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Iwahashi M, Yoshimura T, Harigai W, Takuma K, Hashimoto H, Katayama T, Hayata-Takano A. Pituitary adenylate cyclase-activating polypeptide deficient mice show length abnormalities of the axon initial segment. J Pharmacol Sci 2023; 153:175-182. [PMID: 37770159 DOI: 10.1016/j.jphs.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/25/2023] [Indexed: 10/03/2023] Open
Abstract
We previously found that pituitary adenylate cyclase-activating polypeptide (PACAP)-deficient (PACAP-/-) mice exhibit dendritic spine morphology impairment and neurodevelopmental disorder (NDD)-like behaviors such as hyperactivity, increased novelty-seeking behavior, and deficient pre-pulse inhibition. Recent studies have indicated that rodent models of NDDs (e.g., attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder) show abnormalities in the axon initial segment (AIS). Here, we revealed that PACAP-/- mice exhibited a longer AIS length in layer 2/3 pyramidal neurons of the primary somatosensory barrel field compared with wild-type control mice. Further, we previously showed that a single injection of atomoxetine, an ADHD drug, improved hyperactivity in PACAP-/- mice. In this study, we found that repeated treatments of atomoxetine significantly improved AIS abnormality along with hyperactivity in PACAP-/- mice. These results suggest that AIS abnormalities are associated with NDDs-like behaviors in PACAP-/- mice. Thus, improvement in AIS abnormalities will be a novel drug therapy for NDDs.
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Affiliation(s)
- Misaki Iwahashi
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takeshi Yoshimura
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Wakana Harigai
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuhiro Takuma
- Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hitoshi Hashimoto
- Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan; Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan; Division of Bioscience, Institute for Datability Science, Osaka University, 2-8 Yamadaoka, Suita, Osaka, 565-0871, Japan; Department of Molecular Pharmaceutical Science, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taiichi Katayama
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Atsuko Hayata-Takano
- Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Kraus A, Garcia B, Ma J, Herrera KJ, Zwaka H, Harpaz R, Wong RY, Engert F, Salinas I. Olfactory detection of viruses shapes brain immunity and behavior in zebrafish. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.533129. [PMID: 37034630 PMCID: PMC10081220 DOI: 10.1101/2023.03.17.533129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Olfactory sensory neurons (OSNs) are constantly exposed to pathogens, including viruses. However, serious brain infection via the olfactory route rarely occurs. When OSNs detect a virus, they coordinate local antiviral immune responses to stop virus progression to the brain. Despite effective immune control in the olfactory periphery, pathogen-triggered neuronal signals reach the CNS via the olfactory bulb (OB). We hypothesized that neuronal detection of a virus by OSNs initiates neuroimmune responses in the OB that prevent pathogen invasion. Using zebrafish ( Danio rerio ) as a model, we demonstrate viral-specific neuronal activation of OSNs projecting into the OB, indicating that OSNs are electrically activated by viruses. Further, behavioral changes are seen in both adult and larval zebrafish after viral exposure. By profiling the transcription of single cells in the OB after OSNs are exposed to virus, we found that both microglia and neurons enter a protective state. Microglia and macrophage populations in the OB respond within minutes of nasal viral delivery followed decreased expression of neuronal differentiation factors and enrichment of genes in the neuropeptide signaling pathway in neuronal clusters. Pituitary adenylate-cyclase-activating polypeptide ( pacap ), a known antimicrobial, was especially enriched in a neuronal cluster. We confirm that PACAP is antiviral in vitro and that PACAP expression increases in the OB 1 day post-viral treatment. Our work reveals how encounters with viruses in the olfactory periphery shape the vertebrate brain by inducing antimicrobial programs in neurons and by altering host behavior.
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Xu W, Wang Y, Qi X, Li K, Zhou L, Sha S, Wang X, Wu C, Du Y, Chen L. Involvement of TRPV4 in changes in rapidly inactivating potassium channels in the early stage of pilocarpine-induced status epilepticus in mice. J Cell Physiol 2021; 237:856-867. [PMID: 34415059 DOI: 10.1002/jcp.30558] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 08/06/2021] [Accepted: 08/11/2021] [Indexed: 11/11/2022]
Abstract
The rapidly inactivating potassium current (IA ) is important in controlling neuronal action potentials. Altered IA function and K+ channel expression have been found in epilepsy, and activation of the transient receptor potential vanilloid 4 (TRPV4) channel is involved in epilepsy pathogenesis. This study examined whether TRPV4 affects Kv4.2 and K+ channel interacting protein (KCHIP) expression and IA changes following pilocarpine-induced status epilepticus (PISE) in mice. Herein, hippocampal protein levels of Kv4.2 and KCHIP2 increased 3 h-3 d and decreased 7-30 d; that of KCHIP1 increased 3-24 h and decreased 3-30 d post-PISE. The TRPV4 antagonist HC-067047 attenuated the increased protein levels of Kv4.2 and KCHIP2 but not that of KCHIP1 post-PISE. The TRPV4 agonist GSK1016790A increased hippocampal protein levels of Kv4.2 and KCHIP2 but had no effect on KCHIP1 expression. HC-067047 attenuated the increased IA in hippocampal pyramidal neurons 24 h and 3 d post-PISE. GSK1016790A increased IA in hippocampal pyramidal neurons, shifting the voltage-dependent inactivation curve toward depolarization. The GSK1016790A-induced increase of IA was blocked by protein kinase A and calcium/calmodulin-dependent kinase II antagonists but was unaffected by protein kinase C antagonists. We conclude that TRPV4 activation may be responsible for the increases of Kv4.2 and KCHIP2 expression in hippocampi and IA in hippocampal pyramidal neurons in PISE mice, which are likely compensatory measures for hyperexcitability at the early stage of epilepsy.
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Affiliation(s)
- Weixing Xu
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Yue Wang
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Xiuting Qi
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Kunpeng Li
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Li Zhou
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Sha Sha
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Xiaoli Wang
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Chunfeng Wu
- Department of Neurology, Children's Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Yimei Du
- Department of cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Lei Chen
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
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Solés-Tarrés I, Cabezas-Llobet N, Vaudry D, Xifró X. Protective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide and Vasoactive Intestinal Peptide Against Cognitive Decline in Neurodegenerative Diseases. Front Cell Neurosci 2020; 14:221. [PMID: 32765225 PMCID: PMC7380167 DOI: 10.3389/fncel.2020.00221] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 06/22/2020] [Indexed: 12/23/2022] Open
Abstract
Cognitive impairment is one of the major symptoms in most neurodegenerative disorders such as Alzheimer’s (AD), Parkinson (PD), and Huntington diseases (HD), affecting millions of people worldwide. Unfortunately, there is no treatment to cure or prevent the progression of those diseases. Cognitive impairment has been related to neuronal cell death and/or synaptic plasticity alteration in important brain regions, such as the cerebral cortex, substantia nigra, striatum, and hippocampus. Therefore, compounds that can act to protect the neuronal loss and/or to reestablish the synaptic activity are needed to prevent cognitive decline in neurodegenerative diseases. Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are two highly related multifunctional neuropeptides widely distributed in the central nervous system (CNS). PACAP and VIP exert their action through two common receptors, VPAC1 and VPAC2, while PACAP has an additional specific receptor, PAC1. In this review article, we first presented evidence showing the therapeutic potential of PACAP and VIP to fight the cognitive decline observed in models of AD, PD, and HD. We also reviewed the main transduction pathways activated by PACAP and VIP receptors to reduce cognitive dysfunction. Furthermore, we identified the therapeutic targets of PACAP and VIP, and finally, we evaluated different novel synthetic PACAP and VIP analogs as promising pharmacological tools.
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Affiliation(s)
- Irene Solés-Tarrés
- New Therapeutic Targets Group (TargetsLab), Department of Medical Science, Faculty of Medicine, Universitat de Girona, Girona, Spain
| | - Núria Cabezas-Llobet
- New Therapeutic Targets Group (TargetsLab), Department of Medical Science, Faculty of Medicine, Universitat de Girona, Girona, Spain
| | - David Vaudry
- Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, Neuropeptides, Neuronal Death and Cell Plasticity Team, Normandie University, UNIROUEN, Inserm, Rouen, France
| | - Xavier Xifró
- New Therapeutic Targets Group (TargetsLab), Department of Medical Science, Faculty of Medicine, Universitat de Girona, Girona, Spain
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Johnson GC, May V, Parsons RL, Hammack SE. Parallel signaling pathways of pituitary adenylate cyclase activating polypeptide (PACAP) regulate several intrinsic ion channels. Ann N Y Acad Sci 2019; 1455:105-112. [PMID: 31162688 DOI: 10.1111/nyas.14116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/27/2019] [Accepted: 04/12/2019] [Indexed: 12/01/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP), acting through its cognate receptors PAC1, VPAC1, and VPAC2, is a pleiotropic signaling neuropeptide of the vasoactive intestinal peptide/secretin/glucagon family. PACAP has known functions in neuronal growth, development, and repair, and central PACAP signaling has acute behavioral consequences. One of the ways in which PACAP may affect neuronal function is through the modulation of intrinsic membrane currents to control neuronal excitability. Here, we review the evidence of PACAP-dependent modulation of calcium- and voltage-gated potassium currents, hyperpolarization-activated cation currents, calcium currents, and voltage-gated sodium currents. Interestingly, PACAP signaling pathways diverge into parallel pathways to target different ionic currents for modulation, though single pathways are not limited to modulating just one target ionic current. Despite the various targets of modulation, the weight of the evidence suggests that PACAP signaling most commonly leads to a net increase in neuronal excitability. We discuss possible mechanisms by which PACAP signaling leads to the modulation of intrinsic membrane currents that may contribute to changes in behavior.
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Affiliation(s)
- Gregory C Johnson
- Department of Psychological Science, University of Vermont, Burlington, Vermont
| | - Victor May
- Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Rodney L Parsons
- Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Sayamwong E Hammack
- Department of Psychological Science, University of Vermont, Burlington, Vermont
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Tompkins JD, Clason TA, Hardwick JC, Girard BM, Merriam LA, May V, Parsons RL. Activation of MEK/ERK signaling contributes to the PACAP-induced increase in guinea pig cardiac neuron excitability. Am J Physiol Cell Physiol 2016; 311:C643-C651. [PMID: 27488668 DOI: 10.1152/ajpcell.00164.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/01/2016] [Indexed: 01/12/2023]
Abstract
Pituitary adenylate cyclase (PAC)-activating polypeptide (PACAP) peptides (Adcyap1) signaling at the selective PAC1 receptor (Adcyap1r1) participate in multiple homeostatic and stress-related responses, yet the cellular mechanisms underlying PACAP actions remain to be completely elucidated. PACAP/PAC1 receptor signaling increases excitability of neurons within the guinea pig cardiac ganglia, and as these neurons are readily accessible, this neuronal system is particularly amenable to study of PACAP modulation of ionic conductances. The present study investigated how PACAP activation of MEK/ERK signaling contributed to the peptide-induced increase in cardiac neuron excitability. Treatment with the MEK inhibitor PD 98059 blocked PACAP-stimulated phosphorylated ERK and, in parallel, suppressed the increase in cardiac neuron excitability. However, PD 98059 did not blunt the ability of PACAP to enhance two inward ionic currents, one flowing through hyperpolarization-activated nonselective cationic channels (Ih) and another flowing through low-voltage-activated calcium channels (IT), which support the peptide-induced increase in excitability. Thus a PACAP- and MEK/ERK-sensitive, voltage-dependent conductance(s), in addition to Ih and IT, modulates neuronal excitability. Despite prior work implicating PACAP downregulation of the KV4.2 potassium channel in modulation of excitability in other cells, treatment with the KV4.2 current blocker 4-aminopyridine did not replicate the PACAP-induced increase in excitability in cardiac neurons. However, cardiac neurons express the ERK target, the NaV1.7 sodium channel, and treatment with the selective NaV1.7 channel inhibitor PF-04856264 decreased the PACAP modulation of excitability. From these results, PACAP/PAC1 activation of MEK/ERK signaling may phosphorylate the NaV1.7 channel, enhancing sodium currents near the threshold, an action contributing to repetitive firing of the cardiac neurons exposed to PACAP.
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Affiliation(s)
- John D Tompkins
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California
| | - Todd A Clason
- Department of Neurological Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | | | - Beatrice M Girard
- Department of Neurological Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Laura A Merriam
- Department of Neurological Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Victor May
- Department of Neurological Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Rodney L Parsons
- Department of Neurological Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
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Gupte RP, Kadunganattil S, Shepherd AJ, Merrill R, Planer W, Bruchas MR, Strack S, Mohapatra DP. Convergent phosphomodulation of the major neuronal dendritic potassium channel Kv4.2 by pituitary adenylate cyclase-activating polypeptide. Neuropharmacology 2015; 101:291-308. [PMID: 26456351 DOI: 10.1016/j.neuropharm.2015.10.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 09/29/2015] [Accepted: 10/03/2015] [Indexed: 12/30/2022]
Abstract
The endogenous neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) is secreted by both neuronal and non-neuronal cells in the brain and spinal cord, in response to pathological conditions such as stroke, seizures, chronic inflammatory and neuropathic pain. PACAP has been shown to exert various neuromodulatory and neuroprotective effects. However, direct influence of PACAP on the function of intrinsically excitable ion channels that are critical to both hyperexcitation as well as cell death, remain largely unexplored. The major dendritic K(+) channel Kv4.2 is a critical regulator of neuronal excitability, back-propagating action potentials in the dendrites, and modulation of synaptic inputs. We identified, cloned and characterized the downstream signaling originating from the activation of three PACAP receptor (PAC1) isoforms that are expressed in rodent hippocampal neurons that also exhibit abundant expression of Kv4.2 protein. Activation of PAC1 by PACAP leads to phosphorylation of Kv4.2 and downregulation of channel currents, which can be attenuated by inhibition of either PKA or ERK1/2 activity. Mechanistically, this dynamic downregulation of Kv4.2 function is a consequence of reduction in the density of surface channels, without any influence on the voltage-dependence of channel activation. Interestingly, PKA-induced effects on Kv4.2 were mediated by ERK1/2 phosphorylation of the channel at two critical residues, but not by direct channel phosphorylation by PKA, suggesting a convergent phosphomodulatory signaling cascade. Altogether, our findings suggest a novel GPCR-channel signaling crosstalk between PACAP/PAC1 and Kv4.2 channel in a manner that could lead to neuronal hyperexcitability.
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Affiliation(s)
- Raeesa P Gupte
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Suraj Kadunganattil
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Andrew J Shepherd
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Ronald Merrill
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - William Planer
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael R Bruchas
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Stefan Strack
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Durga P Mohapatra
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Han P, Caselli RJ, Baxter L, Serrano G, Yin J, Beach TG, Reiman EM, Shi J. Association of pituitary adenylate cyclase-activating polypeptide with cognitive decline in mild cognitive impairment due to Alzheimer disease. JAMA Neurol 2015; 72:333-9. [PMID: 25599520 DOI: 10.1001/jamaneurol.2014.3625] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
IMPORTANCE There is a deficit of pituitary adenylate cyclase-activating polypeptide (PACAP) in patients with neuropathologically confirmed Alzheimer dementia. However, whether this deficit is associated with the earlier stages of Alzheimer disease (AD) is unknown. This study was conducted to clarify the association between PACAP biomarkers and preclinical, mild cognitive impairment (MCI), and dementia stages of AD in postmortem brain tissue. OBJECTIVES To examine PACAP and PACAP receptor levels in postmortem brain tissues and cerebrospinal fluid from cognitively and neuropathologically normal control individuals, patients with MCI due to AD (MCI-AD), and individuals with AD; analyze the relationship between PACAP, cognitive, and pathologic features; and propose a model to assess these relationships. DESIGN, SETTING, AND PARTICIPANTS We measured PACAP and its receptor (PAC1) levels using enzyme-linked immunoassay. A total of 35 cases were included. All the brain tissue and cerebrospinal fluid samples were selected from Banner Sun Health Research Institute Brain and Body Donation Program. All cognitive test results were in record with the Arizona Alzheimer's Consortium. MAIN OUTCOMES AND MEASURES A comparison of PACAP and PAC1 levels among the healthy controls, MCI-AD, and AD dementia groups, as well as a systematic correlation analysis between PACAP level, cognitive performance, and pathologic severity. RESULTS The PACAP levels in cerebrospinal fluid, the superior frontal gyrus, and the middle temporal gyrus were inversely related to dementia severity. The PACAP levels in cerebrospinal fluid correlated with the Mattis Dementia Rating Scale score (Pearson r = 0.50; P = .03) and inversely correlated with total amyloid plaques (Pearson r = -0.48; P < .01) and tangles (Pearson r = -0.55; P = .01) in the brain. The PACAP in the superior frontal gyrus and middle temporal gyrus correlated with the Stroop Color-Word Interference Test (Pearson r = 0.58; P < .01) and the Auditory Verbal Learning Test-Total Learning (Pearson r = 0.33; P = .02), respectively. The PACAP in the primary visual cortex did not correlate with the Judgment of Line orientation test (P = .14). Furthermore, the PAC1 level in the superior frontal gyrus showed an upregulation in MCI-AD but not in AD. The pharmacodynamic model of the PACAP-PAC1 interaction best predicted cognitive function in the superior frontal gyrus, but it was less predictive in the middle temporal gyrus and failed to be predictive in the primary visual cortex. CONCLUSIONS AND RELEVANCE Deficits in PACAP are associated with clinical severity in the MCI and dementia stages of AD. Additional studies are needed to clarify the role of PACAP deficits in the predisposition to, pathogenesis of, and treatment of AD.
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Affiliation(s)
- Pengcheng Han
- Barrow Neurological Institute, Dignity Health Organization, St Joseph's Hospital and Medical Center, Phoenix, Arizona
| | | | - Leslie Baxter
- Barrow Neurological Institute, Dignity Health Organization, St Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Geidy Serrano
- Civin Laboratory for Neuropathology, Banner Sun Health Research Institute, Sun City, Arizona
| | - Junxiang Yin
- Barrow Neurological Institute, Dignity Health Organization, St Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Thomas G Beach
- Civin Laboratory for Neuropathology, Banner Sun Health Research Institute, Sun City, Arizona
| | | | - Jiong Shi
- Barrow Neurological Institute, Dignity Health Organization, St Joseph's Hospital and Medical Center, Phoenix, Arizona
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Irwin M, Greig A, Tvrdik P, Lucero MT. PACAP modulation of calcium ion activity in developing granule cells of the neonatal mouse olfactory bulb. J Neurophysiol 2014; 113:1234-48. [PMID: 25475351 DOI: 10.1152/jn.00594.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca(2+) activity in the CNS is critical for the establishment of developing neuronal circuitry prior to and during early sensory input. In developing olfactory bulb (OB), the neuromodulators that enhance network activity are largely unknown. Here we provide evidence that pituitary adenylate cyclase-activating peptide (PACAP)-specific PAC1 receptors (PAC1Rs) expressed in postnatal day (P)2-P5 mouse OB are functional and enhance network activity as measured by increases in calcium in genetically identified granule cells (GCs). We used confocal Ca(2+) imaging of OB slices from Dlx2-tdTomato mice to visualize GABAergic GCs. To address whether the PACAP-induced Ca(2+) oscillations were direct or indirect effects of PAC1R activation, we used antagonists for the GABA receptors (GABARs) and/or glutamate receptors (GluRs) in the presence and absence of PACAP. Combined block of GABARs and GluRs yielded a 66% decrease in the numbers of PACAP-responsive cells, suggesting that 34% of OB neurons are directly activated by PACAP. Similarly, immunocytochemistry using anti-PAC1 antibody showed that 34% of OB neurons express PAC1R. Blocking either GluRs or GABARs alone indirectly showed that PACAP stimulates release of both glutamate and GABA, which activate GCs. The appearance of PACAP-induced Ca(2+) activity in immature GCs suggests a role for PACAP in GC maturation. To conclude, we find that PACAP has both direct and indirect effects on neonatal OB GABAergic cells and may enhance network activity by promoting glutamate and GABA release. Furthermore, the numbers of PACAP-responsive GCs significantly increased between P2 and P5, suggesting that PACAP-induced Ca(2+) activity contributes to neonatal OB development.
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Affiliation(s)
- Mavis Irwin
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah
| | - Ann Greig
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah
| | - Petr Tvrdik
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah; Interdepartmental Neuroscience Program, University of Utah School of Medicine, Salt Lake City, Utah; and
| | - Mary T Lucero
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah; Interdepartmental Neuroscience Program, University of Utah School of Medicine, Salt Lake City, Utah; and Department of Neuroscience and Physiology, American University of the Caribbean, Cupecoy, Sint Maarten, Netherlands Antilles
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10
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Szebenyi SA, Ogura T, Sathyanesan A, AlMatrouk AK, Chang J, Lin W. Increases in intracellular calcium via activation of potentially multiple phospholipase C isozymes in mouse olfactory neurons. Front Cell Neurosci 2014; 8:336. [PMID: 25374507 PMCID: PMC4204526 DOI: 10.3389/fncel.2014.00336] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/01/2014] [Indexed: 11/13/2022] Open
Abstract
Phospholipase C (PLC) and internal Ca(2+) stores are involved in a variety of cellular functions. However, our understanding of PLC in mammalian olfactory sensory neurons (OSNs) is generally limited to its controversial role in odor transduction. Here we employed single-cell Ca(2+) imaging and molecular approaches to investigate PLC-mediated Ca(2+) responses and its isozyme gene transcript expression. We found that the pan-PLC activator m-3M3FBS (25 μM) induces intracellular Ca(2+) increases in vast majority of isolated mouse OSNs tested. Both the response amplitude and percent responding cells depend on m-3M3FBS concentrations. In contrast, the inactive analog o-3M3FBS fails to induce Ca(2+) responses. The m-3M3FBS-induced Ca(2+) increase is blocked by the PLC inhibitor U73122, while its inactive analog U73433 has no effect. Removal of extracellular Ca(2+) does not change significantly the m-3M3FBS-induced Ca(2+) response amplitude. Additionally, in the absence of external Ca(2+), we found that a subset of OSNs respond to an odorant mixture with small Ca(2+) increases, which are significantly suppressed by U73122. Furthermore, using reverse transcription polymerase chain reaction and real-time quantitative polymerase chain reaction, we found that multiple PLC isozyme gene transcripts are expressed in olfactory turbinate tissue in various levels. Using RNA in situ hybridization analysis, we further show expression of β4, γ1, γ2 gene transcripts in OSNs. Taken together, our results establish that PLC isozymes are potent enzymes for mobilizing intracellular Ca(2+) in mouse OSNs and provide molecular insight for PLC isozymes-mediated complex cell signaling and regulation in the peripheral olfactory epithelium.
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Affiliation(s)
- Steven A Szebenyi
- Department of Biological Sciences, University of Maryland Baltimore County Baltimore, MD, USA
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland Baltimore County Baltimore, MD, USA
| | - Aaron Sathyanesan
- Department of Biological Sciences, University of Maryland Baltimore County Baltimore, MD, USA
| | - Abdullah K AlMatrouk
- Department of Biological Sciences, University of Maryland Baltimore County Baltimore, MD, USA
| | - Justin Chang
- Department of Biological Sciences, University of Maryland Baltimore County Baltimore, MD, USA
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland Baltimore County Baltimore, MD, USA
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Nemeth A, Szabadfi K, Fulop B, Reglodi D, Kiss P, Farkas J, Szalontai B, Gabriel R, Hashimoto H, Tamas A. Examination of calcium-binding protein expression in the inner ear of wild-type, heterozygous and homozygous pituitary adenylate cyclase-activating polypeptide (PACAP)-knockout mice in kanamycin-induced ototoxicity. Neurotox Res 2013; 25:57-67. [PMID: 24155155 DOI: 10.1007/s12640-013-9428-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/23/2013] [Accepted: 09/24/2013] [Indexed: 11/24/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with diverse biological effects. It also occurs and exerts protective effects in sensory organs; however, little is known about its effects in the auditory system. Recently, we have shown that PACAP protects cochlear cells against oxidative-stress-induced apoptosis and homozygous PACAP-deficient animals show stronger expression of Ca(2+)-binding proteins in the hair cells of the inner ear, but there are no data about the consequences of the lack of endogenous PACAP in different ototoxic insults such as aminoglycoside-induced toxicity. In this study, we examined the effect of kanamycin treatment on Ca(2+)-binding protein expression in hair cells of wild-type, heterozygous and homozygous PACAP-deficient mice. We treated 5-day-old mice with kanamycin, and 2 days later, we examined the Ca(2+)-binding protein expression of the hair cells with immunohistochemistry. We found stronger expression of Ca(2+)-binding proteins in the hair cells of control heterozygous and homozygous PACAP-deficient mice compared with wild-type animals. Kanamycin induced a significant increase in Ca(2+)-binding protein expression in wild-type and heterozygous PACAP-deficient mice, but the baseline higher expression in homozygous PACAP-deficient mice did not show further changes after the treatment. Elevated endolymphatic Ca(2+) is deleterious for the cochlear function, against which the high concentration of Ca(2+)-buffers in hair cells may protect. Meanwhile, the increased immunoreactivity of Ca(2+)-binding proteins in the absence of PACAP provide further evidence for the important protective role of PACAP in ototoxicity, but further investigations are necessary to examine the exact role of endogenous PACAP in ototoxic insults.
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Affiliation(s)
- A Nemeth
- Department of Oto-rhino-laryngology, University of Pecs, Pecs, Hungary
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12
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Gao S, Guo X, Liu T, Liu J, Chen W, Xia Q, Chen Y, Tang Y. Serotonin modulates outward potassium currents in mouse olfactory receptor neurons. Physiol Res 2013; 62:455-62. [PMID: 23590600 DOI: 10.33549/physiolres.932413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Monoaminergic neurotransmitter 5-hydroxytryptamine (5-HT), also known as serotonin, plays important roles in modulating the function of the olfactory system. However, thus far, the knowledge about 5-HT and its receptors in olfactory receptor neurons (ORNs) and their physiological role have not been fully characterized. In the present study, reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed the presence of 5-HT(1A) and 5-HT(1B) receptor subtypes in mouse olfactory epithelium at the mRNA level. With subtype selective antibodies and standard immunohistochemical techniques, both receptor subtypes were found to be positively labeled. To further elucidate the molecular mechanisms of 5-HT act on the peripheral olfactory transduction, the whole-cell patch clamp techniques were used on freshly isolated ORNs. We found that 5-HT decreased the magnitude of outward K(+) current in a dose-dependent manner and these inhibitory effects were markedly attenuated by the 5-HT(1A) receptor blocker WAY-100635 and the 5-HT(1B) receptor antagonist GR55562. These data suggested that 5-HT may play a role in the modulation of peripheral olfactory signals by regulating outward potassium currents, both 5-HT(1A) and 5-HT(1B) receptors were involved in this regulation.
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Affiliation(s)
- S Gao
- Department of Otorhinolaryngology and Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, China
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13
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Lucero MT. Peripheral modulation of smell: fact or fiction? Semin Cell Dev Biol 2012; 24:58-70. [PMID: 22986099 DOI: 10.1016/j.semcdb.2012.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 09/06/2012] [Indexed: 01/01/2023]
Abstract
Despite studies dating back 30 or more years showing modulation of odorant responses at the level of the olfactory epithelium, most descriptions of the olfactory system infer that odorant signals make their way from detection by cilia on olfactory sensory neurons to the olfactory bulb unaltered. Recent identification of multiple subtypes of microvillar cells and identification of neuropeptide and neurotransmitter expression in the olfactory mucosa add to the growing body of literature for peripheral modulation in the sense of smell. Complex mechanisms including perireceptor events, modulation of sniff rates, and changes in the properties of sensory neurons match the sensitivity of olfactory sensory neurons to the external odorant environment, internal nutritional status, reproductive status, and levels of arousal or stress. By furthering our understanding of the players mediating peripheral olfaction, we may open the door to novel approaches for modulating the sense of smell in both health and disease.
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Affiliation(s)
- Mary T Lucero
- Department of Physiology, School of Medicine, University of Utah, 420 Chipeta Way Ste, 1700 Salt Lake City, UT 84108, USA.
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14
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Tamas A, Szabadfi K, Nemeth A, Fulop B, Kiss P, Atlasz T, Gabriel R, Hashimoto H, Baba A, Shintani N, Helyes Z, Reglodi D. Comparative Examination of Inner Ear in Wild Type and Pituitary Adenylate Cyclase Activating Polypeptide (PACAP)-Deficient Mice. Neurotox Res 2011; 21:435-44. [DOI: 10.1007/s12640-011-9298-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Revised: 11/17/2011] [Accepted: 12/06/2011] [Indexed: 12/30/2022]
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15
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Fransén E, Tigerholm J. Role of A-type potassium currents in excitability, network synchronicity, and epilepsy. Hippocampus 2010; 20:877-87. [PMID: 19777555 DOI: 10.1002/hipo.20694] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A range of ionic currents have been suggested to be involved in distinct aspects of epileptogenesis. Based on pharmacological and genetic studies, potassium currents have been implicated, in particular the transient A-type potassium current (K(A)). Epileptogenic activity comprises a rich repertoire of characteristics, one of which is synchronized activity of principal cells as revealed by occurrences of for instance fast ripples. Synchronized activity of this kind is particularly efficient in driving target cells into spiking. In the recipient cell, this synchronized input generates large brief compound excitatory postsynaptic potentials (EPSPs). The fast activation and inactivation of K(A) lead us to hypothesize a potential role in suppression of such EPSPs. In this work, using computational modeling, we have studied the activation of K(A) by synaptic inputs of different levels of synchronicity. We find that K(A) participates particularly in suppressing inputs of high synchronicity. We also show that the selective suppression stems from the current's ability to become activated by potentials with high slopes. We further show that K(A) suppresses input mimicking the activity of a fast ripple. Finally, we show that the degree of selectivity of K(A) can be modified by changes to its kinetic parameters, changes of the type that are produced by the modulatory action of KChIPs and DPPs. We suggest that the wealth of modulators affecting K(A) might be explained by a need to control cellular excitability in general and suppression of responses to synchronicity in particular. Wealso suggest that compounds changing K(A)-kinetics may be used to pharmacologically improve epileptic status.
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Affiliation(s)
- Erik Fransén
- Department of Computational Biology, School of Computer Science and Communication, Royal Institute of Technology, AlbaNova University Center, Stockholm, Sweden.
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16
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Tong M, Hernandez JL, Purcell EK, Altschuler RA, Duncan RK. The intrinsic electrophysiological properties of neurons derived from mouse embryonic stem cells overexpressing neurogenin-1. Am J Physiol Cell Physiol 2010; 299:C1335-44. [PMID: 20861468 DOI: 10.1152/ajpcell.00207.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A mouse embryonic stem (ES) cell line containing an inducible transgene for the proneural gene Neurog1 has been used to generate glutamatergic neurons at a high efficiency. The present study used in vitro electrophysiology to establish the timeline for acquiring a functional neuronal phenotype in Neurog1-induced cells exhibiting a neuronal morphology. TTX-sensitive action potentials could be evoked from over 80% of the cells after only 4.5 days in vitro (DIV). These cells uniformly showed rapidly adapting responses to current injection, firing one to three action potentials at the onset of the stimulus. In the absence of Neurog1, a limited number of ES cells adopted a neuronal morphology, but these cells displayed slow calcium depolarizations rather than sodium-based spikes. Voltage-gated Na(+), K(+), and Ca(2+) currents were present in nearly all induced cells as early as 4.5 DIV. The voltage-dependent properties of these currents changed little from 4 to 12 DIV with half-activation voltage varying by <10 mV for any current type throughout the culture period. This study demonstrates that forced expression of proneural genes can induce ES cells to quickly acquire a functional neuronal phenotype with mature electrophysiological properties. Transient overexpression of Neurog1 may be used in neural repair strategies that require the rapid induction of functional neurons from pluripotent stem cells.
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Affiliation(s)
- Mingjie Tong
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, Michigan 48109-5616, USA
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17
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PACAP protects against TNFα-induced cell death in olfactory epithelium and olfactory placodal cell lines. Mol Cell Neurosci 2010; 45:345-54. [PMID: 20654718 DOI: 10.1016/j.mcn.2010.07.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 07/09/2010] [Accepted: 07/13/2010] [Indexed: 11/20/2022] Open
Abstract
In mouse olfactory epithelium (OE), pituitary adenylate cyclase-activating peptide (PACAP) protects against axotomy-induced apoptosis. We used mouse OE to determine whether PACAP protects neurons during exposure to the inflammatory cytokine TNFα. Live slices of neonatal mouse OE were treated with 40 ng/ml TNFα ± 40nM PACAP for 6h and dying cells were live-labeled with 0.5% propidium iodide. TNFα significantly increased the percentage of dying cells while co-incubation with PACAP prevented cell death. PACAP also prevented TNFα-mediated cell death in the olfactory placodal (OP) cell lines, OP6 and OP27. Although OP cell lines express all three PACAP receptors (PAC1, VPAC1,VPAC2), PACAP's protection of these cells from TNFα was mimicked by the specific PAC1 receptor agonist maxadilan and abolished by the PAC1 antagonist PACAP6-38. Treatment of OP cell lines with blockers or activators of the PLC and AC/MAPKK pathways revealed that PACAP-mediated protection from TNFα involved both pathways. PACAP may therefore function through PAC1 receptors to protect neurons from cell death during inflammatory cytokine release in vivo as would occur upon viral infection or allergic rhinitis-associated injury.
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18
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Pugh PC, Jayakar SS, Margiotta JF. PACAP/PAC1R signaling modulates acetylcholine release at neuronal nicotinic synapses. Mol Cell Neurosci 2009; 43:244-57. [PMID: 19958833 DOI: 10.1016/j.mcn.2009.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 11/18/2009] [Accepted: 11/19/2009] [Indexed: 12/11/2022] Open
Abstract
Neuropeptides collaborate with conventional neurotransmitters to regulate synaptic output. Pituitary adenylate cyclase-activating polypeptide (PACAP) co-localizes with acetylcholine in presynaptic nerve terminals, is released by stimulation, and enhances nicotinic acetylcholine receptor- (nAChR-) mediated responses. Such findings implicate PACAP in modulating nicotinic neurotransmission, but relevant synaptic mechanisms have not been explored. We show here that PACAP acts via selective high-affinity G-protein coupled receptors (PAC(1)Rs) to enhance transmission at nicotinic synapses on parasympathetic ciliary ganglion (CG) neurons by rapidly and persistently increasing the frequency and amplitude of spontaneous, impulse-dependent nicotinic excitatory postsynaptic currents (sEPSCs). Of the canonical adenylate cyclase (AC) and phospholipase-C (PLC) transduction cascades stimulated by PACAP/PAC(1)R signaling, only AC-generated signals are critical for synaptic modulation since the increases in sEPSC frequency and amplitude were mimicked by 8-Bromo-cAMP, blocked by inhibiting AC or cAMP-dependent protein kinase (PKA), and unaffected by inhibiting PLC. Despite its ability to increase agonist-induced nAChR currents, PACAP failed to influence nAChR-mediated impulse-independent miniature EPSC amplitudes (quantal size). Instead, evoked transmission assays reveal that PACAP/PAC(1)R signaling increased quantal content, indicating that it modulates synaptic function by increasing vesicular ACh release from presynaptic terminals. Lastly, signals generated by the retrograde messenger, nitric oxide- (NO-) are critical for the synaptic modulation since the PACAP-induced increases in spontaneous EPSC frequency, amplitude and quantal content were mimicked by NO donor and absent after inhibiting NO synthase (NOS). These results indicate that PACAP/PAC(1)R activation recruits AC-dependent signaling that stimulates NOS to increase NO production and control presynaptic transmitter output at neuronal nicotinic synapses.
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Affiliation(s)
- Phyllis C Pugh
- University of Toledo College of Medicine, Department of Neurosciences, Toledo, OH 43614-5804, USA
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19
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Serrano F, Deshazer M, Smith KDB, Ananta JS, Wilson LJ, Pautler RG. Assessing transneuronal dysfunction utilizing manganese-enhanced MRI (MEMRI). Magn Reson Med 2008; 60:169-75. [PMID: 18581360 DOI: 10.1002/mrm.21648] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In this study we utilized manganese-enhanced MRI (MEMRI) to evaluate the in vivo transneuronal efficiency of manganese ion (Mn(2+)) movement as a means to assess overall changes in neuronal function. We designated this extension the manganese transfer index (MTI) value. To evaluate the MTI value as an index of transneuronal physiology we examined both pharmacological agents and different mouse models of neuronal dysfunction. We found that treatment with isoflurane, which attenuates synaptic vesicle release, or memantine, which attenuates postsynaptic uptake of Ca(2+) as well as Mn(2+), resulted in a decrease in the MTI value. Furthermore, we evaluated if changes in the MTI value can be detected in three knockout mice with altered brain function accompanied either with or without neurodegeneration. Our data demonstrate that the MTI values either decreased or increased in response to different functional as well as anatomical changes. These results demonstrate the potential utility of the MTI value as an in vivo index for the detection of changes in neuronal function in animal models of human disease.
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Affiliation(s)
- Faridis Serrano
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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20
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Gassanov N, Er F, Zagidullin N, Jankowski M, Gutkowska J, Hoppe UC. Retinoid acid-induced effects on atrial and pacemaker cell differentiation and expression of cardiac ion channels. Differentiation 2008; 76:971-80. [DOI: 10.1111/j.1432-0436.2008.00283.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Xiao PJ, Hu L, Li J, Lin W, Chen X, Xu P. NSSR1 is regulated in testes development and cryptorchidism and promotes the exon 5-included splicing of CREB transcripts. Mol Reprod Dev 2007; 74:1363-72. [PMID: 17427975 DOI: 10.1002/mrd.20719] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Neural salient serine/arginine rich protein 1 (NSSR1, alternatively SRp38) is a newly identified splicing factor that is highly expressed in neural and reproductive tissues. We showed that the expression of testicular NSSR1 increased significantly during mouse testes development. NSSR1 was mainly expressed in germ cells, but barely detected in Sertoli cells. Testicular NSSR1 was mostly phosphorylated and cytosolic in germ cells. In comparison, pituitary NSSR1 was mostly dephosphorylated and nuclear. In the cryptorchid testes, the dephosphorylated NSSR1 was significantly increased. RT-PCR analysis demonstrated that the alternative splicing of CREB and CREM genes was altered in the cryptorchid testes. In addition, CREB transcripts were associated with NSSR1 either in testes tissues or cultured GC-1 cells. Moreover, the studies with NSSR1 over-expression or silence demonstrated that NSSR1 promoted the exon 5 inclusion of CREB, indicating that NSSR1 is a new factor that regulates the alternative exon 5 inclusion of CREB transcripts. The findings for the first time provide the evidence indicating the potential importance of NSSR1 in testes development, spermatogenesis and cryptorchidism.
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Affiliation(s)
- Ping-Jie Xiao
- Laboratory of Genomic Physiology and State Key Laboratory of Medical Neurobiology, School of Life Sciences and Shanghai Medical College, Fudan University, Shanghai, China
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22
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Ni MM, Luo Y, Liu J, Liao DQ, Tang YD. FMRFamide modulates outward potassium currents in mouse olfactory sensory neurons. Clin Exp Pharmacol Physiol 2007; 35:563-7. [PMID: 18067588 DOI: 10.1111/j.1440-1681.2007.04840.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
1. The olfactory system can detect the presence of low concentrations of odourant molecules and discriminate even slight differences among molecules with a very similar chemical structure. The detection and discrimination of odourants are correlated with the electrophysiology of the olfactory sensory neurons. To get a better understanding of the molecular mechanisms of olfactory transduction, it is therefore of considerable importance to obtain electrophysiological recordings of olfactory sensory neurons. FMRFamide (Phe-Met-Arg-Phe-NH(2)), secreted from the nerve terminals of the nasal cavity, has been suggested to act as a neurotransmitter or neuromodulator, playing an important role in modulating the activity of olfactory receptor neurons. Its effects on voltage-dependent potassium currents in the mouse olfactory sensory neurons were investigated in the present study using the whole-cell patch-clamp technique. 2. Olfactory sensory neurons were isolated from the Kunming Mouse (KM) mouse olfactory epithelium. Different protocols were applied to obtain delayed-rectifier potassium current (I(K)) and fast transient potassium current (I(A)). The effects of FMRFamide on the outward potassium currents, including I(K) and I(A), in mouse olfactory sensory neurons were investigated. 3. We found that FMRFamide (5 micromol/L) increased the magnitude of I(K). However no effect on I(A) was observed. The activation dynamics of both currents were not changed by FMRFamide. 4. In conclusion, FMRFamide may play a role in the modulation of peripheral olfactory signals by regulating I(K). This modulation may shorten the phase of the fast repolarization of the action potential in mouse olfactory sensory neurons and increase the excitability of the neuronal membrane.
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Affiliation(s)
- Mao-Mei Ni
- Department of Otorhinolaryngology, West China Hospital, Sichuian University, Chengdu, China
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