1
|
Katz BM, Walton LR, Houston KM, Cerri DH, Shih YYI. Putative neurochemical and cell type contributions to hemodynamic activity in the rodent caudate putamen. J Cereb Blood Flow Metab 2023; 43:481-498. [PMID: 36448509 PMCID: PMC10063835 DOI: 10.1177/0271678x221142533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/28/2022] [Accepted: 10/21/2022] [Indexed: 12/02/2022]
Abstract
Functional magnetic resonance imaging (fMRI) is widely used by researchers to noninvasively monitor brain-wide activity. The traditional assumption of a uniform relationship between neuronal and hemodynamic activity throughout the brain has been increasingly challenged. This relationship is now believed to be impacted by heterogeneously distributed cell types and neurochemical signaling. To date, most cell-type- and neurotransmitter-specific influences on hemodynamics have been examined within the cortex and hippocampus of rodent models, where glutamatergic signaling is prominent. However, neurochemical influences on hemodynamics are relatively unknown in largely GABAergic brain regions such as the rodent caudate putamen (CPu). Given the extensive contribution of CPu function and dysfunction to behavior, and the increasing focus on this region in fMRI studies, improved understanding of CPu hemodynamics could have broad impacts. Here we discuss existing findings on neurochemical contributions to hemodynamics as they may relate to the CPu with special consideration for how these contributions could originate from various cell types and circuits. We hope this review can help inform the direction of future studies as well as interpretation of fMRI findings in the CPu.
Collapse
Affiliation(s)
- Brittany M Katz
- Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lindsay R Walton
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kaiulani M Houston
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | - Domenic H Cerri
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yen-Yu Ian Shih
- Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| |
Collapse
|
2
|
Choudhury H, Pandey M, Chin PX, Phang YL, Cheah JY, Ooi SC, Mak KK, Pichika MR, Kesharwani P, Hussain Z, Gorain B. Transferrin receptors-targeting nanocarriers for efficient targeted delivery and transcytosis of drugs into the brain tumors: a review of recent advancements and emerging trends. Drug Deliv Transl Res 2018; 8:1545-1563. [PMID: 29916012 DOI: 10.1007/s13346-018-0552-2] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Treatment of glioblastoma multiforme (GBM) is a predominant challenge in chemotherapy due to the existence of blood-brain barrier (BBB) which restricts delivery of chemotherapeutic agents to the brain together with the problem of drug penetration through hard parenchyma of the GBM. With the structural and mechanistic elucidation of the BBB under both physiological and pathological conditions, it is now viable to target central nervous system (CNS) disorders utilizing the presence of transferrin (Tf) receptors (TfRs). However, overexpression of these TfRs on the GBM cell surface can also help to avoid restrictions of GBM cells to deliver chemotherapeutic agents within the tumor. Therefore, targeting of TfR-mediated delivery could counteract drug delivery issues in GBM and create a delivery system that could cross the BBB effectively to utilize ligand-conjugated drug complexes through receptor-mediated transcytosis. Hence, approach towards successful delivery of antitumor agents to the gliomas has been making possible through targeting these overexpressed TfRs within the CNS and glioma cells. This review article presents a thorough analysis of current understanding on Tf-conjugated nanocarriers as efficient drug delivery system.
Collapse
Affiliation(s)
- Hira Choudhury
- Department of Pharmaceutical Technology, School of Pharmacy, International Medical University, 57000, Kuala Lumpur, Malaysia.
| | - Manisha Pandey
- Department of Pharmaceutical Technology, School of Pharmacy, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Pei Xin Chin
- School of Pharmacy, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Yee Lin Phang
- School of Pharmacy, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Jeng Yuen Cheah
- School of Pharmacy, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Shu Chien Ooi
- School of Pharmacy, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Kit-Kay Mak
- School of Postgraduate Studies and Research, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Mallikarjuna Rao Pichika
- Department of Pharmaceutical Chemistry, School of Pharmacy, International Medical University, 57000, Kuala Lumpur, Malaysia.,Centre for Bioactive Molecules and Drug Delivery, Institute for Research, Development and Innovation, International Medical University, 57000, Kuala Lumpur, Malaysia
| | - Prashant Kesharwani
- Pharmaceutics Division, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, 226031, India
| | - Zahid Hussain
- Department of Pharmaceutics, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, 42300, Puncak Alam, Malaysia
| | - Bapi Gorain
- Faculty of Pharmacy, Lincoln University College, Petalling Jaya, 47301, Kuala Lumpur, Selangor, Malaysia
| |
Collapse
|
3
|
Hotta H. Neurogenic control of parenchymal arterioles in the cerebral cortex. PROGRESS IN BRAIN RESEARCH 2016; 225:3-39. [DOI: 10.1016/bs.pbr.2016.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
4
|
Konsolaki E, Skaliora I. Premature Aging Phenotype in Mice Lacking High-Affinity Nicotinic Receptors: Region-Specific Changes in Layer V Pyramidal Cell Morphology. Cereb Cortex 2014; 25:2138-48. [PMID: 24554727 DOI: 10.1093/cercor/bhu019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The mechanisms by which aging leads to alterations in brain structure and cognitive deficits are unclear. Α deficient cholinergic system has been implicated as one of the main factors that could confer a heightened vulnerability to the aging process, and mice lacking high-affinity nicotinic receptors (β2(-/-)) have been proposed as an animal model of accelerated cognitive aging. To date, however, age-related changes in neuronal microanatomy have not been studied in these mice. In the present study, we examine the neuronal structure of yellow fluorescent protein (YFP(+)) layer V neurons in 2 cytoarchitectonically distinct cortical regions in wild-type (WT) and β2(-/-) animals. We find that (1) substantial morphological differences exist between YFP(+) cells of the anterior cingulate cortex (ACC) and primary visual cortex (V1), in both genotypes; (2) in WT animals, ACC cells are more susceptible to aging compared with cells in V1; and (3) β2 deletion is associated with a regionally and temporally specific increase in vulnerability to aging. ACC cells exhibit a prematurely aged phenotype already at 4-6 months, whereas V1 cells are spared in adulthood but strongly affected in old animals. Collectively, our data reveal region-specific synergistic effects of aging and genotype and suggest distinct vulnerabilities in V1 and ACC neurons.
Collapse
Affiliation(s)
- Eleni Konsolaki
- Neurophysiology Laboratory, Division of Developmental Biology, Biomedical Research Foundation of the Academy of Athens, Athens 115 27, Greece
| | - Irini Skaliora
- Neurophysiology Laboratory, Division of Developmental Biology, Biomedical Research Foundation of the Academy of Athens, Athens 115 27, Greece
| |
Collapse
|
5
|
Cheng Y, Morshed RA, Auffinger B, Tobias AL, Lesniak MS. Multifunctional nanoparticles for brain tumor imaging and therapy. Adv Drug Deliv Rev 2014; 66:42-57. [PMID: 24060923 PMCID: PMC3948347 DOI: 10.1016/j.addr.2013.09.006] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 08/28/2013] [Accepted: 09/13/2013] [Indexed: 12/16/2022]
Abstract
Brain tumors are a diverse group of neoplasms that often carry a poor prognosis for patients. Despite tremendous efforts to develop diagnostic tools and therapeutic avenues, the treatment of brain tumors remains a formidable challenge in the field of neuro-oncology. Physiological barriers including the blood-brain barrier result in insufficient accumulation of therapeutic agents at the site of a tumor, preventing adequate destruction of malignant cells. Furthermore, there is a need for improvements in brain tumor imaging to allow for better characterization and delineation of tumors, visualization of malignant tissue during surgery, and tracking of response to chemotherapy and radiotherapy. Multifunctional nanoparticles offer the potential to improve upon many of these issues and may lead to breakthroughs in brain tumor management. In this review, we discuss the diagnostic and therapeutic applications of nanoparticles for brain tumors with an emphasis on innovative approaches in tumor targeting, tumor imaging, and therapeutic agent delivery. Clinically feasible nanoparticle administration strategies for brain tumor patients are also examined. Furthermore, we address the barriers towards clinical implementation of multifunctional nanoparticles in the context of brain tumor management.
Collapse
Affiliation(s)
- Yu Cheng
- The Brain Tumor Center, The University of Chicago, Chicago, IL, USA
| | - Ramin A Morshed
- The Brain Tumor Center, The University of Chicago, Chicago, IL, USA
| | - Brenda Auffinger
- The Brain Tumor Center, The University of Chicago, Chicago, IL, USA
| | - Alex L Tobias
- The Brain Tumor Center, The University of Chicago, Chicago, IL, USA
| | - Maciej S Lesniak
- The Brain Tumor Center, The University of Chicago, Chicago, IL, USA.
| |
Collapse
|
6
|
Morshed RA, Cheng Y, Auffinger B, Wegscheid ML, Lesniak MS. The potential of polymeric micelles in the context of glioblastoma therapy. Front Pharmacol 2013; 4:157. [PMID: 24416018 PMCID: PMC3874582 DOI: 10.3389/fphar.2013.00157] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/29/2013] [Indexed: 12/12/2022] Open
Abstract
Glioblastoma multiforme (GBM), a type of malignant glioma, is the most common form of brain cancer found in adults. The current standard of care for GBM involves adjuvant temozolomide-based chemotherapy in conjunction with radiotherapy, yet patients still suffer from poor outcomes with a median survival of 14.6 months. Many novel therapeutic agents that are toxic to GBM cells in vitro cannot sufficiently accumulate at the site of an intracranial tumor after systemic administration. Thus, new delivery strategies must be developed to allow for adequate intratumoral accumulation of such therapeutic agents. Polymeric micelles offer the potential to improve delivery to brain tumors as they have demonstrated the capacity to be effective carriers of chemotherapy drugs, genes, and proteins in various preclinical GBM studies. In addition to this, targeting moieties and trigger-dependent release mechanisms incorporated into the design of these particles can promote more specific delivery of a therapeutic agent to a tumor site. However, despite these advantages, there are currently no micelle formulations targeting brain cancer in clinical trials. Here, we highlight key aspects of the design of polymeric micelles as therapeutic delivery systems with a review of their clinical applications in several non-brain tumor cancer types. We also discuss their potential to serve as nanocarriers targeting GBM, the major barriers preventing their clinical implementation in this disease context, as well as current approaches to overcome these limitations.
Collapse
Affiliation(s)
- Ramin A Morshed
- The Brain Tumor Center, The University of Chicago Pritzker School of Medicine Chicago, IL, USA
| | - Yu Cheng
- The Brain Tumor Center, The University of Chicago Pritzker School of Medicine Chicago, IL, USA
| | - Brenda Auffinger
- The Brain Tumor Center, The University of Chicago Pritzker School of Medicine Chicago, IL, USA
| | - Michelle L Wegscheid
- The Brain Tumor Center, The University of Chicago Pritzker School of Medicine Chicago, IL, USA
| | - Maciej S Lesniak
- The Brain Tumor Center, The University of Chicago Pritzker School of Medicine Chicago, IL, USA
| |
Collapse
|
7
|
Electroacupuncture acutely improves cerebral blood flow and attenuates moderate ischemic injury via an endothelial mechanism in mice. PLoS One 2013; 8:e56736. [PMID: 23418594 PMCID: PMC3572074 DOI: 10.1371/journal.pone.0056736] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/14/2013] [Indexed: 11/19/2022] Open
Abstract
Electroacupuncture (EA) is a novel therapy based on traditional acupuncture combined with modern eletrotherapy that is currently being investigated as a treatment for acute ischemic stroke. Here, we studied whether acute EA stimulation improves tissue and functional outcome following experimentally induced cerebral ischemia in mice. We hypothesized that endothelial nitric oxide synthase (eNOS)-mediated perfusion augmentation was related to the beneficial effects of EA by interventions in acute ischemic injury. EA stimulation at Baihui (GV20) and Dazhui (GV14) increased cerebral perfusion in the cerebral cortex, which was suppressed in eNOS KO, but there was no mean arterial blood pressure (MABP) response. The increased perfusion elicited by EA were completely abolished by a muscarinic acetylcholine receptor (mAChR) blocker (atropine), but not a β-adrenergic receptor blocker (propranolol), an α-adrenergic receptor blocker (phentolamine), or a nicotinic acetylcholine receptor (nAChR) blocker (mecamylamine). In addition, EA increased acetylcholine (ACh) release and mAChR M3 expression in the cerebral cortex. Acute EA stimulation after occlusion significantly reduced infarct volume by 34.5% when compared to a control group of mice at 24 h after 60 min-middle cerebral artery occlusion (MCAO) (moderate ischemic injury), but not 90-min MCAO (severe ischemic injury). Furthermore, the impact of EA on moderate ischemic injury was totally abolished in eNOS KO. Consistent with a smaller infarct size, acute EA stimulation led to prominent improvement of neurological function and vestibule-motor function. Our results suggest that acute EA stimulation after moderate focal cerebral ischemia, but not severe ischemia improves tissue and functional recovery and ACh/eNOS-mediated perfusion augmentation might be related to these beneficial effects of EA by interventions in acute ischemic injury.
Collapse
|
8
|
Negraes PD, Lameu C, Hayashi MAF, Melo RL, Camargo ACM, Ulrich H. The snake venom peptide Bj-PRO-7a is a M1 muscarinic acetylcholine receptor agonist. Cytometry A 2010; 79:77-83. [DOI: 10.1002/cyto.a.20963] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
9
|
Uchida S, Hotta H. Cerebral Cortical Vasodilatation Mediated by Nicotinic Cholinergic Receptors: Effects of Old Age and of Chronic Nicotine Exposure. Biol Pharm Bull 2009; 32:341-4. [DOI: 10.1248/bpb.32.341] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Sae Uchida
- Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology
| | - Harumi Hotta
- Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology
| |
Collapse
|
10
|
Hahn B, Ross TJ, Wolkenberg FA, Shakleya DM, Huestis MA, Stein EA. Performance effects of nicotine during selective attention, divided attention, and simple stimulus detection: an fMRI study. ACTA ACUST UNITED AC 2008; 19:1990-2000. [PMID: 19073624 DOI: 10.1093/cercor/bhn226] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Attention-enhancing effects of nicotine appear to depend on the nature of the attentional function. Underlying neuroanatomical mechanisms, too, may vary depending on the function modulated. This functional magnetic resonance imaging study recorded blood oxygen level-dependent (BOLD) activity in minimally deprived smokers during tasks of simple stimulus detection, selective attention, or divided attention after single-blind application of a transdermal nicotine (21 mg) or placebo patch. Smokers' performance in the placebo condition was unimpaired as compared with matched nonsmokers. Nicotine reduced reaction time (RT) in the stimulus detection and selective attention but not divided attention condition. Across all task conditions, nicotine reduced activation in frontal, temporal, thalamic, and visual regions and enhanced deactivation in so-called "default" regions. Thalamic effects correlated with RT reduction selectively during stimulus detection. An interaction with task condition was observed in middle and superior frontal gyri, where nicotine reduced activation only during stimulus detection. A visuomotor control experiment provided evidence against nonspecific effects of nicotine. In conclusion, although prefrontal activity partly displayed differential modulation by nicotine, most BOLD effects were identical across tasks, despite differential performance effects, suggesting that common neuronal mechanisms can selectively benefit different attentional functions. Overall, the effects of nicotine may be explained by increased functional efficiency and downregulated task-independent "default" functions.
Collapse
Affiliation(s)
- Britta Hahn
- Neuroimaging Research Branch, NIH/National Institute on Drug Abuse-Intramural Research Program (IRP), BiomedicalResearch Center, Baltimore, MD 21224, USA.
| | | | | | | | | | | |
Collapse
|
11
|
Nery AA, Trujillo CA, Lameu C, Konno K, Oliveira V, Camargo ACM, Ulrich H, Hayashi MAF. A novel physiological property of snake bradykinin-potentiating peptides-reversion of MK-801 inhibition of nicotinic acetylcholine receptors. Peptides 2008; 29:1708-15. [PMID: 18598727 DOI: 10.1016/j.peptides.2008.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/03/2008] [Accepted: 06/05/2008] [Indexed: 11/26/2022]
Abstract
The first naturally occurring angiotensin-converting enzyme (ACE) inhibitors described are pyroglutamyl proline-rich oligopeptides, found in the venom of the viper Bothrops jararaca, and named as bradykinin-potentiating peptides (BPPs). Biochemical and pharmacological properties of these peptides were essential for the development of Captopril, the first active site-directed inhibitor of ACE, currently used for the treatment of human hypertension. However, a number of data have suggested that the pharmacological activity of BPPs could not only be explained by their inhibitory action on enzymatic activity of somatic ACE. In fact, we showed recently that the strong and long-lasting anti-hypertensive effect of BPP-10c [<ENWPHPQIPP] is independent of somatic ACE inhibition. On the other hand, nicotinic acetylcholine receptors expressed in blood vessels have been related to blood pressure regulation. Therefore, we have studied the effects of BPP-10c on acetylcholine receptor function in the PC12 pheochromocytoma cell line, which following induction to neuronal differentiation expresses most of the nicotinic receptor subtypes. BPP-10c did not induce receptor-mediated ion flux, nor potentiated carbamoylcholine-provoked receptor activity as determined by whole-cell recording. This peptide, however, alleviated MK-801-induced inhibition of nicotinic acetylcholine receptor activity. Although more data are needed for understanding the mechanism of the BPP-10c effect on nicotinic receptor activity and its relationship with the anti-hypertensive activity, this work reveals possible therapeutic applications for BPP-10c in establishing normal acetylcholine receptor activity.
Collapse
Affiliation(s)
- Arthur A Nery
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP 05508-900, São Paulo, SP, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Court JA, Johnson M, Religa D, Keverne J, Kalaria R, Jaros E, McKeith IG, Perry R, Naslund J, Perry EK. Attenuation of Abeta deposition in the entorhinal cortex of normal elderly individuals associated with tobacco smoking. Neuropathol Appl Neurobiol 2005; 31:522-35. [PMID: 16150123 DOI: 10.1111/j.1365-2990.2005.00674.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Investigating correlates of tobacco smoking provides the only currently available opportunity of examining effects of long-term exposure of nicotinic receptors on a specific nicotinic agonist in human. Alzheimer-type pathology (Abeta and abnormally phosphorylated tau assessed on the basis of AT8 immunoreactivity) together with vascular markers has been compared in age-matched groups of normal elderly smokers and non-smokers in the entorhinal cortex, an area of noted age-related pathology. The density of total Abeta and diffuse Abeta immunoreactivity, together with formic acid-extractable Abeta42 but not Abeta40, was reduced in smokers (n = 10-18) compared with non-smokers (n = 10-20) (P < 0.05). There was also a reduced percentage of cortical and leptomeningeal vessels with associated Abeta immunoreactivity in smokers (n = 13) compared with non-smokers (n = 14) (P < 0.005 and 0.05, respectively). There was a significant inverse correlation between formic acid-extractable Abeta42 and pack years (n = 34, r = -0.389, P = 0.025), with a similar trend for total Abeta immunoreactivity which did not reach statistical significance (n = 30, r = -0.323, P = 0.082). In contrast, there were no significant group differences for vascular markers (collagen IV, alpha-actin or glucose transporter 1), AT8 immunoreactivity or phosphate-buffered saline-soluble Abeta peptides, and no significant associations with gender for any of the measured parameters. These findings are consistent with previously reported reductions in histologically assessed amyloid plaques in aged human brain associated with tobacco use and dramatic lessening of Abeta deposits in APPsw mice after nicotine treatment. Development of nicotinic drugs to protect against beta-amyloidosis as one of the principal pathological hallmarks of brain ageing and Alzheimer's disease is indicated.
Collapse
Affiliation(s)
- J A Court
- MRC Building, Newcastle General Hospital, Westgate Road, Newcastle upon Tyne, NE4 6BE, UK.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Hawkins BT, Egleton RD, Davis TP. Modulation of cerebral microvascular permeability by endothelial nicotinic acetylcholine receptors. Am J Physiol Heart Circ Physiol 2005; 289:H212-9. [PMID: 15708958 DOI: 10.1152/ajpheart.01210.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nicotine increases the permeability of the blood-brain barrier in vivo. This implies a possible role for nicotinic acetylcholine receptors in the regulation of cerebral microvascular permeability. Expression of nicotinic acetylcholine receptor subunits in cerebral microvessels was investigated with immunofluorescence microscopy. Positive immunoreactivity was found for receptor subunits alpha3, alpha5, alpha7, and beta2, but not subunits alpha4, beta3, or beta4. Blood-brain barrier permeability was assessed via in situ brain perfusion with [14C]sucrose. Nicotine increased the rate of sucrose entry into the brain from 0.3 +/- 0.1 to 1.1 +/- 0.2 microl.g(-1).min(-1), as previously described. This nicotine-induced increase in blood-brain barrier permeability was significantly attenuated by both the blood-brain barrier-permeant nicotinic antagonist mecamylamine and the blood-brain barrier-impermeant nicotinic antagonist hexamethonium to 0.5 +/- 0.2 and 0.3 +/- 0.2 microl.g(-1).min(-1), respectively. These data suggest that nicotinic acetylcholine receptors expressed on the cerebral microvascular endothelium mediate nicotine-induced changes in blood-brain barrier permeability.
Collapse
Affiliation(s)
- Brian T Hawkins
- Program in Neuroscience, Univ. of Arizona College of Medicine, 1501 N. Campbell Ave., Tucson, AZ 85724-5050, USA
| | | | | |
Collapse
|
14
|
Abbruscato TJ, Lopez SP, Roder K, Paulson JR. Regulation of Blood-Brain Barrier Na,K,2Cl-Cotransporter through Phosphorylation during in Vitro Stroke Conditions and Nicotine Exposure. J Pharmacol Exp Ther 2004; 310:459-68. [PMID: 15051802 DOI: 10.1124/jpet.104.066274] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nicotine, a major constituent of tobacco smoke, has important effects on brain recovery after focal ischemia (Wang et al., 1997). The purpose of this work is to systematically test the effects of nicotine during stroke conditions on blood-brain barrier (BBB) potassium transport, protein expression of the Na,K,2Cl-cotransporter (NKCC), and cell signaling pathways that control NKCC activity at the BBB. Confluent bovine brain microvessel endothelial cells (BBMECs) were exposed to both a hypoxic/aglycemic (H/A) environment to model BBB function during stroke conditions and nicotine and cotinine (N/C) to model plasma levels seen in smokers. BBMECs exhibit both Na,K-ATPase and NKCC activity (60 and 34 nmol/min/g, respectively) that contribute to 98% of the K(+) uptake in cultured endothelial cells. An adaptive up-regulation of NKCC activity was identified to occur on the basolateral surface of the BBB after in vitro stroke conditions. Twenty-four hours of N/C exposure, at doses equivalent to plasma levels of smokers, combined with 6 h of H/A, reduced NKCC protein expression and total NKCC activity (shown by bumetanide-sensitive (86)RB uptake) compared with 6 h of H/A alone (P < 0.01). Basolateral K(+) transport was found to be modulated by nicotinic acetylcholine receptors expressed at the BBB. NKCC activity on the basolateral surface of the BBB is controlled by an ongoing phosphorylation/dephosphorylation processes. We have identified a potential mechanism in altered BBB response to stroke conditions with prior N/C exposure directly implicating damage to brain-to-blood K(+) transport mediated at the BBB and perhaps neuronal recovery after stroke.
Collapse
Affiliation(s)
- Thomas J Abbruscato
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, School of Pharmacy, 1300 Coulter, Amarillo, TX 79106, USA.
| | | | | | | |
Collapse
|
15
|
Abstract
Cortical microvessels receive a cholinergic input that originates primarily from basal forebrain neurons which, upon stimulation, induce significant increases in cortical perfusion together with a dilation of intracortical microvessels. Heterogeneous mAChRs have been detected in cortical microvessels with expression of M2 and M5 subtypes in endothelial cells, while M1 and M3, and possibly M5 mAChR subtypes, were expressed in smooth muscle cells. Application of ACh to isolated and pressurized microarterioles, whether at basal tone or pharmacologically preconstricted, elicited only a dilation. This response was dependent on NO production, and was mediated by a mAChR, the pharmacology of which correlated best with the M5 receptor subtype. ACh afferents also project to intracortical neurons that synthesize NO and VIP. These correspond to distinct sub-populations of GABA interneurons which were found to send numerous projections to local microvessels. Preliminary results suggest expression of the VPAC1 receptor in the smooth muscle cells of intracortical arterioles, where it could mediate dilation as it does in cerebral arteries. Together these results indicate that basal forebrain ACh fibers can directly affect the cortical microvascular bed, but further suggest that specific populations of GABA interneurons could serve as a functional relay to adapt perfusion to locally increased neuronal activity. In confirmed cases of Alzheimer's disease, we found a severe ACh denervation of both cortical microvessels and NO neurons, suggesting that two important regulators of cortical perfusion are dysfunctional in this pathology.
Collapse
Affiliation(s)
- Edith Hamel
- Laboratory of Cerebrovascular Research, Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada.
| |
Collapse
|
16
|
Tayebati SK, Di Tullio MA, Tomassoni D, Amenta F. Localization of the m5 muscarinic cholinergic receptor in rat circle of Willis and pial arteries. Neuroscience 2003; 122:205-11. [PMID: 14596861 DOI: 10.1016/s0306-4522(03)00513-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The expression and microanatomical localization of the muscarinic cholinergic m5 receptor subtype was investigated in rat circle of Willis and pial arteries by in situ hybridization, immunoblotting and immunohistochemistry. In situ hybridization histochemistry revealed a strong signal in the endothelium of circle of Willis and pial arteries and a moderate signal in the tunica media of the same arteries, within smooth muscle. Exposure of membranes of arteries to anti-m5 receptor protein antibodies caused the development of a band of approximately 81 kDa. Immunohistochemistry revealed the accumulation of m5 receptor protein immunoreactivity primarily within endothelium of circle of Willis and cerebral arteries and to a lesser extent in the tunica media, within smooth muscle. Medium (external diameter 200-100 microm) and small-sized (external diameter smaller than 100 microm) pial arteries displayed a significantly higher immune staining than large-sized pial arteries or circle of Willis arteries. The above data that are consistent with recent functional studies reporting cholinergic dilation of cerebral blood vessels mediated via a m5 receptor, have shown that both endothelial and muscular components of cerebral arteries synthesize and express a muscarinic m5 receptor. In view of the peculiar localization in cerebral vessels, handling of the muscarinic m5 receptor may be considered as an approach in the treatment of cerebrovascular disease.
Collapse
Affiliation(s)
- S K Tayebati
- Sezione di Anatomia Umana, Dipartimento di Scienze Farmacologiche e Medicina Sperimentale, Università di Camerino, Via Scalzino 3, 62032 Camerino, Italy.
| | | | | | | |
Collapse
|
17
|
Moccia F, Frost C, Berra-Romani R, Tanzi F, Adams DJ. Expression and function of neuronal nicotinic ACh receptors in rat microvascular endothelial cells. Am J Physiol Heart Circ Physiol 2003; 286:H486-91. [PMID: 14512281 DOI: 10.1152/ajpheart.00620.2003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The expression and function of nicotinic ACh receptors (nAChRs) in rat coronary microvascular endothelial cells (CMECs) were examined using RT-PCR and whole cell patch-clamp recording methods. RT-PCR revealed expression of mRNA encoding for the subunits alpha(2), alpha(3), alpha(4), alpha(5), alpha(7), beta(2), and beta(4) but not beta(3). Focal application of ACh evoked an inward current in isolated CMECs voltage clamped at negative membrane potentials. The current-voltage relationship of the ACh-induced current exhibited marked inward rectification and a reversal potential (E(rev)) close to 0 mV. The cholinergic agonists nicotine, epibatidine, and cytisine activated membrane currents similar to those evoked by ACh. The nicotine-induced current was abolished by the neuronal nAChR antagonist mecamylamine. The direction and magnitude of the shift in E(rev) of nicotine-induced current as a function of extracellular Na(+) concentration indicate that the nAChR channel is cation selective and follows that predicted by the Goldman-Hodgkin-Katz equation assuming K(+)/Na(+) permeability ratio of 1.11. In fura-2-loaded CMECs, application of ACh, but not of nicotine, elicited a transient increase in intracellular free Ca(2+) concentration. Taken together, these results demonstrate that neuronal nAChR activation by cholinergic agonists evokes an inward current in CMECs carried primarily by Na(+), which may contribute to the plasma nicotine-induced changes in microvascular permeability and reactivity induced by elevations in plasma nicotine.
Collapse
Affiliation(s)
- F Moccia
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | | | | | | | | |
Collapse
|
18
|
Martínez-Rodríguez R, Toledano A, Alvarez MI, Turégano L, Colman O, Rosés P, Gómez de Segura I, De Miguel E. Chronic nicotine administration increases NGF-like immunoreactivity in frontoparietal cerebral cortex. J Neurosci Res 2003; 73:708-16. [PMID: 12929138 DOI: 10.1002/jnr.10688] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nicotine/nicotine agonists, which have been proposed as therapeutic agents for the treatment of Alzheimer's disease and other neurodegenerative disorders, produce a wide variety of effects on the nervous system. Some mechanisms involved remain poorly understood. In this work, immunohistochemical techniques were used to determine the effect of nicotine on nerve growth factor (NGF) in the frontoparietal (motor, somatosensory) brain cortex of the albino rat. Nicotine was chronically administered intraperitoneally using osmotic pumps (0.35 mg nicotine base/kg body weight/day for 14 days). An increase in the number and the immunoreaction intensity of NGF-like positive pyramidal and nonpyramidal neurons of these cortical areas was observed after treatment. Immunopositive astroglial cells were always seen in sections of treated animals but not in controls. The neuropil of control animals was, in general, devoid of reaction, but in treated animals, immunopositive prolongations were located randomly, some in close association with capillaries. At the electron microscopic level, these prolongations were demonstrated as belonging to neurons (dendrites and axons) and astroglial cells. Nicotinic activation of selected neurons and glial cells seems to trigger NGF/neurotrophic mechanisms, suggesting their use may be of benefit in prevention and treatment of neurodegenerative diseases.
Collapse
|
19
|
Graham AJ, Ray MA, Perry EK, Jaros E, Perry RH, Volsen SG, Bose S, Evans N, Lindstrom J, Court JA. Differential nicotinic acetylcholine receptor subunit expression in the human hippocampus. J Chem Neuroanat 2003; 25:97-113. [PMID: 12663058 DOI: 10.1016/s0891-0618(02)00100-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels composed of alpha and beta subunits with specific structural, functional and pharmacological properties. In this study the distribution of alpha3, alpha4, alpha7, beta2 and beta4 nAChR subunits in the human hippocampus was investigated using immunohistochemistry. Most pyramidal neurons, pre-alpha cells of the entorhinal cortex and dentate granule cells were immunoreactive for all subunits. Small islands of alpha7 immunoreactive cells were present in the outer presubiculum. alpha4 and beta2, and alpha3, alpha4 and beta2 immunoreactive fibre tracts were present in the stratum radiatum and subiculum, respectively, suggesting nAChRs may play a role in modulating inputs to the hippocampus via Schaffer collaterals and along the perforant pathway. Some astrocytes were immunoreactive for alpha3, alpha7 and beta4 subunits. Immunoreactivity to all subunits was noted in association with blood vessels. These results indicate the involvement of multiple nAChR subtypes in the modulation of both neuronal and non-neuronal functions in the human hippocampus.
Collapse
Affiliation(s)
- A J Graham
- Joint MRC-University of Newcastle upon Tyne, Centre Development in Clinical Brain Ageing, MRC Building, Newcastle General Hospital, Newcastle upon Tyne NE4 6BE, UK.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Abbruscato TJ, Lopez SP, Mark KS, Hawkins BT, Davis TP. Nicotine and cotinine modulate cerebral microvascular permeability and protein expression of ZO-1 through nicotinic acetylcholine receptors expressed on brain endothelial cells. J Pharm Sci 2002; 91:2525-38. [PMID: 12434396 DOI: 10.1002/jps.10256] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The blood-brain barrier (BBB) adapts to a variety of pathological processes. Little is known about the effects of nicotine exposure on BBB function and the ability to adapt to stroke conditions. We have demonstrated, using a well-characterized in vitro BBB model, bovine brain microvessel endothelial cells (BBMEC) model, that nicotine and its major metabolite, cotinine, modulate BBB integrity by opening the paracellular route of solute entry into the brain. Additionally, nicotine and cotinine together increase the permeability change observed after 6 h of hypoxia/aglycemia, an in vitro model of stroke. This has important implications for how the BBB initially adapts to stroke in an environment that is previously exposed to nicotine. Nicotine and cotinine exposure also resulted in reduced ZO-1 immunoreactivity (tight junctional protein) that occurred in a time-dependent manner. Interestingly, attenuation of bovine brain microvessel endothelial cell (BBMEC) ZO-1 protein expression was reversed using 10 nM BGT, an alpha7 nicotinic acetycholine receptor (nAChR) antagonist, suggesting that the effects of nicotine on BBMEC protein expression of ZO-1 protein are mediated by nAChR expressed on brain endothelial cells. In addition to alpha7, we found that BBMEC also contain positive immunoreactivity for the alpha3, alpha5, beta2, beta3 nAChR subunit. Both alpha7 and beta2 nAChR subunit protein levels decreased with prior nicotine and cotinine exposure. These data provide evidence that nicotine and cotinine alter BBB permeability and tight junctional protein expression of ZO-1, thereby altering the BBB response to stroke conditions. These changes in brain endothelial cell paracellular permeability are believed to be associated with nicotine binding to nAChRs present at the BBB.
Collapse
Affiliation(s)
- Thomas J Abbruscato
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, School of Pharmacy, 1300 Coulter, Amarillo, Texas 79106, USA.
| | | | | | | | | |
Collapse
|
21
|
Graham A, Court JA, Martin-Ruiz CM, Jaros E, Perry R, Volsen SG, Bose S, Evans N, Ince P, Kuryatov A, Lindstrom J, Gotti C, Perry EK. Immunohistochemical localisation of nicotinic acetylcholine receptor subunits in human cerebellum. Neuroscience 2002; 113:493-507. [PMID: 12150770 DOI: 10.1016/s0306-4522(02)00223-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Neuronal nicotinic acetylcholine receptors are members of the ligand-gated ion channel superfamily composed of alpha and beta subunits with specific structural, functional and pharmacological properties. In this study we have used immunohistochemistry to investigate the presence of nicotinic acetylcholine receptor subunits in human cerebellum. Tissue was obtained at autopsy from eight adult individuals (aged 36-56 years). Histological sections were prepared from formalin-fixed paraffin-embedded material. alpha 3, alpha 4, alpha 6, alpha 7, beta 2, and beta 4 subunits were present in this brain area associated with both neuronal and non-neuronal cell types. Most Purkinje cells were immunoreactive for all the above subunits, but most strongly for alpha 4 and alpha 7. A proportion of granule cell somata were immunoreactive for all subunits except alpha 3. Punctate immunoreactivity in Purkinje cell and granule cell layers was evident with antibodies against alpha 3, alpha 4, alpha 6, and alpha 7 in parallel with synaptophysin immunoreactivity, suggesting the presence of these subunits on nerve terminals in the human cerebellum. All subunits were present in the dentate nucleus associated with neurones and cell processes. Strong immunoreactivity of neuropil in both the molecular and granule cell layers and within the dentate nucleus was noted with alpha 4, alpha 7 and beta 4 subunits. Astrocytes and astrocytic cell processes appeared to be immunoreactive for alpha 7 and cell processes observed in white matter, also possibly astrocytic, were immunoreactive for beta2. Immunoreactivity to all subunits was noted in association with blood vessels. We suggest that nicotinic acetylcholine receptor subunits may be involved in the modulation of cerebellar activity. Further investigations are warranted to evaluate the participation of nicotinic acetylcholine receptors in cerebellar pathology associated with both developmental and age-related disorders.
Collapse
Affiliation(s)
- A Graham
- Joint MRC-University of Newcastle upon Tyne, Centre Development in Clinical Brain Ageing, MRC Building, Newcastle General Hospital, Westgate Road, NE4 6BE, Newcastle upon Tyne, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Penschuck S, Chen-Bee CH, Prakash N, Frostig RD. In vivo modulation of a cortical functional sensory representation shortly after topical cholinergic agent application. J Comp Neurol 2002; 452:38-50. [PMID: 12205708 DOI: 10.1002/cne.10361] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The aim of the present study was to determine whether cholinergic increase in the size of a functional representation (collective evoked response from a large population of neurons) can be observed shortly (within an hour) after treatment onset and whether nicotinic receptors can participate in this type of modulation. Cholinergic agonist application has been found previously to increase the response of a single cortical neuron to a stimulus. Also, pairing cholinergic basal forebrain stimulation with delivery of a tone has been reported to increase the size of that tone's functional representation. Whereas the increase in a single cortical neuron response can occur within seconds after cholinergic agonist application, to date the increase in the size of a functional representation has only been investigated within one to several weeks after the onset of pairing basal forebrain stimulation with tone delivery. Furthermore, primarily muscarinic receptors have been implicated in these types of changes in cortical activity. By using optical imaging of intrinsic signals in vivo, we found that the size of a whisker's functional representation in the primary somatosensory cortex of the rat increases substantially within 69 or 46 minutes after topical application of either a muscarinic or nicotinic agonist to the exposed cortex, respectively, and decreases within 23 minutes after topical application of a muscarinic antagonist. For each cholinergic agent, we verified that delivery of a cholinergic agent by means of topical application can lead to the agent's successful penetration through the cortical layers in the time allotted to complete an imaging experiment. Furthermore, the time course of penetration for each agent was characterized. Based on the combined imaging/penetration results, we speculate on potential sites of cholinergic action in the cortex. Irrespective of the exact mechanism of action, we demonstrate here that an increase in the size of a functional sensory representation can occur shortly by means of activation of either nicotinic or muscarinic receptors.
Collapse
Affiliation(s)
- Silke Penschuck
- Department of Neurobiology and Behavior and the Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, California 92697-4550, USA
| | | | | | | |
Collapse
|
23
|
Turégano L, Martínez-Rodríguez R, Alvarez MI, Gragera RR, Gómez de Segura A, De Miguel E, Toledano A. Histochemical study of acute and chronic intraperitoneal nicotine effects on several glycolytic and Krebs cycle dehydrogenase activities in the frontoparietal cortex and subcortical nuclei of the rat brain. J Neurosci Res 2001; 64:626-35. [PMID: 11398187 DOI: 10.1002/jnr.1116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effects of nicotine on the activity of different dehydrogenases in frontoparietal regions and subcortical nuclei of the rat brain have been studied using histochemical methods. Nicotine sulphate was intraperitoneally administered in acute (4 mg/kg/day x 3 days) or chronic (ALZET osmotic pump providing 2 mg/kg/day x 15 days) doses. The enzymes analyzed were glyceraldehyde-3-phosphate, lactate, malate and succinate dehydrogenases (gly3PDH, LDH, MDH, and SDH, respectively). The results demonstrate that chronic as well as acute administration of nicotine produced strong increases in all these enzymatic activities in the superior layers (I, II and III) of the frontoparietal cortex (cingulate, motor and somatosensory regions); but high increases were not seen in the deeper layers of the cortex or in the subcortical nuclei (substantia nigra, caudate-putamen, nucleus accumbens or nucleus basalis magnocellularis). These hyperactivities were produced in brain regions with normally low enzymatic activity (cortex), but not in those with great intensity (subcortical nuclei). The results are in rough agreement with previous reports on nicotine-induced increases in glucose utilization, gly3PDH genic expression and neuronal hyperactivity in the brain cortex; but significant discrepancies between the cortical enzymatic maps and those obtained both in these studies and others on nicotine(N)-receptor localization have been appreciated. The results support the hypothesis that nicotinic cholinergic drugs can have metabolic, long-lasting stimulant effects on cortical neurons at specific points (probably layer III pyramidal cells and structures with alpha7-N-receptors) of the cortical circuits that could be of great interest in improving altered cognitive functions that are present in Alzheimer disease, as well as in other less severe mental disturbances. Mitochondrial hyperfunction should also be evaluated as a possible side-effect (as an oxidative stress inductor) of these kinds of drugs.
Collapse
Affiliation(s)
- L Turégano
- Experimental Research Center, La Paz Hospital, INSALUD, Madrid, Spain
| | | | | | | | | | | | | |
Collapse
|
24
|
Martin-Ruiz C, Court J, Lee M, Piggott M, Johnson M, Ballard C, Kalaria R, Perry R, Perry E. Nicotinic receptors in dementia of Alzheimer, Lewy body and vascular types. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 2001; 176:34-41. [PMID: 11261803 DOI: 10.1034/j.1600-0404.2000.00305.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES Comparisons were made of nicotinic receptors in 3 major forms of dementia in old age. Although it is well established the involvement of nicotinic receptors in Alzheimer's disease (AD), their status in the other two main causes of dementia in old age-dementia with Lewy bodies (DLB) and vascular dementia (VaD) is not widely reported. METHODS Temporal cortex was examined for epibatidine and alpha-bungarotoxin binding, and immunoreactivity of alpha4 and alpha7 nAChR subunits. RESULTS There were selective abnormalities in nicotinic receptor subtypes in the disorders examined. In AD there is a loss of high affinity receptor binding, reflecting a selective loss of alpha4 subunit, but no change in alpha7 subunits. Similar abnormalities in ligand binding are also apparent in DLB. In the VaD series, there was no overall loss of epibatidine binding or immunoreactivity for alpha4 or alpha7 subunits. CONCLUSIONS Loss of cortical receptor alpha4 subunit appears to be a characteristic feature of neurodegenerative dementia but not dementia of vascular origin. Since nicotinic receptors control cerebral vasodilation, the relative integrity of the receptors in VaD may auger well for nicotinic therapy in this disorder in which there is a cholinergic abnormality, to judge by the loss of the presynaptic enzyme.
Collapse
Affiliation(s)
- C Martin-Ruiz
- Joint MRC-Newcastle University Development in Clinical Brain Aging, Newcastle General Hospital, Newcastle upon Tyne, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Elhusseiny A, Hamel E. Muscarinic--but not nicotinic--acetylcholine receptors mediate a nitric oxide-dependent dilation in brain cortical arterioles: a possible role for the M5 receptor subtype. J Cereb Blood Flow Metab 2000; 20:298-305. [PMID: 10698067 DOI: 10.1097/00004647-200002000-00011] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Increases in cortical cerebral blood flow are induced by stimulation of basal forebrain cholinergic neurons. This response is mediated in part by nitric oxide (NO) and reportedly involves both nicotinic and muscarinic receptors, some of which are possibly located in the vessel wall. In the present study, the vasomotor response(s) elicited by acetylcholine (ACh) on isolated and pressurized bovine and/or human intracortical penetrating arterioles were investigated, and pharmacological characterization of the receptor involved in this response was carried out. Acetylcholine (10(-11) to 10(-4) mol/L) dose dependently dilated bovine and human intracortical arterioles at spontaneous tone (respective pD2 values of 6.4+/-0.3 and 7.2+/-0.3 and E(Amax) of 65.0+/-26.8 and 43.2+/-30.1% of the maximal dilation obtained with papaverine) and bovine arterioles after preconstriction with serotonin (pD2 = 6.3+/-0.1, E(Amax) = 80.0+/-17.9% of induced tone). In contrast, nicotine (10(-8) to 10(-4) mol/L) failed to induce any vasomotor response in bovine vessels whether at spontaneous or at pharmacologically induced tone. Application of the nitric oxide synthase (NOS) inhibitor Nomega-nitro-L-arginine (L-NNA; 10(-5) mol/L) elicited a gradual constriction (approximately 20%) of the arterioles, indicating the presence of constitutive NO release in these vessels. Nomega-Nitro-L-argigine (10(-5) to 10(-4) mol/L) also significantly blocked the dilation induced by ACh. The muscarinic ACh receptor (mAChR) antagonists pirenzepine, 4-DAMP, and AF-DX 384 dose dependently inhibited the dilatation induced by ACh (10(-5) mol/L) with the following rank order of potency: 4-DAMP (pIC50 = 9.2+/-0.3) >> pirenzepine (pIC50 = 6.7+/-0.4) > AF-DX 384 (pIC50 = 5.9+/-0.2). These results suggest that ACh can induce a potent, dose-dependent, and NO-mediated dilation of bovine and/or human intracortical arterioles via interaction with an mAChR that best corresponds to the M5 subtype.
Collapse
Affiliation(s)
- A Elhusseiny
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Quebec, Canada
| | | |
Collapse
|
26
|
van der Zee EA, Luiten PG. Muscarinic acetylcholine receptors in the hippocampus, neocortex and amygdala: a review of immunocytochemical localization in relation to learning and memory. Prog Neurobiol 1999; 58:409-71. [PMID: 10380240 DOI: 10.1016/s0301-0082(98)00092-6] [Citation(s) in RCA: 206] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Immunocytochemical mapping studies employing the extensively used monoclonal anti-muscarinic acetylcholine receptor (mAChR) antibody M35 are reviewed. We focus on three neuronal muscarinic cholinoceptive substrates, which are target regions of the cholinergic basal forebrain system intimately involved in cognitive functions: the hippocampus; neocortex; and amygdala. The distribution and neurochemistry of mAChR-immunoreactive cells as well as behaviorally induced alterations in mAChR-immunoreactivity (ir) are described in detail. M35+ neurons are viewed as cells actively engaged in neuronal functions in which the cholinergic system is typically involved. Phosphorylation and subsequent internalization of muscarinic receptors determine the immunocytochemical outcome, and hence M35 as a tool to visualize muscarinic receptors is less suitable for detection of the entire pool of mAChRs in the central nervous system (CNS). Instead, M35 is sensitive to and capable of detecting alterations in the physiological condition of muscarinic receptors. Therefore, M35 is an excellent tool to localize alterations in cellular cholinoceptivity in the CNS. M35-ir is not only determined by acetylcholine (ACh), but by any substance that changes the phosphorylation/internalization state of the mAChR. An important consequence of this proposition is that other neurotransmitters than ACh (especially glutamate) can regulate M35-ir and the cholinoceptive state of a neuron, and hence the functional properties of a neuron. One of the primary objectives of this review is to provide a synthesis of our data and literature data on mAChR-ir. We propose a hypothesis for the role of muscarinic receptors in learning and memory in terms of modulation between learning and recall states of brain areas at the postsynaptic level as studied by way of immunocytochemistry employing the monoclonal antibody M35.
Collapse
Affiliation(s)
- E A van der Zee
- Department of Zoology, University of Groningen, Haren, The Netherlands.
| | | |
Collapse
|
27
|
Tang G, Hanna ST, Wang R. Effects of nicotine on K+ channel currents in vascular smooth muscle cells from rat tail arteries. Eur J Pharmacol 1999; 364:247-54. [PMID: 9932730 DOI: 10.1016/s0014-2999(98)00833-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intake of nicotine has been related in many cases to acute or chronic hypertension. Using the patch-clamp technique the effect of nicotine on voltage-dependent K+ channel currents in rat tail artery smooth muscle cells was studied. Nicotine at concentrations of 1-100 microM or 0.3-3 mM increased or decreased, respectively, the amplitude of the tetraethylammonium-sensitive K+ currents. Pretreatment of cells with 10 microM dihydro-beta-erythroidine hydrobromide, a nicotinic receptor antagonist, abolished the excitatory effect (n=6), but not the inhibitory effect (n=10), of nicotine on K+ channel currents. The activation of nicotinic receptors with 100 microM 1,1-dimethyl-4-phenylpiperazinium iodide increased K+ channel currents by 27.4+/-3.8% (n=13, P < 0.01). Our results indicate that the excitatory and inhibitory effects of nicotine on K+ channels are respectively mediated by a nicotinic receptor-dependent mechanism and by a direct interaction of nicotine with K+ channels.
Collapse
Affiliation(s)
- G Tang
- Department of Physiology, University of Saskatchewan, Saskatoon, Canada
| | | | | |
Collapse
|
28
|
|
29
|
Abstract
Recent immunoelectron microscopic studies have revealed a low frequency of synaptic membrane differentiations on ACh (ChAT-immunostained) axon terminals (boutons or varicosities) in adult rat cerebral cortex, hippocampus and neostriatum, suggesting that, besides synaptic transmission, diffuse transmission by ACh prevails in many regions of the CNS. Cytological analysis of the immediate micro-environment of these ACh terminals, as well as currently available immunocytochemical data on the cellular and subcellular distribution of ACh receptors, is congruent with this view. At least in brain regions densely innervated by ACh neurons, a further aspect of the diffuse transmission paradigm is envisaged: the existence of an ambient level of ACh in the extracellular space, to which all tissue elements would be permanently exposed. Recent experimental data on the various molecular forms of AChE and their presumptive role at the neuromuscular junction support this hypothesis. As in the peripheral nervous system, degradation of ACh by the prevalent G4 form of AChE in the CNS would primarily serve to keep the extrasynaptic, ambient level of ACh within physiological limits, rather than totally eliminate ACh from synaptic clefts. Long-lasting and widespread electrophysiological effects imputable to ACh in the CNS might be explained in this manner. The notions of diffuse transmission and of an ambient level of ACh in the CNS could also be of clinical relevance, in accounting for the production and nature of certain cholinergic deficits and the efficacy of substitution therapies.
Collapse
Affiliation(s)
- L Descarries
- Département de physiologie, Faculté de médecine, Université de Montréal, QC, Canada.
| | | | | |
Collapse
|
30
|
Abstract
The integrity of the cerebral vasculature is crucial to the maintenance of cognitive functions during ageing. Prevailing evidence suggests that cerebrovascular functions decline during normal ageing, with pronounced effects in Alzheimer's disease (AD). The causes of these changes largely remain unknown. While previous studies recorded ageing-related impairments, such as atherosclerosis and loss of innervation in basal surface arteries of the brain, it only recently has been realized that a number of subtle alterations in both the intracranial resistance vessels and the smaller capillaries is apparent in both ageing animals and humans. The dominant changes include alterations in composition of connective tissues and smooth muscle of large vessel walls, thickening of the vascular basement membrane, thinning of the endothelium in some species, loss of endothelial mitochondria and increased pericytes. Some of these attributes appear more affected in AD. Other abnormalities entail profound irregularities in the course of microvessels, unexplained inclusions in the basement membrane and changes in unique proteins and membrane lipids associated with the blood-brain barrier. Brain imaging and permeability studies show no clear functional evidence to support the structural and biochemical anomalies, but it is plausible that focal and transient breach of the blood-brain barrier in ageing, and more notably in AD, occurs. Thus, circumscribed neuronal populations in certain brain regions could become vulnerable. Furthermore, the characteristic deposition of amyloid in vessels in AD may exacerbate the decline in vascular function and promote chronic hypoperfusion. Although not explicit from current studies, it is likely that the brain vasculature is continually modified by growth and repair mechanisms in attempts to maintain perfusion during ageing and disease.
Collapse
Affiliation(s)
- R N Kalaria
- Department of Neurology, Case Western Reserve University School of Medicine (BRB5), Cleveland, OH 44106, USA
| |
Collapse
|
31
|
Uchida S, Kagitani F, Nakayama H, Sato A. Effect of stimulation of nicotinic cholinergic receptors on cortical cerebral blood flow and changes in the effect during aging in anesthetized rats. Neurosci Lett 1997; 228:203-6. [PMID: 9218643 DOI: 10.1016/s0304-3940(97)00401-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of intravenous injection of nicotine on cortical cerebral blood flow (CBF) was examined in urethane anesthetized rats. Nicotine (3-30 microg/kg) increased cortical CBF, independent of mean arterial pressure. This response was attenuated to about a half of the control one after lesioning the nucleus basalis of Meynert (NBM) bilaterally. The response was not significantly influenced after blocking the muscarinic receptors, but was abolished after blocking the nicotinic receptors in the parenchyma of the brain. It is concluded that the nicotine-induced cortical vasodilation was mediated by activation of the nicotinic receptors in the NBM and also in the cortex of the brain. The threshold dose of nicotine for increasing cortical CBF was shifted in aged rats of 23-26 months, and the nicotine-induced increase in cortical CBF was much reduced in aged rats of 32-36 months. Activation of nicotinic receptors in the brain may be of therapeutic value in aged subjects in facilitating the cholinergic neural vasodilative system.
Collapse
Affiliation(s)
- S Uchida
- Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Japan
| | | | | | | |
Collapse
|
32
|
Abstract
The muscarinic receptor antagonist scopolamine produces a transient memory deficit in healthy humans. This deficit has been offered as a model of the cholinergic deficit of Alzheimer's disease (AD). However, we have previously shown that scopolamine produces a deficit of cortical perfusion maximal in the frontal lobe, dissimilar to the parietal cortex deficit characteristic of AD. The current experiment was aimed at replicating and extending this observation by critically testing the central cholinergic origin of both cognitive and perfusion deficits. Nine healthy subjects participated in regional cerebral blood flow (rCBF) measurements at baseline, after scopolamine (7.2 micrograms/kg i.v.), and after both physostigmine (22 micrograms/kg i.v.) and neostigmine (7 or 11 micrograms/kg i.v.). rCBF was quantified by the xenon 133 inhalation method. As expected, scopolamine reduced cortical perfusion, mainly in the frontal cortex, and produced a memory deficit. Physostigmine, but not neostigmine, reversed all three variables partially or completely. These results support the hypothesis that all three consequences of scopolamine, namely, reduction of mean flow, frontal deficit, and memory impairment, are cholinergically mediated. Furthermore, because neostigmine poorly crosses the blood-brain barrier, these findings confirm that the effect is centrally mediated and cannot be explained by peripheral effects. However, they also confirm the frontal cortex locus of action for both scopolamine and its reversal by physostigmine and therefore suggest a major dissimilarity to the characteristic rCBF appearance of AD. This study extends our previous preliminary findings with tacrine and strengthens the suggestion that only nicotinic receptors are associated with the characteristic parietal deficit of AD.
Collapse
Affiliation(s)
- I Prohovnik
- Department of Brain Imaging, New York State Psychiatric Institute, College of Physicians and Surgeons, Columbia University, New York, USA
| | | | | | | |
Collapse
|
33
|
Luiten PG, de Jong GI, Van der Zee EA, van Dijken H. Ultrastructural localization of cholinergic muscarinic receptors in rat brain cortical capillaries. Brain Res 1996; 720:225-9. [PMID: 8782916 DOI: 10.1016/0006-8993(96)00195-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cholinergic innervation of the cerebrovasculature is known to regulate vascular tone, perfusion rate and permeability of the microvascular wall. Notably the cholinergic innervation of cerebral capillaries is of interest since these capillaries form the blood-brain barrier. Although there is a general consensus as to the presence of nicotinic and muscarinic receptors in the domain of the capillary wall, their precise anatomical position is unknown. The subcellular localization of muscarinic receptors in rat cortical capillaries was approached by way of immunocytochemistry at the ultrastructural level using monoclonal antibody M35 against muscarinic receptor protein. Binding of this antibody in the microvascular domain was found in 5% of the capillaries studied and was exclusively present in perivascular astroglia, and never in endothelium or pericytes. Combined with reported data on presynaptic cholinergic innervation the results indicate a cholinergic innervation pattern of non-directed presynaptic terminal structures in apposition to cholinoceptive perivascular astroglia with muscarinic receptor positive endfeet embracing the capillary basement membrane. The possible functional significance of such a cholinergic vascular innervation pattern is discussed with respect to capillary dynamics and barrier function.
Collapse
Affiliation(s)
- P G Luiten
- Department of Animal Physiology, University of Groningen, Haren, Netherlands
| | | | | | | |
Collapse
|