1
|
Maruyama T, Mano A, Ishii T, Kakinuma Y, Kaneda M. P2X 2 receptors supply extracellular choline as a substrate for acetylcholine synthesis. FEBS Open Bio 2021; 12:250-257. [PMID: 34787962 PMCID: PMC8727932 DOI: 10.1002/2211-5463.13332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/03/2021] [Accepted: 11/16/2021] [Indexed: 01/14/2023] Open
Abstract
Acetylcholine (ACh), an excitatory neurotransmitter, is biosynthesized from choline in cholinergic neurons. Import from the extracellular space to the intracellular environment through the high-affinity choline transporter is currently regarded to be the only source of choline for ACh synthesis. We recently demonstrated that the P2X2 receptor, through which large cations permeate, functions as an alternative pathway for choline transport in the mouse retina. In the present study, we investigated whether choline entering cells through P2X2 receptors is used for ACh synthesis using a recombinant system. When P2X2 receptors expressed on HEK293 cell lines were stimulated with ATP, intracellular ACh concentrations increased. These results suggest that P2X2 receptors function in a novel pathway that supplies choline for ACh synthesis.
Collapse
Affiliation(s)
- Takuma Maruyama
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Asuka Mano
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Toshiyuki Ishii
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | | | - Makoto Kaneda
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| |
Collapse
|
2
|
Mactier RA, Khanna R, Twardowski ZJ, Moore H, Nolph KD. Influence of Phosphatidylcholine on Lymphatic Absorption during Peritoneal Dialysis in the Rat. Perit Dial Int 2020. [DOI: 10.1177/089686088800800301] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The mechanism whereby i.p. administration of phosphatidylcholine increases net ultrafiltration and solute clearances after long-dwell exchanges is not established. We performed 4-h exchanges in rats using 4.25% dextrose dialysis solution with and without the addition of 50 mgl L phosphatidylcholine. Net ultrafiltration was enhanced in the treated rats (p < 0.005) by a reduction in cumulative lymphatic absorption (p < 0.01) and without a concurrent increase in total net transcapillary ultrafiltration during the dwell time. Likewise, urea and phosphate clearances with i.p. phosphatidylcholine were enhanced mainly by the increase in the drain volume since serum to dialysate solute concentration ratios did not differ significantly between the treated and control rats. Thus, phosphatidylcholine increases net ultrafiltration and solute clearances in the rat by decreasing lymphatic absorption and without increasing transperitoneal transport of water and solutes into the peritoneal cavity. The uptake of the india ink by the lymphatics of rats who received dialysis exchanges without phosphatidylcholine and the lack of uptake in rats treated with phosphatidylcholine are supported by this observation. Reduction in lymphatic absorption with the addition of phosphatidylcholine to the infused dialysis solution offers an alternative means of enhancing the efficiency of long-dwell peritoneal dialysis.
Collapse
Affiliation(s)
- Robert A. Mactier
- Division of Nephrology, Department of Medicine, University of Missouri Health Sciences Center, Dalton Research Center, and Harry S. Truman V.A. Hospital, Columbia, Missouri
| | - Ramesh Khanna
- Division of Nephrology, Department of Medicine, University of Missouri Health Sciences Center, Dalton Research Center, and Harry S. Truman V.A. Hospital, Columbia, Missouri
| | - Zbylut J. Twardowski
- Division of Nephrology, Department of Medicine, University of Missouri Health Sciences Center, Dalton Research Center, and Harry S. Truman V.A. Hospital, Columbia, Missouri
| | - Harold Moore
- Division of Nephrology, Department of Medicine, University of Missouri Health Sciences Center, Dalton Research Center, and Harry S. Truman V.A. Hospital, Columbia, Missouri
| | - Karl D. Nolph
- Division of Nephrology, Department of Medicine, University of Missouri Health Sciences Center, Dalton Research Center, and Harry S. Truman V.A. Hospital, Columbia, Missouri
| |
Collapse
|
3
|
Mitra S, Behbahani H, Eriksdotter M. Innovative Therapy for Alzheimer's Disease-With Focus on Biodelivery of NGF. Front Neurosci 2019; 13:38. [PMID: 30804738 PMCID: PMC6370742 DOI: 10.3389/fnins.2019.00038] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 01/15/2019] [Indexed: 12/31/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with abnormal protein modification, inflammation and memory impairment. Aggregated amyloid beta (Aβ) and phosphorylated tau proteins are medical diagnostic features. Loss of memory in AD has been associated with central cholinergic dysfunction in basal forebrain, from where the cholinergic circuitry projects to cerebral cortex and hippocampus. Various reports link AD progression with declining activity of cholinergic neurons in basal forebrain. The neurotrophic molecule, nerve growth factor (NGF), plays a major role in the maintenance of cholinergic neurons integrity and function, both during development and adulthood. Numerous studies have also shown that NGF contributes to the survival and regeneration of neurons during aging and in age-related diseases such as AD. Changes in neurotrophic signaling pathways are involved in the aging process and contribute to cholinergic and cognitive decline as observed in AD. Further, gradual dysregulation of neurotrophic factors like NGF and brain derived neurotrophic factor (BDNF) have been reported during AD development thus intensifying further research in targeting these factors as disease modifying therapies against AD. Today, there is no cure available for AD and the effects of the symptomatic treatment like cholinesterase inhibitors (ChEIs) and memantine are transient and moderate. Although many AD treatment studies are being carried out, there has not been any breakthrough and new therapies are thus highly needed. Long-term effective therapy for alleviating cognitive impairment is a major unmet need. Discussion and summarizing the new advancements of using NGF as a potential therapeutic implication in AD are important. In summary, the intent of this review is describing available experimental and clinical data related to AD therapy, priming to gain additional facts associated with the importance of NGF for AD treatment, and encapsulated cell biodelivery (ECB) as an efficient tool for NGF delivery.
Collapse
Affiliation(s)
- Sumonto Mitra
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden
| | - Homira Behbahani
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Maria Eriksdotter
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.,Aging Theme, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
4
|
Lee KU, Lee JH, Lee DY, Youn JC, Kim JL, Moon SW, Kim BJ, Ryu SH, Kim MD, Lee CU, Lee NJ, Chang SM, Kim YH, Kim DH, Lee HK, Woo JI, Kim KW, Jhoo JH. The Effect of Choline Acetyltransferase Genotype on Donepezil Treatment Response in Patients with Alzheimer's Disease. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2015; 13:168-73. [PMID: 26243844 PMCID: PMC4540042 DOI: 10.9758/cpn.2015.13.2.168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 02/23/2015] [Accepted: 02/24/2015] [Indexed: 12/26/2022]
Abstract
Objective We examined the difference in responses to donepezil between carriers and non-carriers of the A allele at the +4 position of the choline acetyltransferase (ChAT) gene in Koreans. Methods Patients who met the criteria for probable Alzheimer’s disease (AD) (n=199) were recruited. Among these, 145 completed the 12-week follow-up evaluation and 135 completed the 26-week scheduled course. Differences and changes in the Korean version of the mini-mental state examination (MMSE-KC) score, Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease Neuropsychological Assessment Battery (CERAD-K[N]) wordlist subtest score (WSS), CERAD-K(N) total score (TS), and the Korean version of geriatric depression scale (GDS-K) score between baseline and 12 weeks or 26 weeks were assessed by the Student’s t-test. Results At 12 weeks, the changes in the MMSE-KC score, CERAD-K(N) WSS, and CERAD-K(N) TS from baseline were not significant between ChAT A allele carriers and non-carriers; however, at 26 weeks, these changes were significantly larger in ChAT A allele carriers than in non-carriers (p=0.02 for MMSE-KC and p=0.03 for CERAD-K(N) WSS respectively). Conclusion Our findings in this study suggested that presence of the A allele at the +4 position of ChAT might positively influence the treatment effect of donepezil in the early stages of AD in Koreans.
Collapse
Affiliation(s)
- Kang Uk Lee
- Department of Psychiatry, Kangwon National University School of Medicine, Chuncheon, Korea
| | - Jung Hie Lee
- Department of Psychiatry, Kangwon National University School of Medicine, Chuncheon, Korea
| | - Dong Young Lee
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea.,Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Jong Chul Youn
- Department of Neuropsychiatry, Kyunggi Provincial Hospital for the Elderly, Yongin, Korea
| | - Jeong Lan Kim
- Department of Psychiatry, Chungnam National University Hospital, Daejeon, Korea
| | - Seok Woo Moon
- Department of Psychiatry, Konkuk University Chungju Hospital, Chungju, Korea
| | - Bong-Jo Kim
- Department of Psychiatry, Gyeongsang National University Hospital, Jinju, Korea
| | - Seung-Ho Ryu
- Department of Neuropsychiatry, Konkuk University Hospital, Seoul, Korea
| | - Moon Doo Kim
- Department of Neuropsychiatry, Jeju National University Hospital, Jeju, Korea
| | - Chang-Uk Lee
- Department of Psychiatry, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Nam-Jin Lee
- Department of Psychiatry, Jeonju City Welfare Hospital for the Elderly, Jeonju, Korea
| | - Sung Man Chang
- Department of Psychiatry, Kyungbook National University Hospital, Daegu, Korea
| | - Young Hoon Kim
- Department of Psychiatry, Haeundae Paik Hospital, Busan, Korea
| | - Do Hoon Kim
- Department of Psychiatry, Chuncheon Sacred Hospital, Chuncheon, Korea
| | - Hae-Kook Lee
- Department of Psychiatry, Uijeongbu St. Mary's Hospital, Uijeongbu, Korea
| | - Jong Inn Woo
- Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Ki Woong Kim
- Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea.,Department of Brain and Cognitive Science, Seoul National University College of Natural Sciences, Seoul, Korea.,Department of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jin Hyeong Jhoo
- Department of Psychiatry, Kangwon National University School of Medicine, Chuncheon, Korea
| |
Collapse
|
5
|
Effects of chronic social defeat stress on behaviour, endoplasmic reticulum proteins and choline acetyltransferase in adolescent mice. Int J Neuropsychopharmacol 2013; 16:1635-47. [PMID: 23442729 DOI: 10.1017/s1461145713000060] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The present study investigated the effects of social defeat stress on the behaviours and expressions of 78-kDa glucose-regulated protein (Grp78), CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) and choline acetyltransferase (Chat) in the brains of adolescent mice. Adolescent male C57BL/6J mice were divided into two groups (susceptible and unsusceptible) after 10 d social defeat stress. In expt 1, behavioural tests were conducted and brains were processed for Western blotting on day 21 after stress. In expt 2, social avoidance tests were conducted and brains were subsequently processed for Western blotting on day 12 after stress. Chronic social defeat stress produced more pronounced depression-like behaviours such as decreased locomotion and social interaction, increased anxiety-like behaviours and immobility, and impaired memory performance in susceptible mice. Moreover, susceptible mice showed greater expression of Grp78 and CHOP in the amygdala (Amyg) on days 12 and 21 compared with the other groups. Susceptible and unsusceptible groups showed significant increases in Grp78 and CHOP expression in the prefrontal cortex (PFC) and hippocampus (Hipp) on day 12 compared with the control group; this persisted until day 21. The levels of Chat measured on days 12 and 21 were significantly lower in the PFC, Amyg and Hipp of all defeated mice compared with controls. The findings of the behavioural tests indicate that chronic social defeat in adolescents produces anxiety-like behaviours, social withdrawal, despair-like behaviours and cognitive impairment. The Grp78, CHOP and Chat results suggest that the selective response of endoplasmic reticulum stress proteins in the Amyg plays an important role in the vulnerability-stress model of depression.
Collapse
|
6
|
Zhao T, Huang GB, Muna SS, Bagalkot TR, Jin HM, Chae HJ, Chung YC. Effects of chronic social defeat stress on behavior and choline acetyltransferase, 78-kDa glucose-regulated protein, and CCAAT/enhancer-binding protein (C/EBP) homologous protein in adult mice. Psychopharmacology (Berl) 2013; 228:217-30. [PMID: 23468099 DOI: 10.1007/s00213-013-3028-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 02/05/2013] [Indexed: 11/28/2022]
Abstract
RATIONALE Social defeat stress induces physiological and behavioral symptoms, including anxiety, anhedonia, immune deficits, and altered expression of key brain genes. OBJECTIVES The present study investigated the effects of social defeat stress on the behaviors and expressions of Chat, Grp78, and chop in the brains of adult mice. METHODS Adult mice were divided into susceptible and unsusceptible groups after 10 days of social defeat stress. In experiment 1, behavioral tests were conducted, and brains were processed for Western blotting at day 27 after stress. In experiment 2, social avoidance tests were conducted, and brains were processed for Western blotting at day 12 after stress. RESULTS The results indicate decreased and increased locomotion and anxiety behavior in all defeated mice. Decrease in social interaction, increased immobility, and impaired memory performance were only observed in susceptible mice. A decrease in the Chat level at days 12 and 27 was noted in the prefrontal cortex (PFC), amygdala (Amyg), and dorsal hippocampus (HIP) in defeated mice. The expression levels of Grp78 and chop measured on days 12 and 27 were significantly greater in the Amyg of susceptible mice. In the PFC and HIP, defeated mice displayed different patterns in the levels of Grp78 and chop expressions measured on days 12 and 27. CONCLUSIONS The present study demonstrated that chronic social defeat stress in mice produces stress-related behaviors. Different response patterns were noted for Grp78 and chop expression among the groups in terms of brain regions and time-course effects.
Collapse
Affiliation(s)
- Tong Zhao
- Department of Psychiatry, Chonbuk National University Medical School, Jeonju, Korea
| | | | | | | | | | | | | |
Collapse
|
7
|
Choline acetyltransferase 2384G>a polymorphism and the risk of Alzheimer disease. Alzheimer Dis Assoc Disord 2012; 26:81-7. [PMID: 21602657 DOI: 10.1097/wad.0b013e31821cbcaf] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The potential association between choline acetyltransferase (CHAT) polymorphism and the risk of Alzheimer disease (AD) has been controversial. We examined the main effect of CHAT polymorphism and its interaction with apolipoprotein E (APOE) polymorphism in the development of AD in a well-powered elderly Korean sample. We analyzed CHAT 2384G>A polymorphism and APOE polymorphism among 736 Korean patients with probable AD and 1386 nondemented Korean controls. We tested the association between AD and CHAT genotype using a logistic regression model. In addition, we used generalized multifactor dimensionality reduction to investigate the interaction between CHAT and APOE with regard to the risk of AD. The CHAT A allele was associated with AD risk in a dose-dependent manner (odds ratio=1.40, 95% confidence interval=1.06-1.85, P=0.018 for heterozygotes; and odds ratio=3.92, 95% confidence interval=1.78-8.58, P=0.001 for homozygotes). The generalized multifactor dimensionality reduction approach identified a significant gene-gene interaction between CHAT and APOE (Balanced accuracy score=0.647, P=0.001). The CHAT A/A genotype was associated with earlier onset of AD (F=5.070, df=2, P=0.007). The CHAT A allele was associated with AD risk in a dose-dependent manner, and its interaction with the APOE ε4 allele was significant with regard to the development of AD. The CHAT A allele was also associated with earlier onset and possibly accelerated progression of AD.
Collapse
|
8
|
Halappa R, David M. In Vivo Inhibition of Acetylcholinesterase Activity in Functionally Different Tissues of the Freshwater Fish, Cyprinus carpio, Under Chlorpyrifos Exposure. ACTA ACUST UNITED AC 2009; 24:123-36. [DOI: 10.1515/dmdi.2009.24.2-4.123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
9
|
Hartmann J, Kiewert C, Duysen EG, Lockridge O, Greig NH, Klein J. Excessive hippocampal acetylcholine levels in acetylcholinesterase-deficient mice are moderated by butyrylcholinesterase activity. J Neurochem 2006; 100:1421-9. [PMID: 17212694 DOI: 10.1111/j.1471-4159.2006.04347.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Central cholinergic systems are involved in a plethora of brain functions and are severely and selectively damaged in neurodegenerative diseases such as Alzheimer's disease and dementia with Lewy bodies. Cholinergic dysfunction is treated with inhibitors of acetylcholinesterase (AChE) while the role of butyrylcholinesterase (BChE) for brain cholinergic function is unclear. We have used in vivo microdialysis to investigate the regulation of hippocampal acetylcholine (ACh) levels in mice that are devoid of AChE (AChE-/- mice). Extracellular ACh levels in the hippocampus were 60-fold elevated in AChE-/- mice compared with wild-type (AChE+/+) animals. In AChE-/- mice, calcium-free conditions reduced hippocampal ACh levels by 50%, and infusion of tetrodotoxin by more than 90%, indicating continuous ACh release. Infusion of a selective AChE inhibitor (BW284c51) caused a dose-dependent, up to 16-fold increase of extracellular ACh levels in AChE+/+ mice but did not change ACh levels in AChE-/- mice. In contrast, infusion of a selective inhibitor of BChE (bambuterol) caused up to fivefold elevation of ACh levels in AChE-/- mice, but was without effect in AChE+/+ animals. These results were corroborated with two other specific inhibitors of AChE and BChE, tolserine and bis-norcymserine, respectively. We conclude that lack of AChE causes dramatically increased levels of extracellular ACh in the brain. Importantly, in the absence of AChE, the levels of extracellular ACh in the brain are controlled by the activity of BChE. These results point to a potential usefulness of BChE inhibitors in the treatment of central cholinergic dysfunction in which brain AChE activity is typically reduced.
Collapse
Affiliation(s)
- Joachim Hartmann
- Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Science Center, Amarillo, Texas 79106, USA
| | | | | | | | | | | |
Collapse
|
10
|
|
11
|
Meck WH. Temporal memory in mature and aged rats is sensitive to choline acetyltransferase inhibition. Brain Res 2006; 1108:168-75. [PMID: 16854393 DOI: 10.1016/j.brainres.2006.06.047] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 06/09/2006] [Accepted: 06/09/2006] [Indexed: 11/24/2022]
Abstract
The effects of a potent inhibitor of choline acetyltransferase (ChAT), BW813U, on timing behavior in mature (6-10 months) and aged (26-30 months) male rats were assessed. Twenty rats were trained on a discrete trial 20-s peak-interval (PI) procedure. During baseline (non-drug) training, the time of the maximum response rate (peak time) for mature rats was approximately at the time of scheduled reinforcement, but peak time for aged rats was reliably later. A single administration of BW813U (100 mg/kg, ip) produced a long-lasting increase in peak time for both mature and aged rats that occurred gradually and was synergistic with age. These horizontal shifts in peak time indicate a change in the content of reference memory for the remembered time of reinforcement that is similar for both aging processes and BW813U administration. When a 5-s gap was imposed in the signal, PI-GAP procedure, control rats of both ages summed the signal durations before and after the gap, whereas rats given BW813U showed no retention of the signal duration prior to the gap. This loss of trial-specific temporal information suggests a drug-induced working memory dysfunction. Taken together, these results demonstrate that both working and reference memory for temporal information are sensitive to choline acetyltransferase inhibition in rats.
Collapse
Affiliation(s)
- Warren H Meck
- Department of Psychology and Neuroscience, Duke University, 572 Research Drive, Genome Sciences Research Building II-Box 91050, Durham, NC 27708, USA.
| |
Collapse
|
12
|
Kim KW, Suh YJ, Park WY, Jhoo JH, Lee DY, Youn JC, Lee KH, Seo JS, Woo JI. Choline acetyltransferase G +4 A polymorphism confers a risk for Alzheimer’s disease in concert with Apolipoprotein E ε4. Neurosci Lett 2004; 366:182-6. [PMID: 15276243 DOI: 10.1016/j.neulet.2004.05.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2004] [Revised: 04/20/2004] [Accepted: 05/15/2004] [Indexed: 10/26/2022]
Abstract
To examine whether the single nucleotide polymorphism at position +4 of the choline acetyltransferase (ChAT) confers a risk for Alzheimer's disease (AD), we determined the ChAT and the Apolipoprotein (APOE) genotypes of the 246 AD patients and 561 non-demented controls. The ChAT AA genotype was found to confer the risk for AD in concert with the APOE epsilon4 by stochastic search variable selection (SSVS) approach. The odds of the ChAT AA for AD were 3.25 (95% CI = 1.17-9.03). The mean ages-at-onset of AD were lower in those carrying the ChAT AA than those carrying the ChAT AG or ChAT GG, regardless to the occurrence of the APOE epsilon4. The ChAT AA is a novel genetic risk factor AD, and the SSVS is a useful approach for analyzing association with multiple candidate genes simultaneously.
Collapse
Affiliation(s)
- Ki-Woong Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, Kyunggi-do, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Abstract
Choline has many physiological functions throughout the body that are dependent on its available local supply. However, since choline is a charged hydrophilic cation, transport mechanisms are required for it to cross biological membranes. Choline transport is required for cellular membrane construction and is the rate-limiting step for acetylcholine production. Transport mechanisms include: (1) sodium-dependent high-affinity uptake mechanism in synaptosomes, (2) sodium-independent low-affinity mechanism on cellular membranes, and (3) unique choline uptake mechanisms (e.g., blood-brain barrier choline transport). A comprehensive overview of choline transport studies is provided. This review article examines landmark and current choline transport studies, molecular mapping, and molecular identification of these carriers. Information regarding the choline-binding site is presented by reviewing choline structural analog (hemicholinium-3 and 15, and other nitrogen/methyl-hydroxyl compounds) inhibition studies. Choline transport in Alzheimer's disease, brain ischemic events, and aging is also discussed. Emphasis throughout the article is placed on targeting the choline transporter in disease and use of this carrier as a drug delivery vector.
Collapse
Affiliation(s)
- P R Lockman
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas 79106-1712, USA
| | | |
Collapse
|
14
|
Savci V, Goktalay G, Ulus IH. Intracerebroventricular choline increases plasma vasopressin and augments plasma vasopressin response to osmotic stimulation and hemorrhage. Brain Res 2002; 942:58-70. [PMID: 12031853 DOI: 10.1016/s0006-8993(02)02692-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Intracerebroventricular (i.c.v.) injection of choline (50-150 microg), a precursor of the neurotransmitter acetylcholine, produced a time-and dose-dependent increase in plasma vasopressin levels in conscious, freely moving rats. The increase in plasma vasopressin in response to i.c.v. choline (150 microg) was inhibited by pretreatment with the nicotinic receptor antagonist, mecamylamine (50 microg; i.c.v.), but not by the muscarinic receptor antagonist, atropine (10 microg; i.c.v). The choline-induced rise in plasma vasopressin levels was greatly attenuated by hemicholinium-3 (HC-3; 20 microg; i.c.v.), a neuronal choline uptake inhibitor. Choline (50 or 150 microg; i.c.v.) produced a much greater increase in plasma vasopressin levels in osmotically stimulated or hemorrhaged rats than in normal rats. Choline (150 microg; i.c.v.) also enhanced plasma vasopressin response to graded hemorrhage; the enhancing effect of choline was also attenuated by HC-3 (20 microg; i.c.v.). Choline and acetylcholine concentrations in hypothalamic dialysates increased significantly following i.c.v. injection of choline (150 microg). It is concluded that choline increases plasma vasopressin levels by stimulating central nicotinic receptors indirectly, through the enhancement of acetylcholine synthesis and release, and augments the ability of osmotic stimulations or hemorrhage to stimulate vasopressin release.
Collapse
Affiliation(s)
- Vahide Savci
- Department of Pharmacology and Clinical Pharmacology, Uludag University Medical School, Bursa, Turkey
| | | | | |
Collapse
|
15
|
Bartus RT. On neurodegenerative diseases, models, and treatment strategies: lessons learned and lessons forgotten a generation following the cholinergic hypothesis. Exp Neurol 2000; 163:495-529. [PMID: 10833325 DOI: 10.1006/exnr.2000.7397] [Citation(s) in RCA: 552] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Life's Journey If life is indeed a journey, then poetry must be the map that reveals all its topographic possibilitiesellipsis while science is the compass that keeps us from getting lost. -R. T. Bartus, Simple Words for Complex Lives, (c) 1998 In the nearly 20 years since the cholinergic hypothesis was initially formulated, significant progress has been achieved. Initial palliative treatments for Alzheimer's disease (AD) have proven beneficial and have gained FDA approval, the use of animal models for studying AD and other neurodegenerative diseases has achieved wider acceptance, and important insight into the potential causes and pathogenic variables associated with various neurodegenerative diseases continues to increase. This paper reviews the current status of the cholinergic hypothesis in the context of continuing efforts to improve upon existing treatments for AD and explores the role that animal models might continue to play. Using the benefit of hindsight, particular emphasis is placed on an analysis of the approaches, strategies, and assumptions regarding animal models that proved useful in developing the initial treatments and those that did not. Additionally, contemporary issues of AD are discussed within the context of the cholinergic hypothesis, with particular attention given to how they may impact the further refinement of animal models, and the development of even more effective treatments. Finally, arguments are presented that, despite the deserved enthusiasm and optimism for identifying means of halting the pathogenesis of AD, a clear need for more effective palliative treatments will continue, long after successful pathogenic treatments are available. This review, therefore, focuses on issues and experiences intended to: (a) facilitate further development and use of animal models for AD and other neurodegenerative diseases, and (b) accelerate the identification of newer, even more effective treatments.
Collapse
Affiliation(s)
- R T Bartus
- Preclinical R&D, Alkermes, Inc., 64 Sidney Street, Cambridge, Massachusetts 02139, USA
| |
Collapse
|
16
|
Gürün MS, Savci V, Ulus IH, Kiran BK. Centrally administered choline increases plasma prolactin levels in conscious rats. Neurosci Lett 1997; 232:79-82. [PMID: 9302091 DOI: 10.1016/s0304-3940(97)00580-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Intracerebroventricular (i.c.v.) administration of choline, a precursor of acetylcholine (ACh) increased plasma prolactin levels in a time and dose-dependent manner in conscious rats. Pretreatment of rats with the cholinergic muscarinic antagonist, atropine (10 microg, i.c.v.), blocked the increase in plasma prolactin level. The increase was not influenced by pretreatment with the cholinergic nicotinic antagonist, mecamylamine (50 microg, i.c.v.). Pretreatment with hemicholinium-3 (HC-3; 20 microg, i.c.v.), a high affinity choline uptake inhibitor, attenuated the choline-induced increase of plasma prolactin levels. These results show that choline increases plasma prolactin levels by activating muscarinic receptors via presynaptic mechanisms.
Collapse
Affiliation(s)
- M S Gürün
- Department of Pharmacology, Uludag University Medical Faculty, Bursa, Turkey
| | | | | | | |
Collapse
|
17
|
Kobayashi H, Suzuki T, Kasashima Y, Motegi A, Sato I, Matsusaka N, Ono N, Miura A, Saito F, Saito S. Effects of tri-, di- and monobutyltin on synaptic parameters of the cholinergic system in the cerebral cortex of mice. JAPANESE JOURNAL OF PHARMACOLOGY 1996; 72:317-24. [PMID: 9015740 DOI: 10.1254/jjp.72.317] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Triorganotin compounds like tributyltin have been reported to be biodegraded to diorganotin, monoorganotin and then inorganic tin in animals after they have been ingested. Effects of tributyltin, dibutyltin and monobutyltin on various cholinergic parameters that are involved in synaptic transmission in the mouse cerebral cortex were investigated in vitro. Tributyltin and dibutyltin, but not monobutyltin, inhibited the activity of choline acetyltransferase, both the high-affinity and low-affinity uptakes of choline into synaptosomes, and the binding of [3H]quinuclidinyl benzilate to muscarinic acetylcholine receptors. Tributyltin and dibutyltin, but not monobutyltin, had a slightly suppressive effect on the K(+)-induced release and synthesis of acetylcholine in slices of the cortex. All three butyltins at concentrations from 10(-6) to 10(-4) M had no effect on the activity of acetylcholinesterase. The extent of the inhibitory effects on the cholinergic parameters, apart from the activity of acetylcholinesterase, was slightly greater in the case of tributyltin than dibutyltin, in particularly at the highest concentration (10(-4) M) tested. Therefore, it is concluded that tributyltin metabolites inhibit various parameters of cholinergic activity with a potency ranking of tributyltin > dibutyltin > monobutyltin.
Collapse
Affiliation(s)
- H Kobayashi
- Department of Veterinary Pharmacology, Faculty of Agriculture, Iwate University, Morioka, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Rossner S, Yu J, Pizzo D, Werrbach-Perez K, Schliebs R, Bigl V, Perez-Polo JR. Effects of intraventricular transplantation of NGF-secreting cells on cholinergic basal forebrain neurons after partial immunolesion. J Neurosci Res 1996; 45:40-56. [PMID: 8811511 DOI: 10.1002/(sici)1097-4547(19960701)45:1<40::aid-jnr4>3.0.co;2-h] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The aim of the present study was to examine the effects of nerve growth factor on brain cholinergic function after a partial immunolesion to the rat cholinergic basal forebrain neurons (CBFNs) by 192 IgG-saporin. Two weeks after intraventricular injections of 1.3 micrograms of 192 IgG-saporin, about 50% of CBFNs were lost which was associated with 40-60% reductions of choline acetyltransferase (ChAT) and high-affinity choline uptake (HACU) activities throughout the basal forebrain cholinergic system. Two groups of lesioned animals received intraventricular transplantations of mouse 3T3 fibroblasts retrovirally transfected with either the rat NGF gene (3T3NGF+) or the retrovirus alone (3T3NGF-) and were sacrificed eight weeks later. In vivo production of NGF by 3T3NGF+ cells was confirmed by NGF immunohistochemistry on the grafts and NGF immunoassay on cerebrospinal fluid (CSF) samples. Both ChAT and HACU activities returned to normal control levels in the basal forebrain and cortex after 3T3NGF+ transplants, whereas no recovery was observed in 3T3NGF- transplanted animals. There was a 25% increase in the size of remaining CBFNs and an increased staining intensity for NGF immunoreactivity in these cells after NGF treatments. Acetylcholinesterase (AChE) histochemistry revealed that the optical density of AChE-positive fibers in the cerebral cortex and hippocampus were reduced by about 60% in immunolesioned rats which were completely restored by 3T3NGF+ grafts. In addition, decreases in growth-associated protein (GAP)-43 immunoreactivity after immunolesion and increases in synaptophysin immunoreactivity after 3T3NGF+ grafts were observed in the hippocampus. Our results further confirm the notion that transfected NGF-secreting cells are useful in long-term in vivo NGF treatment and NGF can upregulate CBFN function. They also highly suggest that NGF induces terminal sprouting from remaining CBFNs.
Collapse
Affiliation(s)
- S Rossner
- Paul Flechsig Institute for Brain Research, Department of Neurochemistry, University of Leipzig, Medical Faculty, Germany
| | | | | | | | | | | | | |
Collapse
|
19
|
Fitzgerald RS, Shirahata M, Ishizawa Y. The presynaptic component of a cholinergic mechanism in the carotid body chemotransduction of hypoxia in the cat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1996; 410:245-52. [PMID: 9030306 DOI: 10.1007/978-1-4615-5891-0_36] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- R S Fitzgerald
- Department of Environmental Health Sciences, Johns Hopkins Medical Institution's, Baltimore, Maryland 21205, USA
| | | | | |
Collapse
|
20
|
Affiliation(s)
- I Zs-Nagy
- Fritz Verzár International Laboratory for Experimental Gerontology (VILEG), University Medical School, Debrecen, Hungary
| |
Collapse
|
21
|
Marshall DL, Wurtman RJ. Effect of choline on basal and stimulated acetylcholine release: an in vivo microdialysis study using a low neostigmine concentration. Brain Res 1993; 629:269-74. [PMID: 8111630 DOI: 10.1016/0006-8993(93)91330-u] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Using in vivo microdialysis, we examined the ability of choline (Ch) chloride (120 mg/kg i.p.) to amplify basal and stimulated acetylcholine (ACh) release from rat striatum in the presence of high (10(-5) M) and low (5 x 10(-8) M) neostigmine concentration. High concentrations might suppress ACh release, and thus Ch dependence, by excessively stimulating presynaptic cholinergic receptors; alternatively, they could enhance Ch dependence by depriving the cholinergic terminals of Ch that would otherwise be formed intrasynaptically from the hydrolysis of ACh. Both basal and stimulated ACh release were found to be tetrodotoxin (TTX) sensitive. The concentration of neostigmine in the microdialysis fluid positively affected basal ACh levels, but had no effect on Ch levels. Ch administration significantly increased ACh release (to 136% of basal values; P < 0.01) in the presence of the low neostigmine concentration, but failed to significantly increase ACh release following local electrical depolarization of striatal neurons. In contrast, Ch failed to affect basal ACh release in the presence of the high neostigmine concentration, but did increase electrically evoked release to 408% of basal values, as compared with 250% in rats receiving saline instead of the Ch (P < 0.05). Ch administration significantly increased microdialysate Ch levels in the presence of both of the neostigmine concentrations. Local administration of oxotremorine, a muscarinic agonist, to animals receiving the lower neostigmine concentration reduced basal ACh release and reduced the increase in basal release produced by Ch administration.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- D L Marshall
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139
| | | |
Collapse
|
22
|
Ishimaru H, Ikarashi Y, Takahashi A, Maruyama Y. Acute neurochemical changes in mouse brain following cerebral ischemia. Eur Neuropsychopharmacol 1993; 3:485-91. [PMID: 8111221 DOI: 10.1016/0924-977x(93)90273-o] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Acute changes in neurochemical levels induced by ischemia were studied in the mouse brain. Contents of neurochemicals in the frontal, parietal and occipital cortices and hippocampus were determined immediately after 15 min of ischemia (0), and then at 15, 30, 90 and 180 min after recirculation following ischemia. These data were compared with those for sham-operated control mice. Choline (Ch) contents in ischemic animals increased by 530-630% from control levels immediately after ischemia, and returned to control levels by 90 min. Decreases in levels of norepinephrine (NE) and serotonin (5-HT) were observed during 30 min after recirculation. There were no significant changes in levels of acetylcholine (ACh) or dopamine (DA), throughout recirculation. On the other hand, DA and 5-HT metabolites (3,4-dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid) significantly increased. Thus, comprehensively investigating the various neurotransmitters will provide meaningful information regarding the disturbance of central nervous system induced by cerebrovascular disease.
Collapse
Affiliation(s)
- H Ishimaru
- Department of Neuropsychopharmacology (Tsumara), Gunma University, School of Medicine, Japan
| | | | | | | |
Collapse
|
23
|
Bertrand N, Ishii H, Beley A, Spatz M. Biphasic striatal acetylcholine release during and after transient cerebral ischemia in gerbils. J Cereb Blood Flow Metab 1993; 13:789-95. [PMID: 8360285 DOI: 10.1038/jcbfm.1993.100] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Acetylcholine (ACh) release into the extracellular space was measured by HPLC with electrochemical detection after in vivo intracerebral microdialysis in the striatum of gerbils subjected to 15 min of bilateral carotid artery occlusion followed by 5 h of recirculation. Tissue ACh and choline (Ch) contents were also determined during ischemia and after 5, 30, 60, and 120 min of reflow. Fifteen minutes of ischemia led to a significant transient increase in extracellular ACh concentration (threefold after 7.5 min of ischemia) concomitant with a reduced endogenous ACh level (-62%) and increased tissue Ch content (ninefold). Recirculation significantly reduced the ACh release during the early period of reflow (-50% vs. basal level), followed by a significant increase in ACh release between 1 and 3 h of reflow (45-55% vs. basal level) and subsequent normalization. Simultaneously, a "rebound" of tissue ACh level occurred in the early period of reflow (fourfold vs. ischemic value), followed by gradual normalization after 2 h of reperfusion, whereas a rapid decrease in tissue Ch levels was found after 30 min of reflow. These findings represent the first demonstration of a biphasic release of ACh during ischemia and reperfusion, as assessed by intracerebral microdialysis in gerbils.
Collapse
Affiliation(s)
- N Bertrand
- Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
| | | | | | | |
Collapse
|
24
|
Bostwick JR, Abbe R, Appel SH. Phosphoethanolamine enhances high-affinity choline uptake and acetylcholine synthesis in dissociated cell cultures of the rat septal nucleus. J Neurochem 1992; 59:236-44. [PMID: 1613501 DOI: 10.1111/j.1471-4159.1992.tb08896.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Dissociated rat septal nucleus cells cultured in defined medium exhibited twofold increases in the maximal rates of sodium-dependent, high-affinity choline uptake and acetylcholine formation when grown in the presence of phosphoethanolamine. The effect was concentration-dependent (EC50 = 15 microM) and appeared to be associated with in vitro maturation of cholinergic neurons rather than with enhanced survival. Choline acetyltransferase, acetylcholinesterase, and choline kinase activities were unaffected by this treatment. The effect of phosphoethanolamine was specific for cholinergic neurons, because treatment with this compound did not alter the kinetic constants for high-affinity neuronal uptake of gamma-aminobutyric acid or dopamine. The action appeared to be mediated primarily through activation of the sodium-dependent, high-affinity transport mechanism for choline as opposed to alterations in the storage and release of acetylcholine.
Collapse
Affiliation(s)
- J R Bostwick
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | | | | |
Collapse
|
25
|
Kobayashi H, Saito F, Yuyama A. Effects of organotins on the cholinergic system in the chicken brain in vitro. Toxicol In Vitro 1992; 6:337-43. [DOI: 10.1016/0887-2333(92)90023-k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/1991] [Revised: 01/23/1992] [Indexed: 11/30/2022]
|
26
|
Kumagae Y, Matsui Y. Output, tissue levels, and synthesis of acetylcholine during and after transient forebrain ischemia in the rat. J Neurochem 1991; 56:1169-73. [PMID: 1900526 DOI: 10.1111/j.1471-4159.1991.tb11407.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Biochemical changes in the rat brain cholinergic system during and after 60 min of ischemia were studied using a four-vessel occlusion model. Extracellular acetylcholine (ACh) concentrations in the unanesthetized rat hippocampus markedly increased during ischemia and reached a peak (about 13.5 times baseline levels) at 5-10 min after the onset of ischemia. At 2-5 h after reperfusion, extracellular ACh concentrations were reduced to 64-72% of the levels of controls. ACh levels in the hippocampus, striatum, and cortex decreased significantly during ischemia and exceeded their control values just after reperfusion. A significant increase in hippocampal ACh level after 2 days of reperfusion and a decrease in [14C]ACh synthesis from [14C]glucose in hippocampal slices excised at 2 days after reperfusion were observed. The extracellular concentrations and tissue levels of choline markedly increased after ischemia. These results show that ACh is markedly released into the extracellular space in the hippocampus during ischemia, and they suggest that ACh synthesis is activated just after reperfusion and that cholinergic activity is reduced after 2-48 h of reperfusion in the hippocampus.
Collapse
Affiliation(s)
- Y Kumagae
- Biological Research Laboratories, Sankyo Co., Ltd., Tokyo, Japan
| | | |
Collapse
|
27
|
Pharmacological Alteration of Ultrafiltration. Nephrology (Carlton) 1991. [DOI: 10.1007/978-3-662-35158-1_166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
28
|
Williams LR, Rylett RJ. Exogenous nerve growth factor increases the activity of high-affinity choline uptake and choline acetyltransferase in brain of Fisher 344 male rats. J Neurochem 1990; 55:1042-9. [PMID: 2384747 DOI: 10.1111/j.1471-4159.1990.tb04594.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The objective of this study was to determine the effect of age and chronic intracerebral administration of nerve growth factor (NGF) on the activity of the presynaptic cholinergic neuronal markers hemicholinium-sensitive high-affinity choline uptake (HACU) and choline acetyltransferase (ChAT) in the brain of Fisher 344 male rats. In 24-month-old rats, a substantial decrease in ChAT activity (30%) was measured in striatum, and decreases in HACU were found in frontal cortex (28%) and hippocampus (23%) compared with 4-month-old controls. Cholinergic neurons in brain of both young adult and aged rats responded to administration of exogenous NGF by increased expression of both phenotypes. In 4-month-old animals, NGF treatment at 1.2 micron/day resulted in increased activities of both ChAT and HACU in striatum (175 and 170%, respectively), frontal cortex (133 and 125%), and hippocampus (137 and 125%) compared with untreated and vehicle-treated 4-month-old animals; vehicle treatment had no effect on the activity of either marker. In 24-month-old animals treated with NGF for 2 weeks, ChAT activity was increased in striatum (179%), frontal cortex (134%), and hippocampus (119%) compared with 24-month-old control animals. Synaptosomal HACU in 24-month-old rats was increased in striatum (151%) and frontal cortex (128%) after 2 weeks of NGF treatment, but hippocampal HACU was not significantly different from control values.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- L R Williams
- CNS Diseases Research, Upjohn Company, Kalamazoo, Michigan 49001
| | | |
Collapse
|
29
|
Koshimura K, Miwa S, Lee K, Hayashi Y, Hasegawa H, Hamahata K, Fujiwara M, Kimura M, Itokawa Y. Effects of choline administration on in vivo release and biosynthesis of acetylcholine in the rat striatum as studied by in vivo brain microdialysis. J Neurochem 1990; 54:533-9. [PMID: 2299351 DOI: 10.1111/j.1471-4159.1990.tb01904.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The purpose of the present study is to clarify the effects of the administration of choline on the in vivo release and biosynthesis of acetylcholine (ACh) in the brain. For this purpose, the changes in the extracellular concentration of choline and ACh in the rat striatum following intracerebroventricular administration of choline were determined using brain microdialysis. We also determined changes in the tissue content of choline and ACh. When the striatum was dialyzed with Ringer solution containing 10 microM physostigmine, ACh levels in dialysates rapidly and dose dependently increased following administration of various doses of choline and reached a maximum within 20 min. In contrast, choline levels in dialysates increased after a lag period of 20 min following the administration. When the striatum was dialyzed with physostigmine-free Ringer solution, ACh could not be detected in dialysates both before and even after choline administration. After addition of hemicholinium-3 to the perfusion fluid, the choline-induced increase in ACh levels in dialysates was abolished. Following administration of choline, the tissue content of choline and ACh increased within 20 min. These results suggest that administered choline is rapidly taken up into the intracellular compartment of the cholinergic neurons, where it enhances both the release and the biosynthesis of ACh.
Collapse
Affiliation(s)
- K Koshimura
- Department of Pharmacology, Kyoto University Faculty of Medicine, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Muramatsu M, Chaki S, Arai I, Aihara H. Alteration of metabolism of acetylcholine induced by 2-deoxy-D-glucose in the gastroduodenum of the rat. Neuropharmacology 1990; 29:47-54. [PMID: 2304615 DOI: 10.1016/0028-3908(90)90082-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
2-Deoxy-D-glucose (2-DG) administered intraperitoneally, dose-dependently increased the secretion of gastric acid, and the changes were comparable with those on the activity of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) in the stomach. Double-reciprocal plot analysis of the increased activity of CAT and AChE, induced by 2-DG, showed that the changes were due to the increase of Vmax, with no change in the Km-value for the substrates. The uptake of [3H]choline and subsequent synthesis of [3H]ACh was observed in the forestomach, corpus and antrum of the stomach and in the duodenum. 2-Deoxy-D-glucose significantly increased the uptake of [3H]choline and synthesis of [3H]ACh in every region of the stomach and in the duodenum, in a dose-dependent manner. The increase of secretion of gastric acid, induced by 2-DG paralleled that of uptake of [3H]choline and synthesis of [3H]ACh at an early stage. The conversion of [3H]choline taken up to [3H]ACh was negligibly influenced by 2-DG. Neither the content of ACh and choline, nor the turnover rate of ACh, were changed by administration of 2-DG. 2-Buten-4-olide (2-B4O), which inhibits the activity of the vagus nerve through the central nervous system, prevented 2-DG-induced uptake of [3H]choline and subsequent synthesis of [3H]ACh, as well as the increase in secretion of gastric acid. These results suggest that the uptake of [3H]choline and subsequent synthesis of [3H]ACh are closely related to the neuronal activity of the vagus nerve, and that cholinergic neuronal activity is dependent upon quantitative changes of metabolism of ACh in the gastroduodenum.
Collapse
Affiliation(s)
- M Muramatsu
- Department of Pharmacology, Taisho Pharmaceutical Co. Ltd., Ohmiya, Saitama, Japan
| | | | | | | |
Collapse
|
31
|
Bostwick JR, Landers DW, Crawford G, Lau K, Appel SH. Purification and characterization of a central cholinergic enhancing factor from rat brain: its identity as phosphoethanolamine. J Neurochem 1989; 53:448-58. [PMID: 2746232 DOI: 10.1111/j.1471-4159.1989.tb07355.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A compound that can enhance the apparent synthesis of acetylcholine in cultured explants of the medial septal nucleus has been purified from rat brain and identified as phosphoethanolamine. Acetylcholine synthesis is stimulated two- to threefold in cultures grown for 5 days in the presence of phosphoethanolamine, ethanolamine, or cytidine 5'-diphosphoethanolamine at concentrations above 100 microM. This effect appears to result from an increase in the accumulation of choline via the high-affinity, sodium-dependent uptake mechanism. The development of choline acetyltransferase activity is not affected. Phosphoethanolamine and ethanolamine seem to enhance the ability of developing cholinergic neurons to utilize choline accumulated via the sodium-dependent high-affinity choline uptake mechanism for the preferential production of acetylcholine without increasing the general metabolism of the cultures. Choline itself and its related derivatives are not stimulatory for these effects.
Collapse
Affiliation(s)
- J R Bostwick
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | | | | | | | | |
Collapse
|
32
|
Nakahara N, Iga Y, Mizobe F, Kawanishi G. Effects of intracerebroventricular injection of AF64A on learning behaviors in rats. JAPANESE JOURNAL OF PHARMACOLOGY 1988; 48:121-30. [PMID: 3199599 DOI: 10.1254/jjp.48.121] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The effects of intracerebroventricular (ICV) injection of ethylcholine aziridinium ion (AF64A) (3 nmole/2 microliter, each lateral ventricule), a putative selective cholinotoxin, on learning behaviors and choline acetyltransferase (ChAT) activity were studied in rats. AF64A-treated rats (AF64A-rat) exhibited deficient performance in a passive avoidance task and a delayed alternation task in the T-maze, but demonstrated superior avoidance response in a two-way shuttle avoidance task. These changes in learning behaviors were associated with the selective decrease of hippocampal ChAT activity. Physostigmine (0.1 mg/kg, i.p.) significantly improved the retention latency of AF64A-rats in the passive avoidance task. AF64A-rats receiving physostigmine (0.2 mg/kg, i.p.) exhibited a slight but not significant improvement of performance in the delayed alternation task in the T-maze. These findings suggested that ICV injection of AF64A may be useful for producing an experimental amnesia model with hippocampal cholinergic hypofunction like Senile dementia of the Alzheimer type (SDAT), if appropriate learning tests are selected.
Collapse
Affiliation(s)
- N Nakahara
- Research Institute of Life Science, Snow Brand Milk Products Co., Ltd., Tochigi, Japan
| | | | | | | |
Collapse
|
33
|
Russell RW. Behavioral correlates of presynaptic events in the cholinergic neurotransmitter system. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1988; 32:43-130. [PMID: 2905821 DOI: 10.1007/978-3-0348-9154-7_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
34
|
Kobayashi H, Yuyama A, Ishihara M, Matsusaka N. Effects of arsenic on cholinergic parameters in brain in vitro. Neuropharmacology 1987; 26:1707-13. [PMID: 3437937 DOI: 10.1016/0028-3908(87)90121-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effects of sodium arsenite (arsenite) on the cholinergic system in the brain of the mouse were investigated in vitro and compared with those of N-ethylmaleimide (NEM) and iodoacetate, both of which are alkylating sulfhydryl reagents. Arsenite, at concentrations greater than 10(-4) M, inhibited depolarized and nondepolarized release of acetylcholine (ACh) from cerebral slices, the synthesis of ACh in the slices, high-affinity uptake of choline into synaptosomes and activity of acetylcholinesterase (AChE). On the other hand, arsenite potentiated dose-dependently the activity of choline acetyltransferase (ChAT). N-Ethylmaleimide and iodoacetate showed inhibitory effects similar to those of arsenite. However, some exceptions were that N-ethylmaleimide did not have any effect on the nondepolarized release of ACh while iodoacetate had no effect on high affinity uptake of choline and activity of AChE. In contrast to arsenite, N-ethylmaleimide and iodoacetate inhibited the activity of ChAT. Neither of arsenite, N-ethylmaleimide nor iodoacetate showed any effect on the binding of [3H]quinuclidinyl benzilate to muscarinic ACh receptors. Although arsenite is thought to inhibit the cholinergic system in brain in vivo, its potentiating effect on ChAT and inhibition of AChE may reduce this harmful effect.
Collapse
Affiliation(s)
- H Kobayashi
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Japan
| | | | | | | |
Collapse
|
35
|
Abstract
Choline acetyltransferase (ChAT)-like immunoreactivity in the human retina can be demonstrated using a polyclonal antiserum to ChAT isolated from chick brain. There is a population of ChAT-like immunoreactive cells along both margins of the inner plexiform layer (IPL). The labeled cells have a morphology and position characteristic of the cholinergic amacrine- and displaced amacrine cells demonstrated by other workers in the mammalian retina. Non-immune rabbit serum or pre-absorbed antiserum, used in place of the primary antiserum, verified the specificity of the method. Human retinas can also be labeled with the fluorescent dye 4',6-diamidino-2-phenylindole (DAPI), which has been reported to bind selectively to DNA in the nuclei of cholinergic cells. The fluorescent cells are similar in morphology, position, and distribution to the cells which show ChAT-like immunoreactivity. In addition, we have localized the presence of [3H]choline and [3H]choline metabolites in freeze-dried, vapor-fixed tissue using 'dry' autoradiographic techniques. Incubation in [3H]choline was followed by either stimulation or inhibition of calcium-dependent transmitter release during a 1-hr 'chase' period. Using tissue incubated in a chase designed to retain labeled neurotransmitters, silver grains were concentrated over a population of cell bodies at either margin of the IPL (i.e. in the same position as putative ChAT-immunoreactive cells and DAPI-labeled cells). In contrast, tissue incubated in a chase designed to release labeled acetylcholine was labeled uniformly throughout the neural retina, with a heavy band of label over the pigment epithelium. Taken together, the results presented here indicate that three independent markers for cholinergic cells (i.e. ChAT immunoreactivity, DAPI binding, and choline uptake) are present in a population of cells in the human retina. This suggests that acetylcholine may be a neurotransmitter synthesized by amacrine and displaced amacrine cells in the retina.
Collapse
|
36
|
Banerjee U, Choudhuri D. Effect of pyrethrum on CNS and haemolymph monovalent (Na+, K+) cations and also on the level of CNS acetylcholine and activities of esterase and choline acetyltransferase in the insect Schizodactylus monstrosus drury. Neurochem Int 1987; 10:135-41. [DOI: 10.1016/0197-0186(87)90120-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/1986] [Accepted: 08/01/1986] [Indexed: 11/24/2022]
|
37
|
Wenk G, Sweeney J, Hughey D, Carson J, Olton D. Cholinergic function and memory: extensive inhibition of choline acetyltransferase fails to impair radial maze performance in rats. Pharmacol Biochem Behav 1986; 25:521-6. [PMID: 3774818 DOI: 10.1016/0091-3057(86)90134-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The present study investigated the effects of a potent inhibitor of choline acetyltransferase (ChAT), BW813U, on the choice accuracy of rats in the radial arm maze. BW813U (100 mg/kg, IP) produced a rapid (within 1 hour) and substantial decrease in ChAT activity throughout the brain, ranging from 66% (hippocampus) to 80% (caudate nucleus) that lasted up to 5 days. A single injection (50 mg/kg, IP) into rats with lesions (using ibotenic acid) in the nucleus basalis magnocellularis and medial septal area, decreased ChAT activity by 75% and 60% in the cortex and hippocampus, respectively. Lesioned and unlesioned rats were trained on the radial arm maze until they reached a criterion level of performance. Each rat then received an injection of BW813U (50 or 100 mg/kg, IP). Choice accuracy was not impaired at any time following the injection. The lack of effect on performance may be due to 2 possible factors: The radial maze retention paradigm chosen may not be sufficiently difficult, or the decrease in acetylcholine production was not sufficient to affect behavior. Compensation by non-cholinergic neural systems might account for the insensitivity of the rats to significant cholinergic depletion.
Collapse
|
38
|
Morley BJ, Garner LL. Increases in the concentration of brain alpha-bungarotoxin binding sites induced by dietary choline are age-dependent. Brain Res 1986; 378:315-9. [PMID: 3730881 DOI: 10.1016/0006-8993(86)90934-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We have previously reported that a diet supplemented with choline induces an increase in the concentration of a brain nicotinic-like receptor, as measured by alpha-bungarotoxin (BuTX) binding. Here we report the effects of choline administered in the drinking water on BuTX binding in the cortex, midbrain and brainstem of rats at 3 ages. In comparison with animals fed a choline-free diet, choline supplementation produced increases averaging 50% in 23-day-old rats and increases of approximately 30% in 60-day-old rats. Increases were also found in 6-month-old animals (averaging 16%), but the differences were generally not statistically significant. The mechanism responsible for the increase in the concentration of BuTX binding sites following the administration of dietary choline is not known, but the results are discussed in terms of choline as a precursor for the biosynthesis of acetylcholine and the biosynthesis of phospholipids. These data indicate that the administration of dietary choline is not likely to be effective in reversing cholinergic deficits by increasing the concentration of nicotinic-like receptors in aging rats.
Collapse
|
39
|
Abstract
Human retinas have the capacity to synthesize and release [3H]acetylcholine ([3H]ACh) after an incubation in [3H]choline ([3H]Ch). Synthesis of [3H]Ch by retinal homogenates was determined using either high-voltage paper electrophoresis (HVPE) or a two-step enzymatic/extraction assay for separating [3H]ACh from [3H]Ch. The enzymatic/extraction assay is shown to be accurate over a wide range of concentrations (10(-6)-10(-12) M). Homogenates of human retina synthesize [3H]ACh from [3H]Ch. We find an approximate Km of 50 microM and a Vmax of about 20 nmol/mg protein/h (at 37 degrees C) for the synthesis of labeled ACh by retinal homogenates. Human retinas also release [3H]ACh after a pulse of [3H]Ch. Release of labeled transmitter is stimulated by potassium depolarization. The potassium-stimulated release is partially blocked by magnesium or cobalt ions. Release data were analyzed by both the enzymatic/extraction assay and HVPE; the results are qualitatively identical in both cases. The data reported here provide additional evidence for cholinergic neurotransmission in the human retina.
Collapse
|
40
|
Ghag S, Wright A, Moudgil VK. Inactivation of rat brain acetylcholinesterase by pyridoxal 5'-phosphate. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 881:30-7. [PMID: 3947673 DOI: 10.1016/0304-4165(86)90093-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Effects of pyridoxal 5'-phosphate on the activity of crude and purified acetylcholinesterase from cerebral hemispheres of adult rat brain were examined. Acetylcholinesterase was completely inactivated by incubation with 0.5 mM pyridoxal 5'-phosphate. The enzyme activity remained unaltered in the presence of analogs of pyridoxal 5'-phosphate, pyridoxal, pyridoxamine and pyridoxamine 5'-phosphate. The inhibition of acetylcholinesterase activity by pyridoxal 5'-phosphate appeared to be of a noncompetitive nature, as determined by Lineweaver-Burk analysis. The inhibitory effect of pyridoxal 5'-phosphate on acetylcholinesterase appeared to be a general one, as the activity of the enzyme from the brains of immature chick and egg-laying hen, and from different tissues of the adult male rats, exhibited a similar pattern in the presence of the inhibitor. The inhibitory effects of pyridoxal 5'-phosphate could be reversed upon exhaustive dialysis of the pyridoxal 5'-phosphate-treated acetylcholinesterase preparations. We propose that the effects of pyridoxal 5'-phosphate are due to its interaction with acetylcholinesterase, and that it can be employed as a useful tool for studying biochemical aspects of this important brain enzyme.
Collapse
|
41
|
Nakahiro M, Yoshida H. The "antidementia drug" pantoyl-gamma-aminobutyric acid increases high affinity uptake of choline by slices of rat brain. Neuropharmacology 1986; 25:227-30. [PMID: 3703173 DOI: 10.1016/0028-3908(86)90244-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Studies were made on the effects of an "antidementia drug", pantoyl-gamma-aminobutyric acid (pantoyl-GABA), on high affinity uptake of choline by slices of rat brain. Depolarization caused by increasing the K+ concentration to 25 mM for 30 min before incubation with [3H]choline enhanced the uptake of radioactivity by slices of cerebral cortex, hippocampus and striatum during a 5 min incubation in the presence of 1 microM [3H]choline. Pantoyl-GABA (1 mM) increased the depolarization-induced uptake of radioactivity by the slices of cortex and hippocampus, but not by the slices of striatum; it had little effect on the uptake when the slices were not depolarized. It also had no effect when the slices were depolarized in the incubation medium without Ca2+. Since the high affinity uptake of choline is considered to be a regulatory step in the synthesis of acetylcholine (ACh), these results suggest that pantoyl-GABA increases the synthesis of ACh in cholinergic terminals in the cerebral cortex and hippocampus. This action may be involved in its effect as an antidementia drug, because cholinergic deficits are assumed to occur in Alzheimer's disease.
Collapse
|
42
|
|
43
|
Hattori H, Kanfer JN. Synaptosomal phospholipase D potential role in providing choline for acetylcholine synthesis. J Neurochem 1985; 45:1578-84. [PMID: 4045465 DOI: 10.1111/j.1471-4159.1985.tb07229.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The phospholipase D of the rat brain synaptic membrane possesses the highest activity of this enzyme of any mammalian tissue examined. The synaptic phospholipase D activity is latent and barely detectable in the absence of 4 mM sodium oleate. Several other fatty acids were either less effective or ineffective as stimulators of activity compared to this monounsaturated fatty acid. The activity was decreased by hemicholinium-3, an inhibitor of choline uptake and slightly activated by neostigmine, an acetylcholinesterase inhibitor. Incubation of synaptosomes in the presence of sodium oleate and acetyl-coenzyme A resulted in the formation of a product chromatographing with acetylcholine. Acetylcholine formation was nearly undetectable in the absence of sodium oleate or acetyl-coenzyme A. These results implicate synaptosomal phospholipase D in releasing choline from phosphatidylcholine for acetylcholine formation.
Collapse
|
44
|
Bartus RT, Dean RL, Pontecorvo MJ, Flicker C. The cholinergic hypothesis: a historical overview, current perspective, and future directions. Ann N Y Acad Sci 1985; 444:332-58. [PMID: 2990293 DOI: 10.1111/j.1749-6632.1985.tb37600.x] [Citation(s) in RCA: 244] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
45
|
Bertoni-Freddari C, Mervis RF, Giuli C, Pieri C. Chronic dietary choline modulates synaptic plasticity in the cerebellar glomeruli of aging mice. Mech Ageing Dev 1985; 30:1-9. [PMID: 3999812 DOI: 10.1016/0047-6374(85)90054-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A morphometric investigation was carried out on ethanolic phosphotungstic acid (E-PTA) stained synaptic junctions in the cerebellar glomeruli of adult, old, old choline-deficient and old choline-supplemented mice. Numerical (Nv) and surface (Sv) density as well as average length (L) of the synapses were calculated on 100 pictures per group. A significant reduction of Nv and Sv, as well as an increase of L was found during aging. Choline deficient animals did not show any change as compared to old animals of the same age. In choline supplemented mice Nv and Sv were significantly increased and L significantly decreased, respectively, as compared to old control littermates. No difference was found between adult and choline supplemented mice. In the cerebellar glomeruli only a small fraction of fibers are cholinergic, therefore the present findings support the idea that dietary choline can influence systems other than cholinergic. The possible role of choline supplementation in the modulation of synaptic plasticity via the synthesis and/or turnover of neuronal membrane choline phospholipids, is discussed.
Collapse
|
46
|
Abstract
The kinetic parameters of choline uptake into red blood cells from patients with Alzheimer's disease and normal elderly controls were compared. The Kd and Vmax values for choline uptake into red cells were determined based on a kinetic analysis of choline uptake at six different concentrations of labeled extracellular choline. The theoretical choline uptake, representing the initial rate of choline influx into choline-depleted red cells given the plasma choline concentration and the kinetic parameters of choline uptake, was also calculated. Alzheimer's disease patients and normal controls did not differ in any kinetic parameter of choline uptake. Kd and Vmax values for red cell choline uptake were strongly correlated among normal controls, but not among patients with Alzheimer's disease. In addition, among the patients with Alzheimer's disease, the theoretical choline uptake was strongly correlated with the severity of dementia. The possible significance of these findings in relation to altered choline metabolism in Alzheimer's disease is discussed.
Collapse
|
47
|
Ivy MT, Sukumar R, Townsel JG. The characterization of a sodium-dependent high affinity choline uptake system unassociated with acetylcholine biosynthesis. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1985; 81:351-7. [PMID: 2861955 DOI: 10.1016/0742-8413(85)90019-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The cardiac ganglion of the horseshoe crab, Limulus polyphemus, was incubated in Chao's solution containing 0.01 microM [3H]choline at room temperature (25 +/- 2 degrees C) and the ganglion readily accumulated the radiolabel. The ganglion uptake of [3H]choline was linear over 60 min. Kinetic analysis revealed dual choline uptake systems within the cardiac ganglion, a high affinity uptake system (Km = 2.2 microM, Vmax = 0.16 pmoles/mg/min) and a low affinity system (Km = 92.3 microM, Vmax = 3.08 pmoles/mg/min). The high affinity uptake system was sodium-dependent and inhibited by micromolar concentrations of hemicholinium-3. A 15 min pre-exposure of the ganglion to Chao's solution containing 90 mM potassium stimulated a significant increase in choline uptake. There was no detectable synthesis of [3H]acetylcholine from the [3H]choline taken up by the cardiac ganglion. The major portion of the extractable label appeared in a fraction which co-electrophoresed with phosphorylcholine. These results suggest that the sodium-dependent high affinity [3H]choline uptake system of the cardiac ganglion subserves a specific requirement for choline which is unrelated to a cholinergic function.
Collapse
|
48
|
|
49
|
Hattori H, Kanfer JN. Synaptosomal phospholipase D: potential role in providing choline for acetylcholine synthesis. Biochem Biophys Res Commun 1984; 124:945-9. [PMID: 6508788 DOI: 10.1016/0006-291x(84)91049-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The synaptic membrane (SM) prepared from rat brain synaptosomes displayed the highest activity of phospholipase D of mammalian tissue thus far observed. In common with the previously described latency of the microsomal enzyme, the SM phospholipase D (PLD) activity is barely detectable in the absence of 4 mM sodium oleate. Incubation of synaptosomes in the presence of choline labelled lecithin, sodium oleate and acetyl CoA resulted in the formation of a product co-chromatographing with acetylcholine. The potential role of SM PLD liberating choline from lecithin into the synaptic cleft is discussed in relationship to acetylcholine formation.
Collapse
|
50
|
Tuček S, Doležal V, Ričny J. Regulation of acetylcholine synthesis in presynaptic endings of cholinergic CNS neurons. NEUROPHYSIOLOGY+ 1984. [DOI: 10.1007/bf01052700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|