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Salamanca G, Tagliavia C, Grandis A, Graïc JM, Cozzi B, Bombardi C. Distribution of vasoactive intestinal peptide (VIP) immunoreactivity in the rat pallial and subpallial amygdala and colocalization with γ-aminobutyric acid (GABA). Anat Rec (Hoboken) 2024; 307:2891-2911. [PMID: 38263752 DOI: 10.1002/ar.25390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/25/2024]
Abstract
The amygdaloid complex, also known as the amygdala, is a heterogeneous group of distinct nuclear and cortical pallial and subpallial structures. The amygdala plays an important role in several complex functions including emotional behavior and learning. The expression of calcium-binding proteins and peptides in GABAergic neurons located in the pallial and subpallial amygdala is not uniform and is sometimes restricted to specific groups of cells. Vasoactive intestinal polypeptide (VIP) is present in specific subpopulations of GABAergic cells in the amygdala. VIP immunoreactivity has been observed in somatodendritic and axonal profiles of the rat basolateral and central amygdala. However, a comprehensive analysis of the distribution of VIP immunoreactivity in the various pallial and subpallial structures is currently lacking. The present study used immunohistochemical and morphometric techniques to analyze the distribution and the neuronal localization of VIP immunoreactivity in the rat pallial and subpallial amygdala. In the pallial amygdala, VIP-IR neurons are local inhibitory interneurons that presumably directly and indirectly regulate the activity of excitatory pyramidal neurons. In the subpallial amygdala, VIP immunoreactivity is expressed in several inhibitory cell types, presumably acting as projection or local interneurons. The distribution of VIP immunoreactivity is non-homogeneous throughout the different areas of the amygdaloid complex, suggesting a distinct influence of this neuropeptide on local neuronal circuits and, consequently, on the cognitive, emotional, behavioral and endocrine activities mediated by the amygdala.
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Affiliation(s)
- G Salamanca
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - C Tagliavia
- Department of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - A Grandis
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - J M Graïc
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - B Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - C Bombardi
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
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2
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Brockway DF, Crowley NA. Emerging pharmacological targets for alcohol use disorder. Alcohol 2024:S0741-8329(24)00101-0. [PMID: 39069210 DOI: 10.1016/j.alcohol.2024.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/27/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Alcohol Use Disorder (AUD) remains a challenging condition with limited effective treatment options; however new technology in drug delivery and advancements in pharmacology have paved the way for discovery of novel therapeutic targets. This review explores emerging pharmacological targets that offer new options for the management of AUD, focusing on the potential of somatostatin (SST), vasoactive intestinal peptide (VIP), glucagon-like peptide-1 (GLP-1), nociceptin (NOP), and neuropeptide S (NPS). These targets have been selected based on recent advancements in preclinical and clinical research, which suggest their significant roles in modulating alcohol consumption and related behaviors. SST dampens cortical circuits, and targeting both the SST neurons and the SST peptide itself presents promise for treating AUD and various related comorbidities. VIP neurons are modulated by alcohol and targeting the VIP system presents an unexplored avenue for addressing alcohol exposure at various stages of development. GLP-1 interacts with the dopaminergic reward system and reduces alcohol intake. Nociceptin modulates mesolimbic circuitry and agonism and antagonism of nociceptin receptor offers a complex but promising approach to reducing alcohol consumption. NPS stands out for its anxiolytic-like effects, particularly relevant for the anxiety associated with AUD. This review aims to synthesize the current understanding of these targets, highlighting their potential in developing more effective and personalized AUD therapies, and underscores the importance of continued research in identifying and validating novel targets for treatment of AUD and comorbid conditions.
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Affiliation(s)
- Dakota F Brockway
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
| | - Nicole A Crowley
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, USA; Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
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3
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Silveira MA, Herrera YN, Beebe NL, Schofield BR, Roberts MT. Lineage-tracing reveals an expanded population of NPY neurons in the inferior colliculus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.587042. [PMID: 38585909 PMCID: PMC10996674 DOI: 10.1101/2024.03.27.587042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Growing evidence suggests that neuropeptide signaling shapes auditory computations. We previously showed that neuropeptide Y (NPY) is expressed in the inferior colliculus (IC) by a population of GABAergic stellate neurons and that NPY regulates the strength of local excitatory circuits in the IC. NPY neurons were initially characterized using the NPY-hrGFP reporter mouse, in which hrGFP expression indicates NPY expression at the time of assay, i.e., an expression-tracking approach. However, studies in other brain regions have shown that NPY expression can vary based on a range of factors, suggesting that the NPY-hrGFP mouse might miss NPY neurons not expressing NPY proximal to the experiment date. Here, we hypothesized that neurons with the ability to express NPY represent a larger population of IC GABAergic neurons than previously reported. To test this hypothesis, we used a lineage-tracing approach to irreversibly tag neurons that expressed NPY at any point prior to the experiment date. We then compared the physiological and anatomical features of neurons labeled with this lineage-tracing approach to our prior data set, revealing a larger population of NPY neurons than previously found. In addition, we used optogenetics to test the local connectivity of NPY neurons and found that NPY neurons routinely provide inhibitory synaptic input to other neurons in the ipsilateral IC. Together, our data expand the definition of NPY neurons in the IC, suggest that NPY expression might be dynamically regulated in the IC, and provide functional evidence that NPY neurons form local inhibitory circuits in the IC.
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Affiliation(s)
- Marina A. Silveira
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan
- Department of Neuroscience, Development and Regenerative Biology, The University of Texas at San Antonio, San Antonio, Texas
| | - Yoani N. Herrera
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan
| | - Nichole L. Beebe
- University Hospitals Hearing Research Center at NEOMED, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Brett R. Schofield
- University Hospitals Hearing Research Center at NEOMED, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Michael T. Roberts
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
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4
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Beebe NL, Silveira MA, Goyer D, Noftz WA, Roberts MT, Schofield BR. Neurotransmitter phenotype and axonal projection patterns of VIP-expressing neurons in the inferior colliculus. J Chem Neuroanat 2022; 126:102189. [PMID: 36375740 PMCID: PMC9772258 DOI: 10.1016/j.jchemneu.2022.102189] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/09/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
Neurons in the inferior colliculus (IC), the midbrain hub of the central auditory pathway, send ascending and descending projections to other auditory brain regions, as well as projections to other sensory and non-sensory brain regions. However, the axonal projection patterns of individual classes of IC neurons remain largely unknown. Vasoactive intestinal polypeptide (VIP) is a neuropeptide expressed by subsets of neurons in many brain regions. We recently identified a class of IC stellate neurons that we called VIP neurons because they are labeled by tdTomato (tdT) expression in VIP-IRES-Cre x Ai14 mice. Here, using fluorescence in situ hybridization, we found that tdT+ neurons in VIP-IRES-Cre x Ai14 mice express Vglut2, a marker of glutamatergic neurons, and VIP, suggesting that VIP neurons use both glutamatergic and VIPergic signaling to influence their postsynaptic targets. Next, using viral transfections with a Cre-dependent eGFP construct, we labeled the axonal projections of VIP neurons. As a group, VIP neurons project intrinsically, within the ipsilateral and contralateral IC, and extrinsically to all the major targets of the IC. Within the auditory system, VIP neurons sent axons and formed axonal boutons in higher centers, including the medial geniculate nucleus and the nucleus of the brachium of the IC. Less dense projections terminated in lower centers, including the nuclei of the lateral lemniscus, superior olivary complex, and dorsal cochlear nucleus. VIP neurons also project to several non-auditory brain regions, including the superior colliculus, periaqueductal gray, and cuneiform nucleus. The diversity of VIP projections compared to the homogeneity of VIP neuron intrinsic properties suggests that VIP neurons play a conserved role at the microcircuit level, likely involving neuromodulation through glutamatergic and VIPergic signaling, but support diverse functions at the systems level through their participation in different projection pathways.
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Affiliation(s)
- Nichole L Beebe
- Hearing Research Group, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA.
| | - Marina A Silveira
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA.
| | - David Goyer
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA.
| | - William A Noftz
- Hearing Research Group, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA.
| | - Michael T Roberts
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
| | - Brett R Schofield
- Hearing Research Group, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA.
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Janković SM, Đešević M. Advancements in neuroactive peptides in seizures. Expert Rev Neurother 2022; 22:129-143. [DOI: 10.1080/14737175.2022.2031983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Slobodan M. Janković
- - University of Kragujevac, Faculty of Medical Sciences, Kragujevac, Serbia
- University Clinical Center, Kragujevac, Serbia
| | - Miralem Đešević
- - Private Policlinic Center Eurofarm Sarajevo, Cardiology Department, Sarajevo, Bosnia and Herzegovina
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Korkmaz OT, Arkan S, Öncü-Kaya EM, Ateş N, Tunçel N. Vasoactive intestinal peptide (VIP) conducts the neuronal activity during absence seizures: GABA seems to be the main mediator of VIP. Neurosci Lett 2021; 765:136268. [PMID: 34571088 DOI: 10.1016/j.neulet.2021.136268] [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: 02/13/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/27/2022]
Abstract
Absence epilepsy is classified as a childhood generalized epilepsy syndrome with distinctive electroencephalographic patterns. The Wistar Albino Glaxo originating from Rijswijk (WAG/Rij) strain is a very well validated animal model of absence epilepsy that also shows behavioral deficits. In addition to the gastrointestinal system, VIP is highly expressed throughout numerous brain regions, and it plays crucial roles as a neurotransmitter and as a neuromodulatory, neurotrophic and neuroprotective factor in both the central and peripheral nervous systems. In this study, adult WAG/Rij rats were divided into two groups (n = 10): a group that was administered VIP (25 ng/kg i.p.) every 2 days for 15 days and an age-matched control group that was administered physiological saline. Electrical brain activity and behavior (depressive- like behavior, learning and memory and anxiety) were investigated in both groups. In addition, the extracellular concentrations of GABA and glutamate and the GABA/glutamate ratio were measured by high-performance liquid chromatography in microdialysate samples collected from the somatosensorial cortex of WAG/Rij rats. Our results demonstrated that VIP treatment significantly suppressed the total duration and number of spike wave discharges in WAG/Rij rats. However, VIP had no significant effect on behavior. VIP increased the extracellular concentration of GABA and the GABA/glutamate ratio in the somatosensory cortex. In conclusion, VIP has suppressive effects on absence seizures, possibly by increasing the GABA concentration and inducing the transformation of glutamate to GABA in the somatosensory cortex of WAG/Rij rats.
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Affiliation(s)
- Orhan Tansel Korkmaz
- Department of Physiology, Faculty of Medicine, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey.
| | - Sertan Arkan
- Department of Physiology, Medical Faculty, Kocaeli University, 41380, Kocaeli, Turkey
| | - Elif Mine Öncü-Kaya
- Department of Chemistry, Science Faculty, Eskisehir Technical University, 26470 Eskisehir, Turkey
| | - Nurbay Ateş
- Department of Physiology, Medical Faculty, Kocaeli University, 41380, Kocaeli, Turkey
| | - Neşe Tunçel
- Department of Physiology, Faculty of Medicine, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey
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Popescu IR, Le KQ, Ducote AL, Li JE, Leland AE, Mostany R. Increased intrinsic excitability and decreased synaptic inhibition in aged somatosensory cortex pyramidal neurons. Neurobiol Aging 2020; 98:88-98. [PMID: 33249377 DOI: 10.1016/j.neurobiolaging.2020.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/02/2020] [Accepted: 10/08/2020] [Indexed: 10/23/2022]
Abstract
Sensorimotor performance declines during advanced age, partially due to deficits in somatosensory acuity. Cortical receptive field expansion contributes to somatosensory deficits, suggesting increased excitability or decreased inhibition in primary somatosensory cortex (S1) pyramidal neurons. To ascertain changes in excitability and inhibition, we measured both properties in neurons from vibrissal S1 in brain slices from young and aged mice. Because adapting and non-adapting neurons-the principal pyramidal types in layer 5 (L5)-differ in intrinsic properties and inhibitory inputs, we determined age-dependent changes according to neuron type. We found an age-dependent increase in intrinsic excitability in adapting neurons, caused by a decrease in action potential threshold. Surprisingly, in non-adapting neurons we found both an increase in excitability caused by increased input resistance, and a decrease in synaptic inhibition. Spike frequency adaptation, already small in non-adapting neurons, was further reduced by aging, whereas sag, a manifestation of Ih, was increased. Therefore, aging caused both decreased inhibition and increased intrinsic excitability, but these effects were specific to pyramidal neuron type.
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Affiliation(s)
- Ion R Popescu
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA, USA.
| | - Kathy Q Le
- Tulane Brain Institute, Tulane University, New Orleans, LA, USA
| | - Alexis L Ducote
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA, USA; Tulane Brain Institute, Tulane University, New Orleans, LA, USA
| | - Jennifer E Li
- Tulane Brain Institute, Tulane University, New Orleans, LA, USA
| | | | - Ricardo Mostany
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA, USA; Tulane Brain Institute, Tulane University, New Orleans, LA, USA
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8
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Abstract
Sleep spindles are burstlike signals in the electroencephalogram (EEG) of the sleeping mammalian brain and electrical surface correlates of neuronal oscillations in thalamus. As one of the most inheritable sleep EEG signatures, sleep spindles probably reflect the strength and malleability of thalamocortical circuits that underlie individual cognitive profiles. We review the characteristics, organization, regulation, and origins of sleep spindles and their implication in non-rapid-eye-movement sleep (NREMS) and its functions, focusing on human and rodent. Spatially, sleep spindle-related neuronal activity appears on scales ranging from small thalamic circuits to functional cortical areas, and generates a cortical state favoring intracortical plasticity while limiting cortical output. Temporally, sleep spindles are discrete events, part of a continuous power band, and elements grouped on an infraslow time scale over which NREMS alternates between continuity and fragility. We synthesize diverse and seemingly unlinked functions of sleep spindles for sleep architecture, sensory processing, synaptic plasticity, memory formation, and cognitive abilities into a unifying sleep spindle concept, according to which sleep spindles 1) generate neural conditions of large-scale functional connectivity and plasticity that outlast their appearance as discrete EEG events, 2) appear preferentially in thalamic circuits engaged in learning and attention-based experience during wakefulness, and 3) enable a selective reactivation and routing of wake-instated neuronal traces between brain areas such as hippocampus and cortex. Their fine spatiotemporal organization reflects NREMS as a physiological state coordinated over brain and body and may indicate, if not anticipate and ultimately differentiate, pathologies in sleep and neurodevelopmental, -degenerative, and -psychiatric conditions.
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Affiliation(s)
- Laura M J Fernandez
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Anita Lüthi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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Chevée M, Robertson JDJ, Cannon GH, Brown SP, Goff LA. Variation in Activity State, Axonal Projection, and Position Define the Transcriptional Identity of Individual Neocortical Projection Neurons. Cell Rep 2019; 22:441-455. [PMID: 29320739 DOI: 10.1016/j.celrep.2017.12.046] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/17/2017] [Accepted: 12/12/2017] [Indexed: 12/31/2022] Open
Abstract
Single-cell RNA sequencing has generated catalogs of transcriptionally defined neuronal subtypes of the brain. However, the cellular processes that contribute to neuronal subtype specification and transcriptional heterogeneity remain unclear. By comparing the gene expression profiles of single layer 6 corticothalamic neurons in somatosensory cortex, we show that transcriptional subtypes primarily reflect axonal projection pattern, laminar position within the cortex, and neuronal activity state. Pseudotemporal ordering of 1,023 cellular responses to sensory manipulation demonstrates that changes in expression of activity-induced genes both reinforced cell-type identity and contributed to increased transcriptional heterogeneity within each cell type. This is due to cell-type biased choices of transcriptional states following manipulation of neuronal activity. These results reveal that axonal projection pattern, laminar position, and activity state define significant axes of variation that contribute both to the transcriptional identity of individual neurons and to the transcriptional heterogeneity within each neuronal subtype.
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Affiliation(s)
- Maxime Chevée
- Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Johanna De Jong Robertson
- Human Genetics Training Program, McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gabrielle Heather Cannon
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Solange Pezon Brown
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Loyal Andrew Goff
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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10
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Fomicheva A, Zhou C, Sun QQ, Gomelsky M. Engineering Adenylate Cyclase Activated by Near-Infrared Window Light for Mammalian Optogenetic Applications. ACS Synth Biol 2019; 8:1314-1324. [PMID: 31145854 DOI: 10.1021/acssynbio.8b00528] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Light in the near-infrared optical window (NIRW) penetrates deep through mammalian tissues, including the skull and brain tissue. Here we engineered an adenylate cyclase (AC) activated by NIRW light (NIRW-AC) and suitable for mammalian applications. To accomplish this goal, we constructed fusions of several bacteriophytochrome photosensory and bacterial AC modules using guidelines for designing chimeric homodimeric bacteriophytochromes. One engineered NIRW-AC, designated IlaM5, has significantly higher activity at 37 °C, is better expressed in mammalian cells, and can mediate cAMP-dependent photoactivation of gene expression in mammalian cells, in favorable contrast to the NIRW-ACs engineered earlier. The ilaM5 gene expressed from an AAV vector was delivered into the ventral basal thalamus region of the mouse brain, resulting in the light-controlled suppression of the cAMP-dependent wave pattern of the sleeping brain known as spindle oscillations. Reversible spindle oscillation suppression was observed in sleeping mice exposed to light from an external light source. This study confirms the robustness of principles of homodimeric bacteriophytochrome engineering, describes a NIRW-AC suitable for mammalian optogenetic applications, and demonstrates the feasibility of controlling brain activity via NIRW-ACs using transcranial irradiation.
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Affiliation(s)
- Anastasia Fomicheva
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Chen Zhou
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Mark Gomelsky
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, United States
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11
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Chang X, Wang J, Jiang H, Shi L, Xie J. Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: An Emerging Role in Neurodegenerative Diseases. Front Mol Neurosci 2019; 12:141. [PMID: 31231190 PMCID: PMC6560157 DOI: 10.3389/fnmol.2019.00141] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 05/13/2019] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and spinal muscular atrophy (SMA) are chronic, progressive, and age-associated neurological disorders characterized by neuronal deterioration in specific brain regions. Although the specific pathological mechanisms underlying these disorders have remained elusive, ion channel dysfunction has become increasingly accepted as a potential mechanism for neurodegenerative diseases. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are encoded by the HCN1-4 gene family and conduct the hyperpolarization-activated current (I h). These channels play important roles in modulating cellular excitability, rhythmic activity, dendritic integration, and synaptic transmission. In the present review, we first provide a comprehensive picture of the role of HCN channels in PD by summarizing their role in the regulation of neuronal activity in PD-related brain regions. Dysfunction of I h may participate in 1-methyl-4-phenylpyridinium (MPP+)-induced toxicity and represent a pathogenic mechanism in PD. Given current reports of the critical role of HCN channels in neuroinflammation and depression, we also discussed the putative contribution of HCN channels in inflammatory processes and non-motor symptoms in PD. In the second section, we summarize how HCN channels regulate the formation of β-amyloid peptide in AD and the role of these channels in learning and memory. Finally, we briefly discuss the effects of HCN channels in ALS and SMA based on existing discoveries.
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Affiliation(s)
- Xiaoli Chang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China
- Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Jun Wang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China
- Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Hong Jiang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China
- Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Limin Shi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China
- Institute of Brain Science and Disease, Qingdao University, Qingdao, China
| | - Junxia Xie
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China
- Institute of Brain Science and Disease, Qingdao University, Qingdao, China
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12
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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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13
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Goyer D, Silveira MA, George AP, Beebe NL, Edelbrock RM, Malinski PT, Schofield BR, Roberts MT. A novel class of inferior colliculus principal neurons labeled in vasoactive intestinal peptide-Cre mice. eLife 2019; 8:43770. [PMID: 30998185 PMCID: PMC6516826 DOI: 10.7554/elife.43770] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 04/17/2019] [Indexed: 12/17/2022] Open
Abstract
Located in the midbrain, the inferior colliculus (IC) is the hub of the central auditory system. Although the IC plays important roles in speech processing, sound localization, and other auditory computations, the organization of the IC microcircuitry remains largely unknown. Using a multifaceted approach in mice, we have identified vasoactive intestinal peptide (VIP) neurons as a novel class of IC principal neurons. VIP neurons are glutamatergic stellate cells with sustained firing patterns. Their extensive axons project to long-range targets including the auditory thalamus, auditory brainstem, superior colliculus, and periaqueductal gray. Using optogenetic circuit mapping, we found that VIP neurons integrate input from the contralateral IC and the dorsal cochlear nucleus. The dorsal cochlear nucleus also drove feedforward inhibition to VIP neurons, indicating that inhibitory circuits within the IC shape the temporal integration of ascending inputs. Thus, VIP neurons are well-positioned to influence auditory computations in a number of brain regions.
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Affiliation(s)
- David Goyer
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, United States
| | - Marina A Silveira
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, United States
| | - Alexander P George
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, United States
| | - Nichole L Beebe
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, United States
| | - Ryan M Edelbrock
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, United States
| | - Peter T Malinski
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, United States
| | - Brett R Schofield
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, United States
| | - Michael T Roberts
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, United States
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14
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Ma S, Smith CM, Blasiak A, Gundlach AL. Distribution, physiology and pharmacology of relaxin-3/RXFP3 systems in brain. Br J Pharmacol 2016; 174:1034-1048. [PMID: 27774604 DOI: 10.1111/bph.13659] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 01/29/2023] Open
Abstract
Relaxin-3 is a member of a superfamily of structurally-related peptides that includes relaxin and insulin-like peptide hormones. Soon after the discovery of the relaxin-3 gene, relaxin-3 was identified as an abundant neuropeptide in brain with a distinctive topographical distribution within a small number of GABAergic neuron populations that is well conserved across species. Relaxin-3 is thought to exert its biological actions through a single class-A GPCR - relaxin-family peptide receptor 3 (RXFP3). Class-A comprises GPCRs for relaxin-3 and insulin-like peptide-5 and other peptides such as orexin and the monoamine transmitters. The RXFP3 receptor is selectively activated by relaxin-3, whereas insulin-like peptide-5 is the cognate ligand for the related RXFP4 receptor. Anatomical and pharmacological evidence obtained over the last decade supports a function of relaxin-3/RXFP3 systems in modulating responses to stress, anxiety-related and motivated behaviours, circadian rhythms, and learning and memory. Electrophysiological studies have identified the ability of RXFP3 agonists to directly hyperpolarise thalamic neurons in vitro, but there are no reports of direct cell signalling effects in vivo. This article provides an overview of earlier studies and highlights more recent research that implicates relaxin-3/RXFP3 neural network signalling in the integration of arousal, motivation, emotion and related cognition, and that has begun to identify the associated neural substrates and mechanisms. Future research directions to better elucidate the connectivity and function of different relaxin-3 neuron populations and their RXFP3-positive target neurons in major experimental species and humans are also identified. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Craig M Smith
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Victoria, Australia
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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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16
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Lezak KR, Roelke E, Harris OM, Choi I, Edwards S, Gick N, Cocchiaro G, Missig G, Roman CW, Braas KM, Toufexis DJ, May V, Hammack SE. Pituitary adenylate cyclase-activating polypeptide (PACAP) in the bed nucleus of the stria terminalis (BNST) increases corticosterone in male and female rats. Psychoneuroendocrinology 2014; 45:11-20. [PMID: 24845172 PMCID: PMC4050443 DOI: 10.1016/j.psyneuen.2014.03.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/13/2014] [Accepted: 03/17/2014] [Indexed: 11/17/2022]
Abstract
Single nucleotide polymorphisms (SNP) in the genes for pituitary adenylate cyclase-activating polypeptide (PACAP) and the PAC1 receptor have been associated with several psychiatric disorders whose etiology has been associated with stressor exposure and/or dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. In rats, exposure to repeated variate stress has been shown to increase PACAP and its cognate PAC1 receptor expression in the bed nucleus of the stria terminalis (BNST), a brain region implicated in anxiety and depression-related behaviors as well as the regulation of HPA axis activity. We have argued that changes in BNST PACAP signaling may mediate the changes in emotional behavior and dysregulation of the HPA axis associated with anxiety and mood disorders. The current set of studies was designed to determine whether BNST PACAP infusion leads to activation of the HPA axis as determined by increases in plasma corticosterone. We observed an increase in plasma corticosterone levels 30min following BNST PACAP38 infusion in male and female rats, which was independent of estradiol (E2) treatment in females, and we found that plasma corticosterone levels were increased at both 30min and 60min, but returned to baseline levels 4h following the highest dose. PACAP38 infusion into the lateral ventricles immediately above the BNST did not alter plasma corticosterone level, and the increased plasma corticosterone following BNST PACAP was not blocked by BNST corticotropin releasing hormone (CRH) receptor antagonism. These results support others suggesting that BNST PACAP plays a key role in regulating stress responses.
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Affiliation(s)
- K R Lezak
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States
| | - E Roelke
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States
| | - O M Harris
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States
| | - I Choi
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States; Department of Neurological Sciences, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, United States
| | - S Edwards
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States; Department of Neurological Sciences, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, United States
| | - N Gick
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States; Department of Neurological Sciences, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, United States
| | - G Cocchiaro
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States
| | - G Missig
- Department of Neurological Sciences, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, United States
| | - C W Roman
- Department of Neurological Sciences, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, United States
| | - K M Braas
- Department of Neurological Sciences, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, United States
| | - D J Toufexis
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States
| | - V May
- Department of Neurological Sciences, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, United States
| | - S E Hammack
- Department of Psychology, University of Vermont, 2 Colchester Avenue, Burlington, VT 05405, United States.
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Ma J, Yao XH, Fu Y, Yu YC. Development of Layer 1 Neurons in the Mouse Neocortex. Cereb Cortex 2014; 24:2604-18. [DOI: 10.1093/cercor/bht114] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Campos-Salinas J, Cavazzuti A, O'Valle F, Forte-Lago I, Caro M, Beverley SM, Delgado M, Gonzalez-Rey E. Therapeutic efficacy of stable analogues of vasoactive intestinal peptide against pathogens. J Biol Chem 2014; 289:14583-99. [PMID: 24706753 DOI: 10.1074/jbc.m114.560573] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Vasoactive intestinal peptide (VIP) is an anti-inflammatory neuropeptide recently identified as a potential antimicrobial peptide. To overcome the metabolic limitations of VIP, we modified the native peptide sequence and generated two stable synthetic analogues (VIP51 and VIP51(6-30)) with better antimicrobial profiles. Herein we investigate the effects of both VIP analogues on cell viability, membrane integrity, and ultrastructure of various bacterial strains and Leishmania species. We found that the two VIP derivatives kill various non-pathogenic and pathogenic Gram-positive and Gram-negative bacteria as well as the parasite Leishmania major through a mechanism that depends on the interaction with certain components of the microbial surface, the formation of pores, and the disruption of the surface membrane. The cytotoxicity of the VIP derivatives is specific for pathogens, because they do not affect the viability of mammalian cells. Docking simulations indicate that the chemical changes made in the analogues are critical to increase their antimicrobial activities. Consequently, we found that the native VIP is less potent as an antibacterial and fails as a leishmanicidal. Noteworthy from a therapeutic point of view is that treatment with both derivatives increases the survival and reduces bacterial load and inflammation in mice with polymicrobial sepsis. Moreover, treatment with VIP51(6-30) is very effective at reducing lesion size and parasite burden in a model of cutaneous leishmaniasis. These results indicate that the VIP analogues emerge as attractive alternatives for treating drug-resistant infectious diseases and provide key insights into a rational design of novel agents against these pathogens.
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Affiliation(s)
| | - Antonio Cavazzuti
- From the Institute of Parasitology and Biomedicine, CSIC, Granada 18016, Spain
| | - Francisco O'Valle
- the Department of Pathological Anatomy, Medical School of Granada, Granada 18012, Spain
| | - Irene Forte-Lago
- From the Institute of Parasitology and Biomedicine, CSIC, Granada 18016, Spain
| | - Marta Caro
- From the Institute of Parasitology and Biomedicine, CSIC, Granada 18016, Spain
| | - Stephen M Beverley
- the Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, and
| | - Mario Delgado
- From the Institute of Parasitology and Biomedicine, CSIC, Granada 18016, Spain
| | - Elena Gonzalez-Rey
- From the Institute of Parasitology and Biomedicine, CSIC, Granada 18016, Spain, the Department of Biochemistry and Molecular Biology, Medical School of Seville, Seville 41009, Spain
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He C, Chen F, Li B, Hu Z. Neurophysiology of HCN channels: From cellular functions to multiple regulations. Prog Neurobiol 2014; 112:1-23. [DOI: 10.1016/j.pneurobio.2013.10.001] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 10/01/2013] [Accepted: 10/07/2013] [Indexed: 12/18/2022]
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20
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Zou YC, Liu LQ, Zhang MX. The expression of vasoactive intestinal polypeptide in visual cortex-17 in normal visual development and formation of anisometropic amblyopia. Semin Ophthalmol 2013; 29:59-65. [PMID: 23947335 DOI: 10.3109/08820538.2012.760620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AIMS To document the expression of vasoactive intestinal polypeptide (VIP) in the visual cortex-17 of kittens with anisometropic amblyopia, and to investigate the relationship between VIP and the development of the visual system. METHODS Sixteen normal kittens (4-wk of age) were randomly divided into two groups: control and amblyopic. Amblyopia was produced by atropinization of one eye in eight kittens. Four (2 normal and 2 amblyopia) kittens were sacrificed at weeks 3, 6, 9, or 12 post-treatment respectively. Expression of VIP-mRNA in the visual cortex-17 was detected through in-situ hybridization. Neurons in the visual cortex were visualized by transmission electron microscopy (TEM). The number of neurons was analyzed via light microscopy (LM). RESULTS VIP-mRNA expression was increased with age in control kittens but remained nearly static in age-matched anisometropic amblyopic kittens (p < 0.05). The number of VIP-positive cells of amblyopic kittens decreased dramatically when compared to normal age-matched kittens (p < 0.05). The total comparison between different positive ranks suggested a significant difference. The degree of expression between these two groups was significantly different. Ultrastructurally, in the control group, the nuclear membrane of most neurons was discernable and chromatin was evenly distributed within the nucleus. Abundant cytoplasm and tubular-shaped mitochondria were observed. These cells were also rich in Golgi bodies, ribosomes, and endoplasmic reticulum. In amblyopic kittens, nuclei of most neurons were aggregated, the number of ribosomes and Golgi bodies was reduced, mitochondria were swollen, and mitochondrial cristae were shortened or even absent. The endoplasmic reticulum was distended and reduced in magnitude. CONCLUSIONS VIP appears to play an important role in visual development, and its mRNA expression is affected by visual experiences. Visual dysfunction may down-regulate the expression of VIP-mRNA by impairing the structure and function of the neurons in the visual cortex, finally leading to amblyopia.
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Affiliation(s)
- Yun-Chun Zou
- Department of Ophthalmology, West China Hospital, Sichuan University , Chengdu , China and
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21
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Kolaj M, Zhang L, Rønnekleiv OK, Renaud LP. Midline thalamic paraventricular nucleus neurons display diurnal variation in resting membrane potentials, conductances, and firing patterns in vitro. J Neurophysiol 2012; 107:1835-44. [PMID: 22219029 DOI: 10.1152/jn.00974.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons in the rodent midline thalamic paraventricular nucleus (PVT) receive inputs from brain stem and hypothalamic sites known to participate in sleep-wake and circadian rhythms. To evaluate possible diurnal changes in their excitability, we used patch-clamp techniques to record and examine the properties of neurons in anterior PVT (aPVT) in coronal rat brain slices prepared at zeitgeber time (ZT) 2-6 vs. ZT 14-18 and recorded at ZT 8.4 ± 0.2 (day) vs. ZT 21.2 ± 0.2 (night), the subjective quiet vs. aroused states, respectively. Compared with neurons recorded during the day, neurons from the night period were significantly more depolarized and exhibited a lower membrane conductance that in part reflected loss of a potassium-mediated conductance. Furthermore, these neurons were also significantly more active, with tonic and burst firing patterns. Neurons from each ZT period were assessed for amplitudes of two conductances known to contribute to bursting behavior, i.e., low-threshold-activated Ca(2+) currents (I(T)) and hyperpolarization-activated cation currents (I(h)). Data revealed that amplitudes of both I(T) and I(h) were significantly larger during the night period. In addition, biopsy samples from the night period revealed a significant increase in mRNA for Ca(v)3.1 and Ca(v)3.3 low-threshold Ca(2+) channel subtypes. Neurons recorded from the night period also displayed a comparative enhancement in spontaneous bursting at membrane potentials of approximately -60 mV and in burst firing consequent to hyperpolarization-induced low-threshold currents and depolarization-induced current pulses. These novel in vitro observations reveal that midline thalamic neurons undergo diurnal changes in their I(T), I(h), and undefined potassium conductances. The underlying mechanisms remain to be characterized.
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Affiliation(s)
- Miloslav Kolaj
- Neuroscience, Ottawa Hospital Research Institute, 725 Parkdale Ave., Ottawa, ON Canada K1Y 4E9
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22
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Du P, Lee CH, Choi JH, Yoo KY, Lee YL, Kang IJ, Hwang IK, Kim JD, Won MH. Pituitary adenylate cyclase-activating polypeptide-immunoreactive cells in the ageing gerbil hippocampus. Anat Histol Embryol 2011; 40:389-96. [PMID: 21545645 DOI: 10.1111/j.1439-0264.2011.01083.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study, we investigated age-related changes in pituitary adenylate cyclase-activating polypeptide (PACAP) immunoreactivity and its protein levels in the gerbil hippocampus at various ages using immunohistochemistry and western blot analysis. In the post-natal month 1 (PM 1) group, PACAP-immunoreactive cells were found in all hippocampal subregions. The number of PACAP-immunoreactive cells was decreased in the PM 3 group and was still more decreased in the PM 6 and 12 groups. Thereafter, in the PM 18 and 24 groups, PACAP-immunoreactive cells were significantly increased again. However, in the mossy fibre zone, PACAP immunostaining was very strong in the adult group, especially in the PM 6 group. In addition, PACAP protein level was highest at PM 6, showing a slight decrease at PM 24. These results indicate that PACAP-immunoreactive cells are lowest in the adult stage and highest in the aged stage. However, PACAP immunoreactivity in the mossy fibre zone and PACAP protein level in the hippocampus are highest in the adult stage.
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Affiliation(s)
- P Du
- Department of Physiology, College of Medicine, and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon, South Korea
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Lewis AS, Chetkovich DM. HCN channels in behavior and neurological disease: too hyper or not active enough? Mol Cell Neurosci 2010; 46:357-67. [PMID: 21130878 DOI: 10.1016/j.mcn.2010.11.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 11/11/2010] [Indexed: 02/08/2023] Open
Abstract
The roles of cells within the nervous system are based on their properties of excitability, which are in part governed by voltage-gated ion channels. HCN channels underlie the hyperpolarization-activated current, I(h), an important regulator of excitability and rhythmicity through control of basic membrane properties. I(h) is present in multiple neuronal types and regions of the central nervous system, and changes in I(h) alter cellular input-output properties and neuronal circuitry important for behavior such as learning and memory. Furthermore, the pathophysiology of neurological diseases of both the central and peripheral nervous system involves defects in excitability, rhythmicity, and signaling, and animal models of many of these disorders have implicated changes in HCN channels and I(h) as critical for pathogenesis. In this review, we focus on recent research elucidating the role of HCN channels and I(h) in behavior and disease. These studies have utilized knockout mice as well as animal models of disease to examine how I(h) may be important in regulating learning and memory, sleep, and consciousness, as well as how misregulation of I(h) may contribute to epilepsy, chronic pain, and other neurological disorders. This review will help guide future studies aimed at further understanding the function of this unique conductance in both health and disease of the mammalian brain.
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Affiliation(s)
- Alan S Lewis
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Hermes MLHJ, Kolaj M, Doroshenko P, Coderre E, Renaud LP. Effects of VPAC2 receptor activation on membrane excitability and GABAergic transmission in subparaventricular zone neurons targeted by suprachiasmatic nucleus. J Neurophysiol 2009; 102:1834-42. [PMID: 19571188 DOI: 10.1152/jn.91261.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The hypothalamic suprachiasmatic nucleus (SCN) harbors the master circadian pacemaker. SCN neurons produce the amino acid gamma-aminobutyric acid (GABA) and several peptide molecules for coordination and communication of their circadian rhythms. A subpopulation of SCN cells synthesizes vasoactive intestinal polypeptide (VIP) and provides a dense innervation of the subparaventricular zone (SPZ), an important CNS target of the circadian pacemaker. In this study, using patch-clamp recording techniques and rat brain slice preparations, the contribution of VIP to SCN efferent signaling to SPZ was evaluated by examining membrane responses of SPZ neurons to exogenous VIP receptor ligands. In approximately 50% of the SPZ neurons receiving monosynaptic GABAA receptor-mediated inputs from SCN, bath-applied VIP (0.5-1 microM) resulted in a membrane depolarization caused by tetrodotoxin-resistant inward currents reversing at approximately -23 mV. These data suggest the existence of postsynaptic receptors that activate a nonselective cationic conductance. In addition, a subset of SPZ neurons showed an increase in the amplitude of SCN-evoked GABAergic inhibitory postsynaptic currents (IPSCs) and a decrease in their paired-pulse ratios. This, together with an increase in frequency of spontaneous and miniature IPSCs, implies the presence of presynaptic receptors that facilitate GABA release from SCN and possibly other synaptic terminals. The effects occurred in separate neurons and could be mimicked by the selective VPAC2 receptor agonist BAY 55-9837 (0.2-0.5 microM) and partially blocked by the VIP receptor antagonist VIP(6-28) (5 microM). The results indicate that VIP acts via both post- and presynaptic VPAC2 receptors to differentially modulate SCN GABAergic signaling to distinct subpopulations of SPZ neurons.
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Affiliation(s)
- M L H J Hermes
- Neurosciences, Ottawa Hospital Research Institute and University of Ottawa, 725 Parkdale Avenue, Ottawa, Ontario, Canada K1Y 4E9
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Benagiano V, Flace P, Lorusso L, Rizzi A, Bosco L, Cagiano R, Ambrosi G. Vasoactive intestinal polypeptide immunoreactivity in the human cerebellum: qualitative and quantitative analyses. J Anat 2009; 215:256-66. [PMID: 19552726 DOI: 10.1111/j.1469-7580.2009.01110.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Although autoradiographic, reverse transcription-polymerase chain reaction and immunohistochemical studies have demonstrated receptors for vasoactive intestinal polypeptide (VIP) in the cerebellum of various species, immunohistochemistry has never shown immunoreactivity for VIP within cerebellar neuronal bodies and processes. The present study aimed to ascertain whether VIP immunoreactivity really does exist in the human cerebellum by making a systematic analysis of samples removed post-mortem from all of the cerebellar lobes. The study was carried out using light microscopy immunohistochemical techniques based on a set of four different antibodies (three polyclonal and one monoclonal) against VIP, carefully selected on the basis of control tests performed on human colon. All of the antibodies used showed VIP-immunoreactive neuronal bodies and processes distributed in the cerebellar cortex and subjacent white matter of all of the cerebellum lobes, having similar qualitative patterns of distribution. Immunoreactive neurons included subpopulations of the main neuron types of the cortex. Statistical analysis of the quantitative data on the VIP immunoreactivity revealed by the different antibodies in the different cerebellar lobes did not demonstrate any significant differences. In conclusion, using four different anti-VIP antibodies, the first evidence of VIP immunoreactivity is herein supplied in the human post-mortem cerebellum, with similar qualitative/quantitative patterns of distribution among the different cerebellum lobes. Owing to the function performed by VIP as a neurotransmitter/neuromodulator, it is a candidate for a role in intrinsic and extrinsic (projective) circuits of the cerebellum, in agreement with previous demonstrations of receptors for VIP in the cerebellar cortex and nuclei. As VIP signalling pathways are implicated in the regulation of cognitive and psychic functions, cerebral blood flow and metabolism, processes of histomorphogenesis, differentiation and outgrowth of nervous tissues, the results of this study could be applied to clinical neurology and psychiatry, opening new perspectives for the interpretation of neurodevelopment disorders and development of new therapeutic strategies in cerebellar diseases.
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Affiliation(s)
- Vincenzo Benagiano
- Dipartimento di Anatomia Umana e Istologia R. Amprino, University of Bari, 71124 Bari, Italy.
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Lee SH, Cox CL. Excitatory actions of peptide histidine isoleucine on thalamic relay neurons. Neuropharmacology 2008; 55:1329-39. [PMID: 18804119 DOI: 10.1016/j.neuropharm.2008.08.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 08/15/2008] [Accepted: 08/18/2008] [Indexed: 11/30/2022]
Abstract
Peptide histidine isoleucine (PHI) and vasoactive intestinal peptide (VIP) are neuropeptides synthesized from a common precursor, prepro-VIP, and share structural similarity and biological functions in many systems. Within the central nervous system and peripheral tissues, PHI and VIP have overlapping distribution. PHI-mediated functions are generally via activation of VIP receptors; however, the potency and affinity of PHI for VIP receptors are significantly lower than VIP. In addition, several studies suggest distinct PHI receptors that are independent of VIP receptors. PHI receptors have been cloned and characterized in fish, but their existence in mammals is still unknown. This study focuses on the functional role of PHI in the thalamus because of the localization of both PHI and VIP receptors in this brain region. Using extracellular multiple-unit recording techniques, we found that PHI strongly attenuated the slow intrathalamic rhythmic activity. Using intracellular recording techniques, we found that PHI selectively depolarized thalamic relay neurons via an enhancement of the hyperpolarization-activated mixed cation current, Ih. Further, the actions of PHI were occluded by VIP and dopamine, indicating these modulators converge onto a common mechanism. In contrast to previous work, we found that PHI was more potent than VIP in producing excitatory actions on thalamic neurons. We next used the transgenic mice lacking a specific VIP receptor, VPAC2, to identify its possible role in PHI-mediated actions in the thalamus. PHI depolarized all relay neurons tested from wild-type mice (VPAC2(+/+)); however, in knockout mice (VPAC2(-/-)), PHI produced no change in membrane potential in all neurons tested. Our findings indicate that excitatory actions of PHI are mediated by VPAC2 receptors, not by its own PHI receptors and the excitatory actions of PHI clearly attenuate intrathalamic rhythmic activities, and likely influence information transfer through thalamocortical circuits.
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Affiliation(s)
- Sang-Hun Lee
- Department of Molecular and Integrative Physiology, 2357 Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, MC-251, Urbana, IL 61801, United States
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Chaudhury D, Loh DH, Dragich JM, Hagopian A, Colwell CS. Select cognitive deficits in vasoactive intestinal peptide deficient mice. BMC Neurosci 2008; 9:63. [PMID: 18616823 PMCID: PMC2474849 DOI: 10.1186/1471-2202-9-63] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 07/10/2008] [Indexed: 12/03/2022] Open
Abstract
Background The neuropeptide vasoactive intestinal peptide (VIP) is widely distributed in the adult central nervous system where this peptide functions to regulate synaptic transmission and neural excitability. The expression of VIP and its receptors in brain regions implicated in learning and memory functions, including the hippocampus, cortex, and amygdala, raise the possibility that this peptide may function to modulate learned behaviors. Among other actions, the loss of VIP has a profound effect on circadian timing and may specifically influence the temporal regulation of learning and memory functions. Results In the present study, we utilized transgenic VIP-deficient mice and the contextual fear conditioning paradigm to explore the impact of the loss of this peptide on a learned behavior. We found that VIP-deficient mice exhibited normal shock-evoked freezing behavior and increases in corticosterone. Similarly, these mutant mice exhibited no deficits in the acquisition or recall of the fear-conditioned behavior when tested 24-hours after training. The VIP-deficient mice exhibited a significant reduction in recall when tested 48-hours or longer after training. Surprisingly, we found that the VIP-deficient mice continued to express circadian rhythms in the recall of the training even in those individual mice whose wheel running wheel activity was arrhythmic. One mechanistic explanation is suggested by the finding that daily rhythms in the expression of the clock gene Period2 continue in the hippocampus of VIP-deficient mice. Conclusion Together these data suggest that the neuropeptide VIP regulates the recall of at least one learned behavior but does not impact the circadian regulation of this behavior.
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Affiliation(s)
- Dipesh Chaudhury
- Department of Psychiatry and Biobehavioral Sciences, University of California - Los Angeles, 760 Westwood Plaza, Los Angeles, California 90024-1759, USA.
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28
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Christian CA, Moenter SM. Vasoactive intestinal polypeptide can excite gonadotropin-releasing hormone neurons in a manner dependent on estradiol and gated by time of day. Endocrinology 2008; 149:3130-6. [PMID: 18326000 PMCID: PMC2408801 DOI: 10.1210/en.2007-1098] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A surge of GnRH release signals the LH surge that triggers ovulation. The GnRH surge is dependent on a switch in estradiol feedback from negative to positive and, in rodents, a daily neural signal, likely from the suprachiasmatic nuclei. Vasoactive intestinal polypeptide (VIP) may be involved in suprachiasmatic nuclei-GnRH neuron communication. Here we assessed the effects of acute VIP (5 min treatment) on GnRH neuron function using targeted extracellular recordings of firing activity of GnRH neurons in brain slices. We examined the effect of VIP on firing rate at different times of day using an established ovariectomized, estradiol-treated (OVX+E) mouse model that exhibits daily LH surges timed to the late afternoon. Cells from OVX animals (no estradiol) did not respond to VIP, regardless of time of day. With estradiol, the effect of VIP on GnRH neurons was dependent on the time of recording. During negative feedback, OVX+E cells did not respond. VIP increased firing in cells recorded during surge onset, but this excitatory response was reduced at surge peak. Acute treatment of OVX+E cells during surge peak with a VIP receptor antagonist decreased GnRH neuron firing. This suggests endogenous VIP may both increase GnRH neuron firing during the surge and occlude response to exogenous VIP. These data provide functional evidence for VIP effects on GnRH neurons and indicate that both estradiol and time of day gate the GnRH neuron response to this peptide. VIP may provide an excitatory signal from the circadian clock that helps time the GnRH surge.
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Affiliation(s)
- Catherine A Christian
- Neuroscience Graduate Program, Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, USA
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29
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de Lecea L. Cortistatin--functions in the central nervous system. Mol Cell Endocrinol 2008; 286:88-95. [PMID: 18374474 DOI: 10.1016/j.mce.2007.12.014] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 11/29/2007] [Accepted: 12/19/2007] [Indexed: 11/22/2022]
Abstract
Cortistatin (CST) is a neuropeptide from the somatostatin (SRIF)/urotensin (UII) family named after its predominantly cortical expression and ability to depress cortical activity, which was discovered a decade ago. In vitro assays show CST is able to bind all five cloned somatostatin receptors and shares many pharmacological and functional properties with SRIF. However, distinct from SRIF, CST has been shown to induce slow-wave sleep, reduce locomotor activity, and activate cation selective currents not responsive to somatostatin. Different lines of evidence also indicate that CST, like SRIF, is involved in learning and memory processes. CST-14 may also function as an endogenous anti-convulsant. In addition to its role in cortical synchronization, CST-14 has emerged as an important mediator of immunity and inflammation. This review will cover some of the basic properties of CST in the brain, and will discuss new data on the role of CST in cortical activity.
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Affiliation(s)
- Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA 94304, USA.
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30
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Dávid C, Schleicher A, Zuschratter W, Staiger JF. The innervation of parvalbumin-containing interneurons by VIP-immunopositive interneurons in the primary somatosensory cortex of the adult rat. Eur J Neurosci 2007; 25:2329-40. [PMID: 17445231 DOI: 10.1111/j.1460-9568.2007.05496.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
gamma-Aminobutyric acid (GABA)ergic interneurons of neocortex consist of many subgroups with extremely heterogeneous morphological, physiological and molecular properties. To explore the putative effect of the vasoactive intestinal polypeptide-immunopositive (VIP +) neurons on neocortical circuitry, the number and distribution of VIP + boutons were analysed on somatodendritic domains of 272 parvalbumin immunopositive (PV +) 3D-reconstructed neurons. The synaptic nature of 91% of somatic and 76% of dendritic contacts was verified by electron microscopy. The target PV + neurons were separated in two significantly different groups by means of cluster analysis. The first group (Cluster 1, 26%) received on average five times more VIP + synapses than those of the second group. The second group (Cluster 2, 74%) contained cells that were poorly innervated by VIP + boutons or did not have either somatic or dendritic or any VIP innervation at all. The cells of Cluster 1 had a soma size and total dendritic length significantly smaller than that of Cluster 2, however, they received three times more dendritic synapses, which resulted in a five times higher VIP + synaptic density on dendrites. Our results showed that although most of the PV + cells are innervated by VIP + boutons at a varying degree, some 6% of PV + cells received no input from VIP + interneurons. This suggests a refined morphological basis to influence the majority of the PV + interneurons, which are very effectively controlling pyramidal cell firing. Together with metabolic and neuromodulatory effects of VIP, this would probably result in an enhanced responsiveness of the latter cell type to tactile stimuli.
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Affiliation(s)
- Csaba Dávid
- Albert-Ludwigs-University Freiburg, Institute of Anatomy and Cell Biology, Department of Neuroanatomy, D-79001 Freiburg, Germany.
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31
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Vosko AM, Schroeder A, Loh DH, Colwell CS. Vasoactive intestinal peptide and the mammalian circadian system. Gen Comp Endocrinol 2007; 152:165-75. [PMID: 17572414 PMCID: PMC1994114 DOI: 10.1016/j.ygcen.2007.04.018] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 04/17/2007] [Accepted: 04/19/2007] [Indexed: 11/25/2022]
Abstract
In mammals, the circadian oscillators that drive daily behavioral and endocrine rhythms are located in the hypothalamic suprachiasmatic nucleus (SCN). While the SCN is anatomically well-situated to receive and transmit temporal cues to the rest of the brain and periphery, there are many holes in our understanding of how this temporal regulation occurs. Unanswered questions include how cell autonomous circadian oscillations within the SCN remain synchronized to each other as well as communicate temporal information to downstream targets. In recent years, it has become clear that neuropeptides are critically involved in circadian timekeeping. One such neuropeptide, vasoactive intestinal peptide (VIP), defines a cell population within the SCN and is likely used as a signaling molecule by these neurons. Converging lines of evidence suggest that the loss of VIP or its receptor has a major influence on the ability of the SCN neurons to generate circadian oscillations as well as synchronize these cellular oscillations. VIP, acting through the VPAC(2) receptor, exerts these effects in the SCN by activating intracellular signaling pathways and, consequently, modulating synaptic transmission and intrinsic membrane currents. Anatomical evidence suggests that these VIP expressing neurons connect both directly and indirectly to endocrine and other output targets. Striking similarities exist between the role of VIP in mammals and the role of Pigment Dispersing Factor (PDF), a functionally related neuropeptide, in the Drosophila circadian system. Work in both mammals and insects suggests that further research into neuropeptide function is necessary to understand how circadian oscillators work as a coordinated system to impose a temporal structure on physiological processes within the organism.
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Affiliation(s)
- Andrew M Vosko
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience, University of California--Los Angeles, 760 Westwood Plaza, Los Angeles, CA 90024-1759, USA
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32
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Xu F, Tse FW, Tse A. Pituitary adenylate cyclase-activating polypeptide (PACAP) stimulates the oxygen sensing type I (glomus) cells of rat carotid bodies via reduction of a background TASK-like K+current. J Neurochem 2007; 101:1284-93. [PMID: 17498241 DOI: 10.1111/j.1471-4159.2007.04468.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP)-deficient mice are prone to sudden neonatal death and have reduced respiratory response to hypoxia. Here we found that PACAP-38 elevated cytosolic [Ca(2+)] ([Ca(2+)](i)) in the oxygen sensing type I cells but not the glial-like type II (sustentacular) cells of the rat carotid body. This action of PACAP could not be mimicked by vasoactive intestinal peptide but was abolished by PACAP 6-38, implicating the involvement of PAC(1) receptors. H89, a protein kinase A (PKA) inhibitor attenuated the PACAP response. Simultaneous measurement of membrane potential and [Ca(2+)](i) showed that the PACAP-mediated [Ca(2+)](i) rise was accompanied by depolarization and action potential firing. Ni(2+), a blocker of voltage-gated Ca(2+) channels (VGCC) or the removal of extracellular Ca(2+) reversibly inhibited the PACAP-mediated [Ca(2+)](i) rise. In the presence of tetraethylammonium (TEA) and 4-aminopyridine (4-AP), PACAP reduced a background K(+) current. Anandamide, a blocker of TWIK-related acid-sensitive K(+) (TASK)-like K(+) channel, occluded the inhibitory action of PACAP on K(+) current. We conclude that PACAP, acting via the PAC(1) receptors coupled PKA pathway inhibits a TASK-like K(+) current and causes depolarization and VGCC activation. This stimulatory action of PACAP in carotid type I cells can partly account for the role of PACAP in respiratory disorders.
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Affiliation(s)
- Fenglian Xu
- Department of Pharmacology and Center for Neurosciences, 9-70 Medical Science Building, University of Alberta, Edmonton, Alberta, Canada
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33
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Zhang C, Szabó G, Erdélyi F, Rose JD, Sun QQ. Novel interneuronal network in the mouse posterior piriform cortex. J Comp Neurol 2006; 499:1000-15. [PMID: 17072835 DOI: 10.1002/cne.21166] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The neural circuits of the piriform cortex mediate field potential oscillations and complex functions related to integrating odor cues with behavior, affective states, and multisensory processing. Previous anatomical studies have established major neural pathways linking the piriform cortex to other cortical and subcortical regions and major glutamatergic and GABAergic neuronal subtypes within the piriform circuits. However, the quantitative properties of diverse piriform interneurons are unknown. Using quantitative neural anatomical analysis and electrophysiological recording applied to a GAD65-EGFP transgenic mouse expressing GFP (green fluorescent protein) under the control of the GAD65 promoter, here we report a novel inhibitory network that is composed of neurons positive for GAD65-EGFP in the posterior piriform cortex (PPC). These interneurons had stereotyped dendritic and axonal properties that were distinct from basket cells or interneurons expressing various calcium-binding proteins (parvalbumin, calbindin, and calretinin) within the PPC. The GAD65-GFP neurons are GABAergic and outnumbered any other interneurons (expressing parvalbumin, calbindin, and calretinin) we studied. The firing pattern of these interneurons was highly homogenous and is similar to the regular-spiking nonpyramidal (RSNP) interneurons reported in primary sensory and other neocortical regions. Robust dye coupling among these interneurons and expression of connexin 36 suggested that they form electrically coupled networks. The predominant targets of descending axons of these interneurons were the dendrites of Layer III principal cells. Additionally, synapses were found on dendrites and somata of deep Layer II principal neurons and Layer III basket cells. A similar interneuronal subtype was also found in GAD65-EGFP-negative mouse. The extensive dendritic bifurcation at superficial lamina IA among horizontal afferent fibers and unique axonal targeting pattern suggests that these interneurons may play a role in direct feedforward inhibitory and disinhibitory olfactory processing. We conclude that the GAD65-GFP neurons may play distinct roles in regulating information flow and olfactory-related oscillation within the PPC in vivo.
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Affiliation(s)
- Chunzhao Zhang
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071, USA
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34
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Govindaiah G, Cox CL. Modulation of thalamic neuron excitability by orexins. Neuropharmacology 2006; 51:414-25. [PMID: 16713607 DOI: 10.1016/j.neuropharm.2006.03.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 03/09/2006] [Accepted: 03/29/2006] [Indexed: 11/29/2022]
Abstract
Orexins (hypocretins) are peptides of hypothalamic origin that play an important role in maintaining wakefulness. Reduced orexin levels have been associated with an increased incidence of narcolepsy. Considering thalamic nuclei are interconnected with virtually all neocortical regions and the thalamus has been found to produce distinct activities related to different levels of arousal, we have examined the actions of orexins on thalamic neurons using an in vitro thalamic slice preparation. The orexins (orexin-A and orexin-B) produced distinct actions within different intralaminar nuclei. Orexin-B strongly depolarized the majority of centrolateral nucleus (CL) neurons (71%), but depolarized a significantly smaller population of parafascicular nuclei (Pf) neurons (10%). In the mediodorsal thalamic nucleus (MD), orexin-B depolarized 21% of the neurons tested. Overall, orexin-B was found to be more potent than Orexin-A. Orexin-A depolarized a significantly smaller population of CL neurons (23%), but had no effect on Pf neurons. In addition, orexin-A produced a small depolarization in 28% of neurons in the thalamic reticular nucleus (TRN). Both orexin-A and orexin-B had no effect on neurons in the lateral posterior (LP), lateralodorsal (LD), posterior thalamic (Po), ventrobasal (VB) nucleus and lateral geniculate nucleus (LGN). The depolarizing actions of orexins were sufficient to alter the firing mode of these neurons from a burst- to tonic-firing mode. The excitatory actions of orexin-B result from a decrease in the apparent leak potassium current (Kleak). The orexin-B mediated excitation was also attenuated by bupivacaine suggesting the involvement of Kleak current. Further, the actions of orexin-B were occluded by the classical neurotransmitter dopamine, indicating the orexins may share similar ionic mechanisms. Thus, the depolarizing actions of orexins may play a key role in altering the firing mode of thalamic neurons associated with different states of consciousness.
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Affiliation(s)
- G Govindaiah
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL 61801, USA
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35
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Lee SH, Cox CL. Excitatory actions of vasoactive intestinal peptide on mouse thalamocortical neurons are mediated by VPAC2 receptors. J Neurophysiol 2006; 96:858-71. [PMID: 16641377 DOI: 10.1152/jn.01115.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Thalamic nuclei can generate intrathalamic rhythms similar to those observed at various arousal levels and pathophysiological conditions such as absence epilepsy. These rhythmic activities can be altered by a variety of neuromodulators that arise from brain stem regions as well as those that are intrinsic to the thalamic circuitry. Vasoactive intestinal peptide (VIP) is a neuropeptide localized within the thalamus and strongly attenuates intrathalamic rhythms via an unidentified receptor subtype. We have used transgenic mice lacking a specific VIP receptor, VPAC(2), to identify its role in VIP-mediated actions in the thalamus. VIP strongly attenuated both the slow, 2-4 Hz and spindle-like 5-8 Hz rhythmic activities in slices from wild-type mice (VPAC(2)(+/+)) but not in slices from VPAC(2) receptor knock-out mice (VPAC(2)(-/-)), which suggests a major role of VPAC(2) receptors in the antioscillatory actions of VIP. Intracellular recordings revealed that VIP depolarized all relay neurons tested from VPAC(2)(+/+) mice. In VPAC(2)(-/-) mice, however, VIP produced no membrane depolarization in 80% of neurons tested. In relay neurons from VPAC(2)+/+ mice, VIP enhanced the hyperpolarization-activated mixed cation current, I(h), via cyclic AMP activity, but VIP did not alter I(h) in VPAC(2)-/- mice. In VPAC(2)-/- mice, pituitary adenylate cyclase activating-polypeptide (PACAP) depolarized the majority of relay neurons via I(h) enhancement presumably via PAC(1) receptor activation. Our findings suggest that VIP-mediated actions are predominantly mediated by VPAC(2) receptors, but PAC(1) receptors may play a minor role. The excitatory actions of VIP and PACAP suggest these peptides may not only regulate intrathalamic rhythmic activities, but also may influence information transfer through thalamocortical circuits.
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MESH Headings
- Animals
- Cerebral Cortex/cytology
- Cerebral Cortex/drug effects
- Cyclic AMP/physiology
- Electrophysiology
- Extracellular Space/drug effects
- Extracellular Space/physiology
- In Vitro Techniques
- Interneurons/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Patch-Clamp Techniques
- Pituitary Adenylate Cyclase-Activating Polypeptide/pharmacology
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I/drug effects
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I/genetics
- Receptors, Vasoactive Intestinal Peptide, Type II/drug effects
- Receptors, Vasoactive Intestinal Peptide, Type II/genetics
- Second Messenger Systems/physiology
- Thalamus/cytology
- Thalamus/drug effects
- Vasoactive Intestinal Peptide/pharmacology
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Affiliation(s)
- Sang-Hun Lee
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL 61801, USA
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36
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Joo KM, Chung YH, Lim HC, Lee KH, Cha CI. Reduced immunoreactivities of a vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide receptor (VPAC1 receptor) in the cerebral cortex, hippocampal region, and amygdala of aged rats. Brain Res 2005; 1064:166-72. [PMID: 16269138 DOI: 10.1016/j.brainres.2005.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 09/08/2005] [Accepted: 09/25/2005] [Indexed: 11/20/2022]
Abstract
In this study, we examined expressional changes of VPAC1 receptor in aged rat brains using an immunohistochemical approach and found that its immunoreactivities are significantly reduced in the cerebral cortex, hippocampal region, and amygdala of aged rats. These results suggest that this reduction could underlie aging-associated memory/learning deficits and several other age-induced functional changes in these areas. However, the functional consequences of these down-regulations require further elucidation.
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Affiliation(s)
- Kyeung Min Joo
- Department of Anatomy, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea
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37
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Pakhotin P, Harmar AJ, Verkhratsky A, Piggins H. VIP receptors control excitability of suprachiasmatic nuclei neurones. Pflugers Arch 2005; 452:7-15. [PMID: 16283205 DOI: 10.1007/s00424-005-0003-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 09/12/2005] [Indexed: 10/25/2022]
Abstract
The role of vasoactive intestinal polypeptide (VIP) receptors on excitable properties of neurones in slices acutely prepared from the suprachiasmatic nuclei (SCN) of wild-type (WT) and VPAC(2)-receptor-deficient (Vipr2 ( -/- )) mice was studied under voltage clamp with the use of patch-clamp recording in the whole-cell configuration. The resting membrane potential in Vipr2 ( -/- ) neurones was significantly hyperpolarised as compared to WT cells (-60+/-7 vs -72+/-6 mV, p<0.01). Bath application of 100 nM VIP or the VPAC(2) receptor agonist RO 25-1553 triggered a slow inward current in a subpopulation of WT SCN neurones; the VIP-induced current was not affected by slice incubation with 25 microM of bicuculline but disappeared completely when the cells were dialysed with CsCl-containing/K(+)-free solution. Application of VIP or RO 25-1553 to neurones from Vipr2 ( -/- ) mice did not induce currents in all cells tested. Incubation of WT slices with 100 nM VIP or RO 25-1553 resulted in inhibition of fast tetrodotoxin-sensitive sodium currents and delayed rectifier K(+) currents in most of the cells tested. This effect was completely absent in cells from Vipr2 ( -/- ) mice. We postulate that VIP receptors control excitability of SCN neurones at the postsynaptic level by direct modulation of membrane potential via inhibition of K(+) channels and by tonic inhibition of sodium and potassium voltage-gated currents.
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Affiliation(s)
- Pavel Pakhotin
- Faculty of Life Sciences, The University of Manchester, 1.124 Stopford Building, Oxford Road, M13 9PT, Manchester, UK
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38
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Shaikh AG, Finlayson PG. Excitability of auditory brainstem neurons, in vivo, is increased by cyclic-AMP. Hear Res 2005; 201:70-80. [PMID: 15721562 DOI: 10.1016/j.heares.2004.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Accepted: 10/08/2004] [Indexed: 11/17/2022]
Abstract
Physiological control of auditory neural responses is critical for accurate representation of acoustic information, such as sound source localization and speech perception. Central auditory neural responses are almost certainly regulated by a range of mechanisms, including second messenger systems, such as the cAMP pathway. An increase in spontaneous neural discharge is known to accompany cochlear insults. Here we report that an increase in spontaneous as well as tone-evoked discharge can also be induced by pressure application of forskolin, a pharmacological agent that elevates intracellular cAMP level by activating adenyl cyclase. The forskolin induced increase in superior olivary complex (SOC) brainstem neurons is specific, dose-dependent, and reversible, whereas application of artificial cerebrospinal fluid (aCSF, the vehicle) does not alter activity. Forskolin-application also has a relatively greater effect on spontaneous activity compared to tone evoked responses. Blockade of the hyperpolarization-activated current, Ih, by ZD7288, consistently reversed the effects of forskolin. Based on these findings, we propose that the second messenger, cAMP, can significantly modulate neural excitability and spontaneous discharge in SOC neurons, principally by shifting the activation of Ih channels.
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Affiliation(s)
- Aasef G Shaikh
- Department of Otolaryngology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
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39
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Merriam LA, Barstow KL, Parsons RL. Pituitary adenylate cyclase-activating polypeptide enhances the hyperpolarization-activated nonselective cationic conductance, Ih, in dissociated guinea pig intracardiac neurons. ACTA ACUST UNITED AC 2005; 123:123-33. [PMID: 15518902 DOI: 10.1016/j.regpep.2004.04.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) peptides, which are co-localized with acetylcholine in preganglionic parasympathetic fibers innervating guinea pig intracardiac ganglia, depolarize and increase excitability of intracardiac neurons. Perforated patch whole cell recordings were used to test whether PACAP27-enhanced activation of Ih contributed to the increase in excitability. In current clamp, 100 nM PACAP27 increased rectification during 500-ms hyperpolarizations and increased the number of anodal break action potentials (APs). PACAP27 also increased the number of APs produced by 500-ms depolarizing currents. In voltage clamp, the effects of 100 nM PACAP27 were determined during hyperpolarizing steps from -50 mV to voltages between -60 and -120 mV. PACAP27 increased the amplitude and rate of activation of Ih. PACAP27 shifted the voltage dependence of activation of Ih by 6.6 mV. The effect of PACAP27 was eliminated by pretreatment with the Ih inhibitor ZD7288 (100 microM). The adenylyl cyclase activator forskolin (10 microM) produced a similar shift in the voltage dependence of Ih activation. We conclude that PACAP27 enhances Ih by shifting the voltage dependence of activation and propose that this effect is mediated primarily by PAC1 receptor activation of adenylyl cyclase and generation of cAMP. Furthermore, we propose that the peptide-enhanced Ih contributes to the PACAP27-induced increase in membrane excitability.
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Affiliation(s)
- Laura A Merriam
- Department of Anatomy and Neurobiology, University of Vermont, 89 Beaumont Avenue, Given C427, Burlington, VT 05405, USA
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40
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Joo KM, Chung YH, Kim MK, Nam RH, Lee BL, Lee KH, Cha CI. Distribution of vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide receptors (VPAC1, VPAC2, and PAC1 receptor) in the rat brain. J Comp Neurol 2004; 476:388-413. [PMID: 15282712 DOI: 10.1002/cne.20231] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To examine the distributions of VIP/PACAP receptors (VPAC1, VPAC2, and PAC1 receptors) in the brain and to identify the cell types that express these receptors, we performed immunohistochemistry and double immunofluorescence in the rat brain with specific antibodies. The immunohistochemistry revealed that the receptors had distinctive, complementary, and overlapping distribution patterns. High levels of the VPAC1 receptor were expressed in the cerebral cortex, hippocampal formation, deep cerebellar nuclei, thalamus, hypothalamus, and brainstem. The VPAC2 receptors were concentrated in the cerebral cortex, hippocampal formation, amygdalar regions, cerebellar cortex, deep cerebellar nuclei, hypothalamus, and brainstem. On the other hand, the PAC1 receptors had a more restricted distribution pattern in the brain, and high levels of the PAC1 receptors were confined to the cerebellar cortex, deep cerebellar nuclei, epithalamus, hypothalamus, brainstem, and white matter of many brain regions. Also, many fibers expressing the PAC1 receptors were observed in various areas, i.e., the thalamus, hypothalamus, and brainstem. The double immunofluorescence showed that the VIP/PACAP receptors were confined to the neuroglia as well as the neurons. All three types of the VIP/PACAP receptors were expressed in the astrocytes, and the PAC1 receptors were also expressed in the oligodendrocytes. These findings indicate that VIP and PACAP exert their functions through their receptors in specific locations in different combinations. We hope that this first demonstration of the distributions of the VIP/PACAP receptors provides data useful in the investigation of the mechanisms of the many functions of VIP and PACAP in the brain, which require further elucidation.
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MESH Headings
- Aging/physiology
- Animals
- Brain/cytology
- Brain/metabolism
- Immunohistochemistry
- Male
- Neuroglia/metabolism
- Neurons/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I
- Receptors, Pituitary Hormone/classification
- Receptors, Pituitary Hormone/metabolism
- Receptors, Vasoactive Intestinal Peptide/metabolism
- Receptors, Vasoactive Intestinal Peptide, Type II
- Receptors, Vasoactive Intestinal Polypeptide, Type I
- Tissue Distribution
- Vasoactive Intestinal Peptide/metabolism
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Affiliation(s)
- Kyeung Min Joo
- Department of Anatomy, Seoul National University College of Medicine, Seoul 110-799, Korea
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Notomi T, Shigemoto R. Immunohistochemical localization of Ih channel subunits, HCN1-4, in the rat brain. J Comp Neurol 2004; 471:241-76. [PMID: 14991560 DOI: 10.1002/cne.11039] [Citation(s) in RCA: 468] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hyperpolarization-activated cation currents (I(h)) contribute to various physiological properties and functions in the brain, including neuronal pacemaker activity, setting of resting membrane potential, and dendritic integration of synaptic input. Four subunits of the Hyperpolarization-activated and Cyclic-Nucleotide-gated nonselective cation channels (HCN1-4), which generate I(h), have been cloned recently. To better understand the functional diversity of I(h) in the brain, we examined precise immunohistochemical localization of four HCNs in the rat brain. Immunoreactivity for HCN1 showed predominantly cortical distribution, being intense in the neocortex, hippocampus, superior colliculus, and cerebellum, whereas those for HCN3 and HCN4 exhibited subcortical distribution mainly concentrated in the hypothalamus and thalamus, respectively. Immunoreactivity for HCN2 had a widespread distribution throughout the brain. Double immunofluorescence revealed colocalization of immunoreactivity for HCN1 and HCN2 in distal dendrites of pyramidal cells in the hippocampus and neocortex. At the electron microscopic level, immunogold particles for HCN1 and HCN2 had similar distribution patterns along plasma membrane of dendritic shafts in layer I of the neocortex and stratum lacunosum moleculare of the hippocampal CA1 area, suggesting that these subunits could form heteromeric channels. Our results further indicate that HCNs are localized not only in somato-dendritic compartments but also in axonal compartments of neurons. Immunoreactivity for HCNs often occurred in preterminal rather than terminal portions of axons and in specific populations of myelinated axons. We also found HCN2-immunopositive oligodendrocytes including perineuronal oligodendrocytes throughout the brain. These results support previous electrophysiological findings and further suggest unexpected roles of I(h) channels in the brain.
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Affiliation(s)
- Takuya Notomi
- Division of Cerebral Structure, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan.
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