3 subunits, having complementary mutations in N- and/or C-terminal regions, restored PIPn regulation, implying that intersubunit N–C interactions help control the phosphoinositide sensitivity of cone CNG channels.

scholarly journals NMDA receptors and L-arginine/nitric oxide/cyclic guanosine monophosphate pathway contribute to the antidepressant-like effect of Yueju pill in mice

2019 ◽  
Vol 39 (9) ◽  
Author(s):  
Wei Wang ◽  
Tong Zhou ◽  
Rong Jia ◽  
Hailou Zhang ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Forced Swim Test ◽  
Specific Inhibitor ◽  
Tail Suspension Test ◽  
Cyclic Guanosine Monophosphate ◽  
Nmda Receptor Antagonist ◽  
No Synthase ◽  
Guanosine Monophosphate ◽  
Immobility Time ◽  
Cgmp Signaling

Abstract The present study aims to evaluate the involvement of N-methyl-d-aspartate receptor and nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) system in antidepressant-like effects of Yueju pill (YJ), a Chinese herbal medicine. The immobility time in tail suspension test (TST) and forced swim test (FST) was used to assess the antidepressant effects. Prior administration of L-arginine (750 mg/kg, intraperitoneal [i.p.]), a NO synthase substrate that enhances NO signaling or sildenafil (5 mg/kg, i.p.), a phosphodiesterase 5 inhibitor that enhances cGMP, blunted the antidepressant-like activity of YJ (2.7 g/kg, i.g.). Co-treatment of ineffective dose of YJ (1.35 g/kg, i.g.) with one of the reagents that suppress the NO/cGMP signaling, including methylene blue (10 mg/kg, i.p.), an inhibitor of NO synthase; 7-NI (7-nitroinidazole, 30 mg/kg, i.p.), an nNOS specific inhibitor; L-NAME (10 mg/kg, i.p.), a non-specific inhibitor of NO synthase; and MK-801 (0.05 mg/kg, i.p.), an NMDA receptor antagonist, reduced the immobility time in TST and FST, compared with those in vehicle or single drug treatment groups. Neither above drugs alone or co-administrated with YJ affected locomotor activity or anxiety behavior in open field test. Thus, our results suggest that the antidepressant-like action of YJ may depend on the inhibition of NMDA/NO/cGMP pathway.

scholarly journals New Approaches in Oncology for Repositioning Drugs: The Case of PDE5 Inhibitor Sildenafil

2021 ◽  
Vol 11 ◽  
Author(s):  
Marian Cruz-Burgos ◽  
Alberto Losada-Garcia ◽  
Carlos D. Cruz-Hernández ◽  
Sergio A. Cortés-Ramírez ◽  
Ignacio Camacho-Arroyo ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Pde5 Inhibitor ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Systemic Hypertension ◽  
Pde5 Inhibitors ◽  
Development Costs ◽  
Cgmp Signaling ◽  
Molecular Effects ◽  
Approved Drugs

The use of already-approved drugs to treat new or alternative diseases has proved to be beneficial in medicine, because it reduces both drug development costs and timelines. Most drugs can be used to treat different illnesses, due their mechanisms of action are not restricted to one molecular target, organ or illness. Diverging from its original intent offers an opportunity to repurpose previously approved drugs to treat other ailments. This is the case of sildenafil (Viagra), a phosphodiesterase-5 (PDE5) inhibitor, which was originally designed to treat systemic hypertension and angina but is currently commercialized as erectile dysfunction treatment. Sildenafil, tadalafil, and vardenafil are PDE5 inhibitors and potent vasodilators, that extend the physiological effects of nitric oxide and cyclic guanosine monophosphate (cGMP) signaling. Although most of the biological implications of these signaling regulations remain unknown, they offer a large therapeutic potential for several diseases. In addition, some PDE5 inhibitors’ molecular effects seem to play a key role in different illnesses such as kidney disease, diabetes mellitus, and cancer. In this review, we discuss the molecular effects of PDE5 inhibitors and their therapeutic repurposing in different types of cancer.

scholarly journals A Cell-Based PDE4 Assay in 1536-Well Plate Format for High-Throughput Screening

2008 ◽  
Vol 13 (7) ◽  
pp. 609-618 ◽  
Author(s):  
Steven A. Titus ◽  
Xiao Li ◽  
Noel Southall ◽  
Jianming Lu ◽  
James Inglese ◽  
...  
Keyword(s):  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
High Throughput Screening ◽  
Drug Targets ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Compound Screening ◽  
A Cell

The cyclic nucleotide phosphodiesterases (PDEs) are intracellular enzymes that catalyze the hydrolysis of 3,′5′-cyclic nucleotides, such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), to their corresponding 5′nucleotide monophosphates. These enzymes play an important role in controlling cellular concentrations of cyclic nucleotides and thus regulate a variety of cellular signaling events. PDEs are emerging as drug targets for several diseases, including asthma, cardiovascular disease, attention-deficit hyperactivity disorder, Parkinson's disease, and Alzheimer's disease. Although biochemical assays with purified recombinant PDE enzymes and cAMP or cGMP substrate are commonly used for compound screening, cell-based assays would provide a better assessment of compound activity in a more physiological context. The authors report the development and validation of a new cell-based PDE4 assay using a constitutively active G-protein—coupled receptor as a driving force for cAMP production and a cyclic nucleotide—gated cation channel as a biosensor in 1536-well plates. ( Journal of Biomolecular Screening 2008:609-618)

scholarly journals Nitric Oxide-cGMP Signaling in Hypertension

Hypertension ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 1055-1068
Author(s):  
Ehsan Ataei Ataabadi ◽  
Keivan Golshiri ◽  
Annika Jüttner ◽  
Guido Krenning ◽  
A.H. Jan Danser ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Drug Targets ◽  
Soluble Guanylyl Cyclase ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Protein Kinase G ◽  
Current Status ◽  
Systemic Hypertension ◽  
Pharmacological Intervention ◽  
Cgmp Signaling

For the treatment of systemic hypertension, pharmacological intervention in nitric oxide-cyclic guanosine monophosphate signaling is a well-explored but unexploited option. In this review, we present the identified drug targets, including oxidases, mitochondria, soluble guanylyl cyclase, phosphodiesterase 1 and 5, and protein kinase G, important compounds that modulate them, and the current status of (pre)clinical development. The mode of action of these compounds is discussed, and based upon this, the clinical opportunities. We conclude that drugs that directly target the enzymes of the nitric oxide-cyclic guanosine monophosphate cascade are currently the most promising compounds, but that none of these compounds is under investigation as a treatment option for systemic hypertension.

scholarly journals Rap1GAP2 is a new GTPase-activating protein of Rap1 expressed in human platelets

Blood ◽  
2005 ◽  
Vol 105 (8) ◽  
pp. 3185-3192 ◽  
Author(s):  
Jan Schultess ◽  
Oliver Danielewski ◽  
Albert P. Smolenski
Keyword(s):  
Platelet Aggregation ◽  
Splice Variants ◽  
Cyclic Guanosine Monophosphate ◽  
Human Platelets ◽  
Guanosine Monophosphate ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Gtpase Activating Protein ◽  
Guanine Nucleotide Binding Protein ◽  
Cgmp Signaling

AbstractThe Ras-like guanine-nucleotide–binding protein Rap1 controls integrin αIIbβ3 activity and platelet aggregation. Recently, we have found that Rap1 activation can be blocked by the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling pathway by type 1 cGMP-dependent protein kinase (cGKI). In search of possible targets of NO/cGMP/cGKI, we studied the expression of Rap1-specific GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs) in platelets. We could detect mRNAs for a new protein most closely related to Rap1GAP and for postsynaptic density-95 discs-large and zona occludens protein 1 (PDZ)–GEF1 and CalDAG-GEFs I and III. Using 5′–rapid amplification of cDNA ends (RACE), we isolated the complete cDNA of the new GAP encoding a 715-amino acid protein, which we have termed Rap1GAP2. Rap1GAP2 is expressed in at least 3 splice variants, 2 of which are detectable in platelets. Endogenous Rap1GAP2 protein partially colocalizes with Rap1 in human platelets. In transfected cells, we show that Rap1GAP2 exhibits strong GTPase-stimulating activity toward Rap1. Rap1GAP2 is highly phosphorylated, and we have identified cGKI as a Rap1GAP2 kinase. cGKI phosphorylates Rap1GAP2 exclusively on serine 7, a residue present only in the platelet splice variants of Rap1GAP2. Phosphorylation of Rap1GAP2 by cGKI might mediate inhibitory effects of NO/cGMP on Rap1. Rap1GAP2 is the first GTPase-activating protein of Rap1 found in platelets and is likely to have an important regulatory role in platelet aggregation.

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