title: Alterations in the cholinergic system after frontal cortical infarction in rat brain: pharmacological magnetic resonance imaging of muscarinic receptor responsiveness and stereological analysis of cholinergic forebrain neurons.
abstract: Vascular cognitive impairment has been related to dysfunction of the central cholinergic system. Studies exploring the putative relationship between vascular cognitive impairment and cholinergic dysfunction have largely been aimed at symptomatic cholinergic treatment rather than focusing on etiological and pathological factors. The present study characterizes chronic responses of the cholinergic system to focal cerebral infarction. Two separate experiments investigated changes in receptor responsiveness versus changes in cell number after photothrombotic infarction of the frontal cortex in rat brain. First, we conducted pharmacological magnetic resonance imaging (phMRI) together with pilocarpine injection to assess relative cerebral blood volume (CBV) responses related to cholinergic muscarinic receptor activation. PhMRI was conducted at 1 and 3 weeks after photothrombotic infarction of either the left or right frontal cortex. Second, stereological assessment was performed on choline acetyltransferase (ChAT)-immunostained sections to determine cholinergic cell body count in several basal forebrain nuclei at 4 weeks after infarction. Significant reductions in relative CBV responses were observed both inside the ischemic area at 1 and 3 weeks, and in areas distant from the lesion at 3 weeks after right-sided frontal cortical infarction. In contrast, cholinergic cell number remained unchanged. These results demonstrate that cholinergic receptor responsiveness may be significantly altered following cerebral infarction, while projecting cholinergic cells are preserved.
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Oxfordlaan 10, PO Box 5800, 6202 AZ Maastricht, The Netherlands. e.hoff@atriummc.nl
authors.forename: Erik I
authors.initials: EI
authors.lastname: Hoff
authors.forename: Harry W M
authors.initials: HW
authors.lastname: Steinbusch
authors.forename: Robert J
authors.initials: RJ
authors.lastname: van Oostenbrugge
authors.forename: Lillian
authors.initials: L
authors.lastname: Garrett
authors.forename: Willem M
authors.initials: WM
authors.lastname: Otte
authors.forename: Kajo
authors.initials: K
authors.lastname: van der Marel
authors.forename: Rick M
authors.initials: RM
authors.lastname: Dijkhuizen
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D002452:Cell Count / Q000379:methods; D002544:Cerebral Infarction / Q000378:metabolism / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005625:Frontal Lobe / Q000378:metabolism / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D009474:Neurons / Q000473:pathology* / Q000502:physiology; D010862:Pilocarpine / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D011976:Receptors, Muscarinic / Q000378:metabolism* / Q000502:physiology; D020521:Stroke / Q000378:metabolism / Q000473:pathology
chemical_list: D018721:Muscarinic Agonists; D011976:Receptors, Muscarinic; D010862:Pilocarpine; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine