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Forrest TJ, Desmond TJ, Issa M, Scott PJH, Basura GJ. Evaluating Cholinergic Receptor Expression in Guinea Pig Primary Auditory and Rostral Belt Cortices After Noise Damage Using [ 3H]Scopolamine and [ 18F]Flubatine Autoradiography. Mol Imaging 2019; 18:1536012119848927. [PMID: 31099304 PMCID: PMC6537085 DOI: 10.1177/1536012119848927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Noise-induced hearing loss leads to anatomic and physiologic changes in primary auditory
cortex (A1) and the adjacent dorsal rostral belt (RB). Since acetylcholine is known to
modulate plasticity in other cortical areas, changes in A1 and RB following noise damage
may be due to changes in cholinergic receptor expression. We used
[3H]scopolamine and [18F]flubatine binding to measure muscarinic
acetylcholine receptor (mAChR) and nicotinic acetylcholine receptor (nAChR) expression,
respectively, in guinea pig A1 and RB 3 weeks following unilateral, left ear noise
exposure, and a temporary threshold shift in hearing. [3H]Scopolamine binding
decreased in right A1 and RB (contralateral to noise) compared to sham controls across all
cortical layers. [18F]Flubatine binding showed a nonsignificant upward trend in
right A1 following noise but only significantly increased in right RB and 2 layers of left
RB (ipsilateral to noise). This selective response may ultimately influence cortical
plasticity and function. The mechanism(s) by which cholinergic receptors are altered
following noise exposure remain unknown. However, these data demonstrate noise exposure
may differentially influence mAChRs that typically populate interneurons in A1 and RB more
than nAChRs that are traditionally located on thalamocortical projections and provide
motivation for cholinergic imaging in clinical patient populations of temporary or
permanent hearing loss.
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Affiliation(s)
- Taylor J Forrest
- 1 Department of Otolaryngology-Head and Neck Surgery, Kresge Hearing Research Institute University of Michigan, Ann Arbor, MI, USA.,2 Kresge Hearing Research Institute University of Michigan, Ann Arbor, MI, USA.,3 Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor MI, USA
| | - Timothy J Desmond
- 3 Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor MI, USA
| | - Mohamad Issa
- 1 Department of Otolaryngology-Head and Neck Surgery, Kresge Hearing Research Institute University of Michigan, Ann Arbor, MI, USA.,2 Kresge Hearing Research Institute University of Michigan, Ann Arbor, MI, USA
| | - Peter J H Scott
- 3 Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor MI, USA
| | - Gregory J Basura
- 1 Department of Otolaryngology-Head and Neck Surgery, Kresge Hearing Research Institute University of Michigan, Ann Arbor, MI, USA.,2 Kresge Hearing Research Institute University of Michigan, Ann Arbor, MI, USA
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Haley GE, Kroenke C, Schwartz D, Kohama SG, Urbanski HF, Raber J. Hippocampal M1 receptor function associated with spatial learning and memory in aged female rhesus macaques. AGE (DORDRECHT, NETHERLANDS) 2011; 33:309-320. [PMID: 20890730 PMCID: PMC3168603 DOI: 10.1007/s11357-010-9184-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 09/03/2010] [Indexed: 05/29/2023]
Abstract
Of the acetylcholine muscarinic receptors, the type 1 (M1) and type 2 (M2) receptors are expressed at the highest levels in the prefrontal cortex (PFC) and hippocampus, brain regions important for cognition. As equivocal findings of age-related changes of M1 and M2 in the nonhuman primate brain have been reported, we first assessed age-related changes in M1 and M2 in the PFC and hippocampus using saturation binding assays. Maximum M1 receptor binding, but not affinity of M1 receptor binding, decreased with age. In contrast, the affinity of M2 receptor binding, but not maximum M2 receptor binding, increased with age. To determine if in the elderly cognitive performance is associated with M1 or M2 function, we assessed muscarinic function in elderly female rhesus macaques in vivo using a scopolamine challenge pharmacological magnetic resonance imaging and in vitro using saturation binding assays. Based on their performance in a spatial maze, the animals were classified as good spatial performers (GSP) or poor spatial performers (PSP). In the hippocampus, but not PFC, the GSP group showed a greater change in T(2)*-weighted signal intensity after scopolamine challenge than the PSP group. The maximum M1 receptor binding and receptor binding affinity was greater in the GSP than the PSP group, but no group difference was found in M2 receptor binding. Parameters of circadian activity positively correlated with the difference in T(2)*-weighted signal intensity before and after the challenge, the maximum M1 receptor binding, and the M1 receptor binding affinity. Thus, while in rhesus macaques, there are age-related decreases in M1 and M2 receptor binding, in aged females, hippocampal M1, but not M2, receptor function is associated with spatial learning and memory and circadian activity.
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Affiliation(s)
- Gwendolen E. Haley
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Chris Kroenke
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Daniel Schwartz
- Portland Veterans Administration Medical Center, Division of Psychiatry, Oregon Health and Science University, Portland, OR 97239 USA
| | - Steven G. Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
| | - Henryk F. Urbanski
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Jacob Raber
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
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Kilbourn M, Sherman P. In vivo binding of (+)-alpha-[3H]dihydrotetrabenazine to the vesicular monoamine transporter of rat brain: bolus vs. equilibrium studies. Eur J Pharmacol 1997; 331:161-8. [PMID: 9274975 DOI: 10.1016/s0014-2999(97)01054-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The regional rat brain distribution of (+)-alpha-[3H]dihydrotetrabenazine was determined following (a) infusion to equilibrium between brain and blood or (b) bolus injection. Infusions provide for direct measurement of total distribution volumes. The free plus nonspecific distribution volume for the brain was determined using infusion of very low specific activity (+)-alpha-[3H]dihydrotetrabenazine; specific distribution volumes, which represent specific radioligand binding, were then calculated as total minus the free + nonspecific distribution volume. Both total and specific distribution volumes correlated very well (r2 > 0.99) with in vitro distributions of the vesicular monoamine transporter binding site. Bolus injection, and measurement of radioactivity at a single time point, also provided regional estimates of radioligand binding which correlated well (r2 > 0.98) with in vitro values. The bolus method shows a small positive bias (+ 10-15%) in regions of high binding site concentrations. Both infusion and bolus injection methods give acceptable in vivo measures of (+)-alpha-[3H]dihydrotetrabenazine binding to the vesicular monoamine transporter of rat brain.
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Affiliation(s)
- M Kilbourn
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109, USA.
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Kilbourn MR, Snyder SE, Sherman PS, Kuhl DE. In vivo studies of acetylcholinesterase activity using a labeled substrate, N-[11C]methylpiperdin-4-yl propionate ([11C]PMP). Synapse 1996; 22:123-31. [PMID: 8787128 DOI: 10.1002/(sici)1098-2396(199602)22:2<123::aid-syn5>3.0.co;2-f] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Two esters, N-[11C]methylpiperidyl acetate ([11C]AMP) and N-[11C]methylpiperidyl propionate ([11C]PMP), were synthesized in no-carrier-added forms and evaluated as in vivo substrates for brain acetylcholinesterase (AChE). After peripheral injection in mice, each ester showed rapid penetration into the brain and a regional retention of radioactivity (striatum > cortex, hippocampus > cerebellum) reflecting known levels of AChE activity in the brain. Regional brain distributions after [11C]PMP administration showed better discrimination between regions of high, intermediate, and low AChE activities. Chromatographic analysis of blood and brain tissue extracts showed rapid and nearly complete hydrolysis of [11C]PMP within 10 min after injection. For both [11C]AMP and [11C]PMP, retention of radioactivity in all regions was reduced by pretreatment with diisopropylfluorophosphate (DFP), a specific irreversible AChE inhibitor. DFP treatment also significantly increased the proportions of unhydrolyzed ester in both blood and brain. Radioactivity localization in brain after peripheral injection was thus dependent on AChE-catalyzed hydrolysis to the hydrophilic product N-[11C]methylpiperidinol. PET imaging of [11C]AMP or [11C]PMP distributions in monkey brain showed clear accumulation of radioactivity in areas of highest AChE activity (striatum, cortex). These esters are thus in vivo substrates for brain AChE, with potential applications as in vivo imaging agents of enzyme action in the human brain. [11C]PMP, the ester with a slower rate of hydrolysis, appears to be the better candidate radiotracer for further development.
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Affiliation(s)
- M R Kilbourn
- Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor 48109, USA
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Sunderland T, Esposito G, Molchan SE, Coppola R, Jones DW, Gorey J, Little JT, Bahro M, Weinberger DR. Differential cholinergic regulation in Alzheimer's patients compared to controls following chronic blockade with scopolamine: a SPECT study. Psychopharmacology (Berl) 1995; 121:231-41. [PMID: 8545529 DOI: 10.1007/bf02245634] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of low-dose chronic scopolamine on measures of cerebral perfusion and muscarinic receptors were tested in eight Alzheimer's disease (AD) subjects and eight elderly controls. Single photon emission computed tomography (SPECT) scans using technetium-labelled hexamethypropylene amine oxide (99mTc-HMPAO) to measure cerebral perfusion before and after chronic scopolamine revealed a significant 12% increase in the normal controls (P < 0.01) while the AD subjects showed no significant change. In contrast, the controls showed decreased muscarinic binding as evidenced by 123I-quinuclidinyl-4-iodobenzilate (123I-QNB) labelling after chronic drug (-10%, P < 0.01) whereas the AD subjects showed increased 123I-QNB labelling (+8%, P < 0.05). The difference between AD and control subjects was even more marked when the ratio of I-QNB to HMPAO uptake was compared, pointing to a double dissociation in the SPECT results. These data cannot be explained by group differences in cerebral perfusion alone and suggest a differential sensitivity between AD and elderly controls to chronic cholinergic blockade.
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Affiliation(s)
- T Sunderland
- Section on Geriatric Psychiatry, LCS, National Institute of Mental Health, Bethesda, MD 20892, USA
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Mulholland GK, Kilbourn MR, Sherman P, Carey JE, Frey KA, Koeppe RA, Kuhl DE. Synthesis, in vivo biodistribution and dosimetry of [11C]N-methylpiperidyl benzilate ([11C]NMPB), a muscarinic acetylcholine receptor antagonist. Nucl Med Biol 1995; 22:13-7. [PMID: 7735163 DOI: 10.1016/0969-8051(94)00082-u] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
4-N-Methylpiperidyl benzilate (NMPB), a high affinity antagonist for the muscarinic cholinergic receptor, has been synthesized in carbon-11-labeled form through the N-[11C]methylation of 4-piperidylbenzilate. The product was isolated by HPLC, and obtained in yields (> 100 mCi) and specific activities (500-3000 Ci/mmol) sufficient for in vivo evaluation in small animals. Time-dependent regional brain distributions in rats and mice showed high radiotracer uptake and retention in striatum and cortex, and low in cerebellum, consistent with muscarinic cholinergic receptor distributions. Radiotracer retention in tissues could be significantly reduced by pretreatment of animals with a large dose of a competing antagonist, quiniclidinyl benzilate. Whole body biodistribution in rats was used to calculate the expected human internal radiation dosimetry for this new radiopharmaceutical. These animal experiments formed the basis for subsequent introduction of [11C]NMPB into human use with positron emission tomography.
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Affiliation(s)
- G K Mulholland
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109, USA
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Müller-Gärtner HW, Mayberg HS, Fisher RS, Lesser RP, Wilson AA, Ravert HT, Dannals RF, Wagner HN, Uematsu S, Frost JJ. Decreased hippocampal muscarinic cholinergic receptor binding measured by 123I-iododexetimide and single-photon emission computed tomography in epilepsy. Ann Neurol 1993; 34:235-8. [PMID: 8338348 DOI: 10.1002/ana.410340221] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Regional binding of 123I-iododexetimide, a muscarinic acetylcholine receptor antagonist, was measured in vivo in the temporal lobes of 4 patients with complex partial seizures using single-photon emission computed tomography. In the anterior hippocampus ipsilateral to the electrical focus, 123I-iododexetimide binding was decreased by 40 +/- 9% (mean +/- SD, p < 0.01) compared with the contralateral hippocampus; 123I-iododexetimide binding in other temporal lobe regions was symmetrical. The data indicate a regionally specific change of muscarinic acetylcholine receptor in anterior hippocampus in complex partial seizures of temporal lobe origin.
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Affiliation(s)
- H W Müller-Gärtner
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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