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Yang N, Yang J, Liu Y, Fan H, Ji L, Wu T, Jia D, Ye Q, Wu G. Impaired learning and memory in mice induced by nano neodymium oxide and possible mechanisms. ENVIRONMENTAL TOXICOLOGY 2021; 36:1514-1520. [PMID: 33938091 DOI: 10.1002/tox.23148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 03/19/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
A growing number of individuals are now exposed to neodymium (Nd) owing to its extensive applications. However, the biological effects of Nd on humans, especially on learning and memory, remain elusive. To investigate whether Nd exposure affects learning and memory, in this study female ICR mice were exposed to nano Nd2 O3 via intranasal instillation at doses of 50, 100, and 150 mg/kg body weight, daily for 45 days. According to Morris water maze data, learning and memory parameters were significantly reduced in the 150 mg/kg nano-Nd2 O3 group than the sham control. Furthermore, inductively coupled plasma-mass spectroscopy analysis revealed that Nd levels were significantly higher in the hippo campus of the 100 and 150 mg/kg exposed group than the sham control; however, no significant differences were observed in the hippocampal histopathology between these groups. Furthermore, reactive oxygen species were elevated in hippocampal tissues of experimental groups than the sham control, 447.3 in high dose group and 360.0 in control group; however, malondialdehyde levels were significantly increased and superoxide dismutase activities were decreased only in mice exposed to 100 and 150 mg/kg Nd2 O3 . High-performance liquid chromatography data demonstrated that levels of glutamic acid, glycine, and gamma-aminobutyric acid were higher in the hippocampus of mice exposed to 150 mg/kg Nd2 O3 than the sham control. Our findings indicated that the neuronal injury was induced by disruption of the oxidation-antioxidation homeostasis and altered amino acid neurotransmitter levels in the hippocampus, which could result in the poor cognitive performance demonstrated by exposed mice.
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Affiliation(s)
- Ning Yang
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
- Department of Nephrology, The First Affiliated Hospital of Baotou Medical College, Baotou, China
| | - Jing Yang
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
| | - Yang Liu
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
| | - Hongxing Fan
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
| | - Le Ji
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
| | - Tao Wu
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
- Department of Nephrology, The First Affiliated Hospital of Baotou Medical College, Baotou, China
| | - Dantong Jia
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
| | - Qianru Ye
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
| | - Gang Wu
- Department of Preclinical Medicine and Forensic, Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China
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Singh P, Walia V. Anxiolytic like effect of L-Carnitine in mice: Evidences for the involvement of NO-sGC-cGMP signaling pathway. Behav Brain Res 2020; 391:112689. [PMID: 32417275 DOI: 10.1016/j.bbr.2020.112689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/26/2020] [Accepted: 05/02/2020] [Indexed: 12/20/2022]
Abstract
L-Carnitine (LC) is an endogenous compound synthesized from the essential amino acids lysine and methionine. LC act as an antioxidant and modulates the levels of neurochemicals such as glutamate, GABA, NO etc. implicated in the regulation of anxiety and related behavior. However its exact role in the anxiety is not known. The present study was designed to investigate the anxiolytic like effect of LC in mice. LC (2.5, 5.0 and 10 mg/kg, i.p.) was administered to the mice and the anxiety related behavior was determined using light and dark box (LDB) and elevated plus maze (EPM) tests. The whole brain nitrite level was also determined. The results obtained demonstrated that LC (10 mg/kg, i.p.) exerted anxiolytic like effect in mice, accompanied by the reduction of whole brain nitrite level significantly as compared to control. Further, the influence of NO and GABA modulators pretreatments on the effect of subtherapeutic dose of LC was also determined. The results obtained demonstrated that NO donor/cGMP modulator counteracted while NO inhibitor potentiated the effect confers by the subtherapeutic dose of LC mice. Pretreatment of diazepam (1 mg/kg, i.p.) further potentiated the effect of subtherapeutic dose of LC (5 mg/kg, i.p.) in EPM and LDB tests and further reduced the brain nitrite level significantly as compared to LC (5 mg/kg, i.p.) alone treatment. Thus, LC exerted anxiolytic like effect in mice and NO-sGC-cGMP signaling pathway influences the anxiolytic like effect of LC in mice.
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Affiliation(s)
- Poonam Singh
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, 124001, Haryana, India.
| | - Vaibhav Walia
- Faculty of Pharmacy, DIT University, Dehradun, India.
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Yang X, Tan J, Xu X, Yang H, Wu F, Xu B, Liu W, Shi P, Xu Z, Deng Y. Prepubertal overexposure to manganese induce precocious puberty through GABA A receptor/nitric oxide pathway in immature female rats. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 188:109898. [PMID: 31711775 DOI: 10.1016/j.ecoenv.2019.109898] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 10/13/2019] [Accepted: 10/29/2019] [Indexed: 06/10/2023]
Abstract
Gamma-aminobutyric acid (GABA) plays a critical role in regulation of gonadotropin-releasing hormone (GnRH) through GABAA receptor (GABAAR). Nitric oxide (NO) production has correlation with GABA and regulates GnRH secretion. This study was performed to examine the mechanisms by which manganese (Mn) accelerate puberty onset involves GABAAR/NO pathway in the preoptic area-anterior hypothalamus (POA-AH) in immature female rats. First, female rats received daily dose of MnCl2 0 (saline), 2.5, 5 and 10 mg/kg b.w by oral gavage during postnatal day (PND) 21-32. Animals administered with 10 mg/kg MnCl2 exhibited earlier puberty onset age and advanced ovary and uterus development than these in saline-treatment group. Furthermore, we found that decrease of GABAAR result in elevated production of nitric oxide synthase1 (NOS1), NO and GnRH in the POA-AH. Second, we recorded the neuronal spikes alternation after perfusion with GABAAR inhibitor bicuculline (BIC), GABAAR agonist isoguvacine (isog), and MnCl2 from the POA-AH in acute brain slices of PND21 rats. Spontaneous firing revealed a powerful GABAAR-mediated action on immature POA-AH and confirm that MnCl2 has a significant effect on GABAAR. Third, we revealed that decrease in NOS1 and NO production by treatment with isog-alone or isog+MnCl2 contribute to the decrease of GnRH in the POA-AH and a delayed puberty onset age compared to treatment with MnCl2-alone. Together, these results suggested that excessive exposure to MnCl2 stimulates NO production through decreased GABAAR in the POA-AH to advance puberty onset in immature female rats.
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Affiliation(s)
- Xinxin Yang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, China.
| | - Jichun Tan
- Assisted Reproduction Center, Obstetrics and Gynecology Department, Shengjing Hospital Affiliated to China Medical University, Shenyang, 110004, China.
| | - Xiaoyan Xu
- Assisted Reproduction Center, Obstetrics and Gynecology Department, Shengjing Hospital Affiliated to China Medical University, Shenyang, 110004, China.
| | - Haibo Yang
- Department of Occupational Diseases, Linyi People's Hospital, Shandong, 276000, China.
| | - Fengdi Wu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, China.
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, China.
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, China.
| | - Pengcheng Shi
- Department of Information Center, The Fourth Affiliated Hospital of China Medical, 110000, China.
| | - Zhaofa Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, China.
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110122, China.
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NO-sGC-cGMP signaling influence the anxiolytic like effect of lithium in mice in light and dark box and elevated plus maze. Brain Res 2018; 1704:114-126. [PMID: 30292770 DOI: 10.1016/j.brainres.2018.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 09/17/2018] [Accepted: 10/02/2018] [Indexed: 11/23/2022]
Abstract
Glutamate is an excitatory neurotransmitter implicated in the pathogenesis of psychiatric disorders. Glutamate results in the activation of an enzyme called glycogen synthase kinase-3 (GSK-3) acting through N-methyl-d-aspartate (NMDA) receptors. Impaired expression of GSK-3 affects behavior and neurochemicals level in the brain responsible for the pathogenesis of mood disorders. It has been reported that lithium acts as an inhibitor of GSK-3 and inhibit the enzyme GSK-3 in an uncompetitive manner. In the present study, anxiolytic like effect of lithium in mice is investigated through light and dark box (LDB) and elevated plus maze (EPM). Lithium (50, 100 and 200 mg/kg, i.p.) was administered to the mice to determine the anxiety related behavior. Results obtained suggests that the administration of lithium (100 mg/kg, i.p.) reversed the anxiety related behavior of mice and decreased the levels of glutamate and nitrite as compared to control. Glutamate acting through the NMDA receptor has been found to regulate the expression of enzyme neuronal nitric oxide synthase (nNOS), which is responsible for the release of nitric oxide (NO), suggesting a possible link between NO and GSK-3 also. Therefore, to determine the possible interaction with NO, sub-effective dose of lithium was administered in combination with NO donor i.e. l-Arginine (50 mg/kg, i.p.), NOS and soluble guanylate cyclase (sGC) inhibitor i.e. methylene blue (1 mg/kg, i.p.) and phosphodiesterase inhibitor i.e. sildenafil (1 mg/kg, i.p.). The results obtained demonstrated that the anxiolytic like effect of lithium was abolished by the pretreatment with NO donor and potentiated by the pretreatment with NOS inhibitor. Therefore, it is suggested that NO signaling pathway influence the anxiolytic like activity of lithium in mice, further suggesting the link between the GSK-3 and NO signaling in the regulation of anxiety related behavior.
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Walia V, Garg C, Garg M. Anxiolytic-like effect of pyridoxine in mice by elevated plus maze and light and dark box: Evidence for the involvement of GABAergic and NO-sGC-cGMP pathway. Pharmacol Biochem Behav 2018; 173:96-106. [PMID: 30040985 DOI: 10.1016/j.pbb.2018.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/21/2018] [Accepted: 06/11/2018] [Indexed: 10/28/2022]
Abstract
Present study was carried out to investigate the 'anxiolytic-like' effect of pyridoxine in mice. Pyridoxine (90, 180 and 360 mg/kg) was administered by intraperitoneal (i.p.) route to the experimental mice and anxiety-related behavior was evaluated by light and dark box (LDB) and elevated plus maze (EPM) models. Glutamate, GABA and nitrite levels were also determined in the isolated whole brain of mice. It was observed that pyridoxine (180 mg/kg, i.p.) exerted 'anxiolytic-like' effect in mice in EPM and LDB models. Also, there was a significant increase in the levels of GABA whereas; the levels of glutamate and nitrite were decreased as compared to the control group. Administration of pentamethylene tetrazole (PTZ; 20 mg/kg, i.p.) exerted anxiogenic effects in mice, but the combination of PTZ and pyridoxine (180 mg/kg, i.p.) abolished the 'anxiolytic-like' effect of pyridoxine, thereby, suggesting the possible role of GABA in the 'anxiolytic-like' effect of pyridoxine in mice. Further, the influence of NO-sGC-cGMP pathway was investigated by administering the sub-effective dose of pyridoxine in combination with sub-threshold doses of NO modulators i.e. l‑arginine (50 mg/kg, i.p.; NO donor); methylene blue (1 mg/kg, i.p.; NO and soluble guanylate cyclase inhibitor) and sildenafil (1 mg/kg, i.p.; phosphodiesterase inhibitor and cGMP modulator). It was observed that the 'anxiolytic-like' effect of pyridoxine in mice was counteracted by the NO donor and potentiated by the NO inhibitors. Thus, the present study confirmed the involvement of GABAergic and NO-sGC-cGMP pathway in the 'anxiolytic-like' effect of pyridoxine in mice.
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Affiliation(s)
- Vaibhav Walia
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Chanchal Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Munish Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
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Saeedi Saravi SS, Arefidoust A, Yaftian R, Saeedi Saravi SS, Dehpour AR. 17α-ethinyl estradiol attenuates depressive-like behavior through GABAA receptor activation/nitrergic pathway blockade in ovariectomized mice. Psychopharmacology (Berl) 2016; 233:1467-85. [PMID: 26883875 DOI: 10.1007/s00213-016-4242-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/08/2016] [Indexed: 01/11/2023]
Abstract
OBJECTIVES This study was performed to investigate the antidepressant-like effect of 17α-ethinyl estradiol (EE2) in ovariectomized (OVX) mice and the possible role of nitrergic and gamma aminobutyric acid (GABA)ergic pathways in this paradigm. METHODS Bilateral ovariectomy was performed in female mice, and different doses of EE2 were intraperitoneally injected either alone or combined with GABAA agonist, diazepam, GABAA antagonist, flumazenil, non-specific nitric oxide synthase (NOS) inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), specific nNOS inhibitor, 7-nitroindazole (7-NI), a nitric oxide (NO) precursor, L-arginine, and selective PDE5I, sildenafil. After locomotion assessment, immobility times were recorded in the forced swimming test (FST) and tail suspension test (TST). Moreover, hippocampal nitrite concentrations were measured in the examined groups. RESULTS Ten days after ovariectomy, a significant prolonged immobility times were observed. EE2 (0.3 and 1μg/kg and 0.03, 0.1, and 1mg/kg) caused antidepressant-like activity in OVX mice in FST and TST. Diazepam (1 and 5mg/kg), L-NAME (30mg/kg), and 7-NI (100mg/kg) significantly reduced the immobility times. Co-administration of minimal and sub-effective doses of EE2 and diazepam (0.3μg/kg and 0.5mg/kg, respectively) exerted a significant antidepressant-like effect. The same effect was observed in combination of minimal and sub-effective doses of EE2 and either L-NAME or 7-NI. Moreover, combination of minimal and sub-effective doses of EE2, diazepam either L-NAME, or 7-NI emphasized the significant robust antidepressant-like activity. CONCLUSIONS The study has demonstrated that lowest dose of EE2 exerts a significant antidepressant-like behavior. It is suggested that suppression of NO system, as well as GABAA activation, may be responsible for antidepressant-like activity of EE2 in OVX mice. Moreover, GABAA activation may inhibit nitrergic pathway.
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Affiliation(s)
- Seyed Soheil Saeedi Saravi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, 13145-784, Tehran, Iran.,Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology-Pharmacology, Faculty of Pharmacy, Guilan University of Medical Sciences, Rasht, Iran
| | - Alireza Arefidoust
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, 13145-784, Tehran, Iran.,Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Rahele Yaftian
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, 13145-784, Tehran, Iran.,Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Sobhan Saeedi Saravi
- Department of Toxicology-Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Reza Dehpour
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, 13145-784, Tehran, Iran. .,Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.
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Tanaka S, Sugiyama N, Takahashi Y, Mantoku D, Sawabe Y, Kuwabara H, Nakano T, Shimamoto C, Matsumura H, Marunaka Y, Nakahari T. PPARα autocrine regulation of Ca²⁺-regulated exocytosis in guinea pig antral mucous cells: NO and cGMP accumulation. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1169-79. [PMID: 25342048 DOI: 10.1152/ajpgi.00311.2013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In antral mucous cells, acetylcholine (ACh, 1 μM) activates Ca(2+)-regulated exocytosis, consisting of a peak in exocytotic events that declines rapidly (initial phase) followed by a second slower decline (late phase) lasting during ACh stimulation. GW7647 [a peroxisome proliferation activation receptor α (PPARα) agonist] enhanced the ACh-stimulated initial phase, and GW6471 (a PPARα antagonist) abolished the GW7647-induced enhancement. However, GW6471 produced the delayed, but transient, increase in the ACh-stimulated late phase, and it also decreased the initial phase and produced the delayed increase in the late phase during stimulation with ACh alone. A similar delayed increase in the ACh-stimulated late phase is induced by an inhibitor of the PKG, Rp8BrPETcGMPS, suggesting that GW6471 inhibits cGMP accumulation. An inhibitor of nitric oxide synthase 1 (NOS1), N(5)-[imino(propylamino)methyl]-L-ornithine hydrochloride (N-PLA), also abolished the GW7647-induced-enhancement of ACh-stimulated initial phase but produced the delayed increase in the late phase. However, in the presence of N-PLA, an NO donor or 8BrcGMP enhanced the ACh-stimulated initial phase and abolished the delayed increase in the late phase. Moreover, GW7647 and ACh stimulated NO production and cGMP accumulation in antral mucosae, which was inhibited by GW6471 or N-PLA. Western blotting and immunohistochemistry revealed that NOS1 and PPARα colocalize in antral mucous cells. In conclusion, during ACh stimulation, a PPARα autocrine mechanism, which accumulates NO via NOS1 leading to cGMP accumulation, modulates the Ca(2+)-regulated exocytosis in antral mucous cells.
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Affiliation(s)
- Saori Tanaka
- Nakahari Project of Central Research Laboratory, Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Nanae Sugiyama
- Nakahari Project of Central Research Laboratory, Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Yuko Takahashi
- Nakahari Project of Central Research Laboratory, Mechanobiology Laboratory, Graduate School of Medicine, Nagoya University, Nagoya, Japan, and
| | - Daiki Mantoku
- Nakahari Project of Central Research Laboratory, Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Yukinori Sawabe
- Nakahari Project of Central Research Laboratory, Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hiroko Kuwabara
- Nakahari Project of Central Research Laboratory, Department of Pathology, and
| | - Takashi Nakano
- Nakahari Project of Central Research Laboratory, Department of Microbiology and Infection Control, Osaka Medical College, Takatsuki, Japan
| | - Chikao Shimamoto
- Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Hitoshi Matsumura
- Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Yoshinori Marunaka
- Nakahari Project of Central Research Laboratory, Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takashi Nakahari
- Nakahari Project of Central Research Laboratory, Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Dhingra A, Tummala SR, Lyubarsky A, Vardi N. PDE9A is expressed in the inner retina and contributes to the normal shape of the photopic ERG waveform. Front Mol Neurosci 2014; 7:60. [PMID: 25018695 PMCID: PMC4073215 DOI: 10.3389/fnmol.2014.00060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/09/2014] [Indexed: 11/19/2022] Open
Abstract
The ubiquitous second messenger cGMP is synthesized by guanylyl cyclase and hydrolyzed by phosphodiesterase (PDE). cGMP mediates numerous signaling pathways in multiple tissues. In the retina, cGMP regulates signaling in nearly every cell class including photoreceptors, bipolar cells, amacrine cells, and ganglion cells. In order to understand the specific role of cGMP and its regulating enzymes in different cell types, it is first necessary to localize these components and dissect their influence on the circuits. Here we tested the contribution of PDE9A to retinal processing by recording the electroretinograms (ERG) of PDE9A™/™ (KO) mice and by localizing the enzyme. We found that while the scotopic ERG of KO was the same as that of wild type (WT) in both amplitude and kinetics, the photopic ERG was greatly affected. The greatest effect was on the recovery of the b-wave; the falling phase and the b-wave duration were significantly longer in the KO mice for all photopic stimuli (UV, green, or saturating white flashes). The rising phase was slower in KO than in WT for UV and green stimuli. For certain stimuli, amplitudes of both the a- and b-waves were smaller than in WT. Using Lac-Z expression in KO retinas as a reporter for PDE9A expression pattern, we found that PDE9A is localized to GABA-positive and GABA-negative amacrine cells, and likely also to certain types of ganglion cells. Our results indicate that PDE9A, by controlling the level of cGMP, modulates inhibitory processes within the cone pathway. We speculate that these circuits involve NO/cGMP signaling pathways.
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Affiliation(s)
- Anuradha Dhingra
- Retina Lab, Department of Neuroscience, University of Pennsylvania Philadelphia, PA, USA
| | - Shanti R Tummala
- Retina Lab, Department of Neuroscience, University of Pennsylvania Philadelphia, PA, USA
| | - Arkady Lyubarsky
- Department of Ophthalmology, University of Pennsylvania Philadelphia, PA, USA
| | - Noga Vardi
- Retina Lab, Department of Neuroscience, University of Pennsylvania Philadelphia, PA, USA
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Tanaka S, Tanaka R, Harada S, Kohda Y, Matsumura H, Shimamoto C, Sawabe Y, Marunaka Y, Kuwabara H, Takahashi Y, Ito S, Nakahari T. A PKG inhibitor increases Ca(2+)-regulated exocytosis in guinea pig antral mucous cells: cAMP accumulation via PDE2A inhibition. Am J Physiol Gastrointest Liver Physiol 2013; 304:G773-80. [PMID: 23449671 DOI: 10.1152/ajpgi.00281.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In antral mucous cells, acetylcholine (ACh, 1 μM) activates Ca(2+)-regulated exocytosis, consisting of an initial peak that declines rapidly (initial transient phase) followed by a second slower decline (late phase) lasting during ACh stimulation. The addition of 8-bromo-cGMP (8-BrcGMP) enhanced the initial phase, which was inhibited by the protein kinase G (PKG) inhibitor guanosine 3',5'-cyclic monophosphorothoiate, β-phenyl-1,N(2)-etheno-8-bromo, Rp-isomer, sodium salt (Rp-8-BrPETcGMPS, 100 nM). However, Rp-8-BrPETcGMPS produced a delayed, but transient, increase in the exocytotic frequency during the late phase that was abolished by a protein kinase A (PKA) inhibitor (PKI-amide), suggesting that Rp-8-BrPETcGMPS accumulates cAMP. The cGMP-dependent phosphodiesterase 2 (PDE2), which degrades cAMP, may exist in antral mucous cells. The PDE2 inhibitor BAY-60-7550 (250 nM) mimicked the effect of Rp-8-BrPETcGMPS on ACh-stimulated exocytosis. Measurement of the cGMP and cAMP contents in antral mucosae revealed that ACh stimulates the accumulation of cGMP and that BAY-60-7550 accumulates cAMP similarly to Rp-8-BrPETcGMPS during ACh stimulation. Analyses of Western blot and immunohistochemistry demonstrated that PDE2A exists in antral mucous cells. In conclusion, Rp-8-BrPETcGMPS accumulates cAMP by inhibiting PDE2 in ACh-stimulated antral mucous cells, leading to the delayed, but transient, increase in the frequency of Ca(2+)-regulated exocytosis. PDE2 may prevent antral mucous cells from excessive mucin secretion caused by the cAMP accumulation.
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Affiliation(s)
- Saori Tanaka
- Nakahari Project of Central Research Laboratory, Osaka Medical College, Takatsuki, Japan
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Gasulla J, Beltrán González AN, Calvo DJ. Nitric oxide potentiation of the homomeric ρ1 GABA(C) receptor function. Br J Pharmacol 2013; 167:1369-77. [PMID: 22747884 DOI: 10.1111/j.1476-5381.2012.02087.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE NO is a highly diffusible and reactive gas produced in the nervous system, which acts as a neuronal signal mediating physiological or pathological mechanisms. NO can modulate the activity of neurotransmitter receptors and ion channels, including NMDA and GABA(A) receptors. In the present work, we examined whether GABA(C) receptor function can also be regulated by NO. EXPERIMENTAL APPROACH Homomeric ρ1 GABA(C) receptors were expressed in oocytes and GABA-evoked responses electrophysiologically recorded in the presence or absence of the NO donor DEA. Chemical protection of cysteines by selective sulfhydryl reagents and site-directed mutagenesis were used to determine the protein residues involved in the actions of NO. KEY RESULTS GABAρ1 receptor responses were significantly enhanced in a dose-dependent, fast and reversible manner by DEA and the specific NO scavenger CPTIO prevented these potentiating effects. The ρ1 subunits contain only three cysteine residues, two extracellular at the Cys-loop (C177 and C191) and one intracellular (C364). Mutations of C177 and C191 render the ρ1 GABA receptors non-functional, but C364 can be safely exchanged by alanine (C364A). NEM, N-ethyl maleimide and (2-aminoethyl) methanethiosulfonate prevented the effects of DEA on GABAρ1 receptors. Meanwhile, the potentiating effects of DEA on mutant GABAρ1(C364A) receptors were similar to those observed on wild-type receptors. CONCLUSIONS AND IMPLICATIONS Our results suggest that the function of GABA(C) receptors can be enhanced by NO acting at the extracellular Cys-loop.
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Affiliation(s)
- J Gasulla
- Laboratorio de Neurobiología Celular y Molecular, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
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Blom J, Giove TJ, Pong WW, Blute TA, Eldred WD. Evidence for a functional adrenomedullin signaling pathway in the mouse retina. Mol Vis 2012; 18:1339-53. [PMID: 22690112 PMCID: PMC3369892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 05/27/2012] [Indexed: 10/29/2022] Open
Abstract
PURPOSE Adrenomedullin (ADM) is a small, secreted peptide often associated with vasodilation. However, ADM can also function as a neurotransmitter/neuromodulator, and studies suggest ADM is upregulated in the eye in several ocular diseases. However, no studies to date have described an ADM signaling pathway in the retina. METHODS PCR, immunocytochemistry, nitric oxide imaging, western blots, and a nitrite assay were used to determine the localization of the components of the ADM signaling pathway in the mouse retina. RESULTS We used reverse-transcriptase polymerase chain reaction to show that ADM and its primary receptor, calcitonin-receptor-like receptor, along with its associated receptor activity modifying proteins 2 and 3 are expressed in the retina. Using immunocytochemistry, we detected ADM staining throughout the retina in the photoreceptor outer segments, the outer nuclear layer, Müller and amacrine cell somata in the inner nuclear layer, and some somata in the ganglion cell layer. We found that calcitonin-receptor-like receptor and receptor activity modifying protein 2 had localization patterns similar to ADM, especially in somata in the inner nuclear and ganglion cell layers. Finally, we showed that the ADM receptor was functional in the retina. Stimulation of isolated retinas with ADM increased cyclic adenosine monophosphate- and cyclic guanosine monophosphate-like immunoreactivity, as well as nitric oxide production. CONCLUSIONS These results are the first to show that ADM and functional ADM receptors are present in the retina. Since ADM is increased in eyes with ocular pathologies such as diabetic retinopathy, glaucoma, retinitis pigmentosa, and uveitis, the ADM signaling pathway may provide a new target for ameliorating these retinal pathologies.
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Vielma AH, Retamal MA, Schmachtenberg O. Nitric oxide signaling in the retina: what have we learned in two decades? Brain Res 2011; 1430:112-25. [PMID: 22133309 DOI: 10.1016/j.brainres.2011.10.045] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 10/14/2011] [Accepted: 10/27/2011] [Indexed: 01/21/2023]
Abstract
Two decades after its first detection in the retina, nitric oxide (NO) continues to puzzle visual neuroscientists. While its liberation by photoreceptors remains controversial, recent evidence supports three subtypes of amacrine cells as main sources of NO in the inner retina. NO synthesis was shown to depend on light stimulation, and mounting evidence suggests that NO is a regulator of visual adaptation at different signal processing levels. NO modulates light responses in all retinal neuron classes, and specific ion conductances are activated by NO in rods, cones, bipolar and ganglion cells. Light-dependent gap junction coupling in the inner and outer plexiform layers is also affected by NO. The vast majority of these effects were shown to be mediated by activation of the NO receptor soluble guanylate cyclase and resultant cGMP elevation. This review analyzes the current state of knowledge on physiological NO signaling in the retina.
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Affiliation(s)
- Alex H Vielma
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Nemargut JP, Wang GY. Inhibition of nitric oxide synthase desensitizes retinal ganglion cells to light by diminishing their excitatory synaptic currents under light adaptation. Vision Res 2009; 49:2936-47. [PMID: 19772868 DOI: 10.1016/j.visres.2009.09.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 09/11/2009] [Accepted: 09/16/2009] [Indexed: 10/20/2022]
Abstract
The effect of inhibiting nitric oxide synthase (NOS) on the visual responses of mouse retinal ganglion cells (RGCs) was studied under light adaptation by using patch-clamp recordings. The results demonstrated that NOS inhibitor, l-NAME, reduced the sensitivity of RGCs to light under light adaptation at different ambient light conditions. These observations were seen in all cells that recordings were made from. l-NAME diminished the excitatory synaptic currents (EPSCs), rather than increasing the inhibitory synaptic currents, of RGCs to reduce the sensitivity of RGCs to light. Cones may be the sites that l-NAME acted to diminish the EPSCs of RGCs.
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Affiliation(s)
- Joseph P Nemargut
- Department of Structural and Cellular Biology, School of Medicine, Tulane University, New Orleans, LA 70112, United States
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Abstract
Nitric oxide (NO) is a gaseous neuromodulator that has physiological functions in every cell type in the retina. Evidence indicates that NO often plays a role in the processing of visual information in the retina through the second messenger cyclic guanosine monophosphate (cGMP). Despite numerous structural and functional studies of this signaling pathway in the retina, none have examined many of the elements of this pathway within a single study in a single species. In this study, the NO/cGMP pathway was localized to specific regions and cell types within the inner and outer retina. We have immunocytochemically localized nitric oxide synthase, the enzyme that produces NO, in photoreceptor ellipsoids, four distinct classes of amacrine cells, Müller and bipolar cells, somata in the ganglion cell layer, as well as in processes within both plexiform layers. Additionally, we localized NO production in specific cell types using the NO-sensitive dye diaminofluorescein. cGMP immunocytochemistry was used to functionally localize soluble guanylate cyclase that was activated by an NO donor in select amacrine and bipolar cell classes. Analysis of cGMP and its downstream target, cGMP-dependent protein kinase II (PKGII), showed colocalization within processes in the outer retina as well as in somata in the inner retina. The results of this study showed that the NO/cGMP signaling pathway was functional and its components were widely distributed throughout specific cell types in the outer and inner salamander retina.
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Cimini BA, Strang CE, Wotring VE, Keyser KT, Eldred WD. Role of acetylcholine in nitric oxide production in the salamander retina. J Comp Neurol 2008; 507:1952-63. [PMID: 18273886 DOI: 10.1002/cne.21655] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Although acetylcholine is one of the most widely studied neurotransmitters in the retina, many questions remain about its downstream signaling mechanisms. In this study we initially characterized the cholinergic neurotransmitter system in the salamander retina by localizing a variety of cholinergic markers. We then examined the link between both muscarinic and nicotinic receptor activation and nitric oxide production by using immunocytochemistry for cyclic guanosine monophosphate (cGMP) as an indicator. We found a large increase in cGMP-like immunoreactivity (cGMP-LI) in the inner retina in response to muscarinic (but not nicotinic) receptor activation. Based on the amplification of mRNA transcripts, receptor immunocytochemistry, and the use of selective antagonists, we identified these receptors as M2 muscarinic receptors. Using double-labeling techniques, we established that these increases in cGMP-LI were seen in GABAergic but not cholinergic amacrine cells, and that the increases were blocked by inhibitors of nitric oxide production. The creation of nitric oxide in response to cholinergic receptor activation may provide a mechanism for modulating the well-known mutual interactions of acetylcholine-glycine-GABA in the inner retina. As GABA and glycine are the primary inhibitory neurotransmitters in the retina, signaling pathways that modulate their levels or release will have major implications for the processing of complex stimuli by the retina.
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Affiliation(s)
- Beth A Cimini
- Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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Poon RCC, Agnihotri N, Seymour C, Mothersill C. Bystander effects of ionizing radiation can be modulated by signaling amines. ENVIRONMENTAL RESEARCH 2007; 105:200-11. [PMID: 17291485 DOI: 10.1016/j.envres.2006.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 12/07/2006] [Accepted: 12/18/2006] [Indexed: 05/13/2023]
Abstract
Actual risk and risk management of exposure to ionizing radiation are among the most controversial areas in environmental health protection. Recent developments in radiobiology especially characterization of bystander effects have called into question established dogmas and are thought to cast doubt on the scientific basis of the risk assessment framework, leading to uncertainty for regulators and concern among affected populations. In this paper we test the hypothesis that small signaling molecules widely used throughout the animal kingdom for signaling stress or environmental change, such as 5-Hydroxytryptamine (5-HT, serotonin), l-DOPA, glycine or nicotine are involved in bystander signaling processes following ionizing radiation exposure. We report data which suggest that nano to micromolar concentrations of these agents can modulate bystander-induced cell death. Depletion of 5-HT present in tissue culture medium, occurred following irradiation of cells. This suggested that 5-HT might be bound by membrane receptors after irradiation. Expression of 5-HT type 3 receptors which are Ca(2+) ion channels was confirmed in the cells using immunocytochemistry and receptor expression could be increased using radiation or 5-HT exposure. Zofran and Kitryl, inhibitors of 5-HT type 3 receptors, and reserpine a generic serotonin antagonist block the bystander effect induced by radiation or by serotonin. The results may be important for the mechanistic understanding of how low doses of radiation interact with cells to produce biological effects.
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Affiliation(s)
- R C C Poon
- Department of Medical Physics and Applied Radiation Sciences, Juravinski Cancer Centre, McMaster University, Hamilton, Ont., Canada
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