Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Male Fischer-344 rats aged 6, 12, or 24 months were subjected to four-vessel occlusion cerebral ischemia to assess age-dependent ischemic vulnerability of cholinergic and GABAergic neurons based on choline acetyltransferase (EC 2.3.1.6) and glutamic acid decarboxylase (EC 4.1.1.15) activities. Activities of both enzymes were similar (p greater than 0.05) in 6- (n = 5) and 12- (n = 5) month-old rats. Mean +/- SEM choline acetyltransferase activities in the cortex, hippocampus, striatum, and cerebellum of 6-month-old controls were 75 +/- 5, 123 +/- 9, 415 +/- 9, and 50 +/- 4 nmol acetylcholine/hr/mg protein, respectively, and were 20-30% lower (p less than 0.05) in all brain regions except the cerebellum in 24-month-old controls. Choline acetyltransferase activity was unaffected by ischemia in 6- and 12-month-old rats but was reduced by 30-60% in 24-month-old rats. Mean +/- SEM glutamic acid decarboxylase activities in the cortex, hippocampus, striatum, and cerebellum of 6-month-old controls were 98 +/- 8, 86 +/- 7, 144 +/- 13, and 125 +/- 9 nmol gamma-aminobutyric acid/hr/mg protein, respectively, and 25-35% lower in all regions of 24-month-old controls. After 30 minutes of ischemia and 5 days of recovery, glutamic acid decarboxylase activities were reduced (p less than 0.05) in all brain regions and age groups. However, its activity was decreased (p less than 0.05 compared with age-matched controls) by 55% in the cortex and 79% in the hippocampus of 24-month-old rats compared with 30% and 45% in younger rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Stroke 1989 Apr
PMID:Age-dependent vulnerability of brain choline acetyltransferase activity to transient cerebral ischemia in rats. 292 26

The presence and distribution of a cerebrovascular cholinergic system were studied in goats. Regional cerebral blood flow was measured in the parietal cerebral cortex, caudate nucleus, and white matter by the hydrogen clearance technique in unanesthetized goats. Intravenous low doses of physostigmine, but not of neostigmine, significantly increased regional blood flow without changing mean arterial blood pressure or behavior. Increases of blood flow were greater in cerebral cortex and caudate nucleus than in white matter although the vasodilation induced by hypercapnia was similar in the three regions. Intracerebral microvessels were isolated from cerebral cortex, caudate nucleus, and white matter to evaluate choline acetyltransferase activity as a marker for perivascular cholinergic nerves. The enzyme level was higher in vessels from cerebral cortex and caudate nucleus than in vessels from white matter, which is in accordance with the functional data. These results suggest the presence of a cholinergic perivascular innervation system in intracerebral microvessels. Such innervation has a nonhomogeneous distribution throughout the brain and might be implicated in the local regulation of cerebral blood flow.
Stroke 1988 Jun
PMID:Regional differences in cerebrovascular cholinergic innervation in goats. 337 65

Various concentrations of acetylcholine (ACh) produced dose dependent relaxations of isolated, helical preparations of human cerebral arteries and these responses were blocked by atropine. The median effective concentration (EC50) of ACh was 6.1 +/- 0.2 X 10(-6)M. ACh produced dual responses in isolated dog cerebral arteries. ACh in low concentrations produced relaxation, and contraction occurred when the concentration was raised to 1 X 10(-5)M. The EC50 of ACh which produced relaxation, in dog cerebral arteries was 7.2 +/- 0.2 X 10(-7)M. Muscarinic cholinergic receptors in these arteries were analyzed directly using 3H-QNB as the ligand. The specific 3H-QNB binding to the arteries was saturable and of KD = 1.5 nM and Bmax = 93 fmol/mg protein in human cerebral arteries and KD = 0.59 nM, Bmax = 340 fmol/mg protein in dog cerebral arteries. Specific binding of 3H-QNB was displaced by muscarinic cholinergic agents. Ki values and Hill coefficients were as follows: QNB, 1.0 X 10(-9)M, 0.89; atropine, 1.1 X 10(-8)M, 0.95; ACh, 0.8 X 10(-8)M and 2.1 X 10(-6)M, 0.54; carbachol, 1.2 X 10(-7)M and 4.3 X 10(-5)M, 0.33 in human cerebral arteries and QNB, 0.55 X 10(-9)M, 0.85; atropine 0.9 X 10(-9)M, 1.00; ACh, 0.9 X 10(-9)M and 1.1 X 10(-6)M, 0.43; carbachol 6.3 X 10(-8)M and 1.1 X 10(-5)M, 0.36 in dog cerebral arteries. Endogenous choline acetyltransferase (ChAT) activity was 1.6 +/- 0.4 nmol/mg protein/hr in human cerebral arteries and 3.7 +/- 0.1 nmol/mg protein/hr in dog cerebral arteries.(ABSTRACT TRUNCATED AT 250 WORDS)
Stroke
PMID:Characterization of muscarinic cholinergic receptors in human and dog cerebral arteries. 396 40

To study the role of central cholinergic mechanisms in hypertension, we have determined muscarinic receptors using [3H] (-)quinuclidinyl benzilate (QNB) and choline acetyltransferase (ChAT) activity in the brain regions of spontaneously hypertensive rats (SHR), stroke-prone SHR (SHRSP) and renal hypertensive rats. The number of muscarinic receptors was significantly (33-38 %) elevated in the hypothalamus of SHR and SHRSP at the ages of 16 and 24 weeks compared to that of Wistar-Kyoto rats (WKY). An increased density of muscarinic receptors was consistently observed in the prehypertensive (5 weeks) and developmental (10 weeks) stages of hypertension. In contrast, in the hypothalamus of rats with renal hypertension there was no muscarinic receptor alteration. The receptor alteration in the SHRSP hypothalamus was not abolished by a chronic hypotensive treatment which prevented the development of hypertension, suggesting that an enhancement of the muscarinic receptors in spontaneous hypertension does not occur secondarily to the elevation of blood pressure. The hypothalamus of SHR and SHRSP at the ages of 5 and 24 weeks showed significantly less activity of ChAT. These data demonstrate that there is a specific increase in muscarinic receptors and a decrease in cholinergic activity in the hypothalamus of SHR and SHRSP. Thus, the present study suggests an important role for hypothalamic cholinergic receptors in the pathogenesis of spontaneous hypertension.
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PMID:Muscarinic cholinoceptors and choline acetyltransferase activity in the hypothalamus of spontaneously hypertensive rats. 672 55

Post-mortem determinations of muscarinic cholinergic receptor parameters by means of binding procedures were carried out in human brains. In patients who died from internal capsule stroke a significant increase in cortical (Brodmann area 8) muscarinic receptor density was present when compared to non-neurological controls. No significant changes were detected in cortical choline acetyltransferase. Subcortical structures such as thalamus and caudate nucleus seemed to undergo opposite effects. It is suggested that acute interruption of fibers ascending to the cortex from subcortical areas can alter muscarinic receptor properties in the cerebral cortex.
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PMID:Acute subcortical lesions modify cortical muscarinic receptors in human brain. 716 4

Alzheimer's disease accounts for approximately two thirds of all cases of dementia in the United States and $90 billion in health care costs annually. Clinical and laboratory diagnostic tools have been refined so that clinicians now can diagnose Alzheimer's disease with up to 90% accuracy. Criteria for clinical diagnosis have been outlined by a work group of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association. Key diagnostic tools include a complete patient history, mental status testing, and a thorough diagnostic workup to exclude the possibility of a reversible disease mimicking the symptoms of Alzheimer's disease. Currently, management of Alzheimer's disease involves a two-pronged approach: behavioral-supportive care and pharmacologic control of disruptive behavioral symptoms. In the future, drug therapy may be available to maintain memory and cognitive function. Cholinesterase inhibitors, which block the decrease in choline acetyltransferase activity associated with Alzheimer's disease, appear promising. The realistic goal of health care providers at the present time, however, should be symptom control rather than disease reversal.
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PMID:Advances in Alzheimer's disease. A review for the family physician. 817 55

Stroke prone spontaneously hypertensive rats (SHRSP) were less susceptible to stress in gastric lesions than Wistar-Kyoto rats used as normotensive controls. The gastric lesions induced by water-immersion restraint (WIR) in SHRSP were aggravated by pretreatment with 6-hydroxydopamine (6-OHDA), an agent for chemical sympathectomy, following decreases in blood pressure and sympathetic nerve function. 6-OHDA treatment remarkably reduced norepinephrine content but caused increases in dopamine content and in choline acetyltransferase activity in the stomach. The mechanism of aggravation of gastric lesions in SHRSP was investigated with regard to gastric acid and motility. The pretreatment with 6-OHDA of SHRSP significantly increased the acid secretion stimulated by 2-deoxy-D-glucose indirectly acting on parietal cells via the vagus nerve, but did not change the acid secretions stimulated by carbachol, pentagastrin and histamine acting directly on parietal cells. Gastric (corpus) motility associated with WIR was completely blocked by atropine. The pretreatment with 6-OHDA in SHRSP decreased the gastric motility during WIR, which was facilitated by treatment with domperidone. These results indicate that the sympathetic hyperactivity of the stomach prevents WIR-induced gastric lesion formation mainly via the inhibition of gastric acid secretion.
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PMID:The role of sympathetic neurons for low susceptibility to stress in gastric lesions. 832 Oct 86

A 53-year-old Japanese woman with a point mutation in mitochondrial DNA (tRNALeu(UUR), nt3243) consistent with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and Alzheimer-type brain pathology is reported. This woman had suffered myopathy and psychosis without any clinical evidence of, stroke-like episodes during the last 10 years of her life, and had died after an accident. At autopsy 30 h post mortem, a part of the brain was snap frozen for biochemical and histochemical studies, and the remaining part was processed for a routine examination and electron microscopy. In the brain there were no ischemic lesions. Instead, primitive/diffuse senile plaques were found throughout the brain, predominantly in the frontal and temporal lobes, while Alzheimer neurofibrillary tangles were found only in the parahippocampal gyrus. These plaques were positive for beta-protein and mostly negative for tau protein, ubiquitin, neurofilaments, alpha-choline acetyltransferase, and acetylcholinesterase. Mutations in codon 331 of the ND2 gene as well as codons 693, 713 and 717 of the beta-amyloid precursor protein gene, known to be responsible for some cases of familial Alzheimer disease, were not found. Furthermore, coincidental Down syndrome was ruled out by chromosome analysis. The results suggest a possible correlation between this mitochondrial DNA abnormality and Alzheimer-type pathology.
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PMID:Alzheimer-type pathology in a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). 887 Aug 35

The cellular mechanisms underlying the neuroprotective action of the immunosuppressant FK506 in experimental stroke remain uncertain, although in vitro studies have implicated an antiexcitotoxic action involving nitric oxide and calcineurin. The present in vivo study demonstrates that intraperitoneal pretreatment with 1 and 10 mg/kg FK506, doses that reduced the volume of ischemic cortical damage by 56-58%, did not decrease excitotoxic damage induced by quinolinate, NMDA, and AMPA. Similarly, intravenous FK506 did not reduce the volume of striatal quinolinate lesions at a dose (1 mg/kg) that decreased ischemic cortical damage by 63%. The temporal window for FK506 neuroprotection was defined in studies demonstrating efficacy using intravenous administration at 120 min, but not 180 min, after middle cerebral artery occlusion. The noncompetitive NMDA receptor antagonist MK801 reduced both ischemic and excitotoxic damage. Histopathological data concerning striatal quinolinate lesions were replicated in neurochemical experiments. MK801, but not FK506, attenuated the loss of glutamate decarboxylase and choline acetyltransferase activity induced by intrastriatal injection of quinolinate. The contrasting efficacy of FK506 in ischemic and excitotoxic lesion models cannot be explained by drug pharmacokinetics, because brain FK506 content rose rapidly using both treatment protocols and was sustained at a neuroprotective level for 3 d. Although these data indicate that an antiexcitotoxic mechanism is unlikely to mediate the neuroprotective action of FK506 in focal cerebral ischemia, the finding that intravenous cyclosporin A (20 mg/kg) reduced ischemic cortical damage is consistent with the proposed role of calcineurin.
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PMID:Neuroprotective actions of FK506 in experimental stroke: in vivo evidence against an antiexcitotoxic mechanism. 927 29

The aim of the study was to further investigate the effects of aniracetam, a cognition enhancer, and its metabolites on the brain cholinergic system. We measured choline acetyltransferase activity and acetylcholine release using in vivo brain microdialysis in stroke-prone spontaneously hypertensive rats (SHRSP). The enzyme activity in the pons-midbrain and hippocampus, and basal acetylcholine release in the nucleus reticularis thalami were lower in SHRSP than in age-matched Wistar Kyoto rats, indicating central cholinergic deficits in SHRSP. Repeated treatment of aniracetam (50 mg/kg p.o. x 11 for 6 days) preferentially increased the enzyme activity in the thalamus, whereas decreased it in the striatum. Among the metabolites of aniracetam, local perfusion of N-anisoyl-gamma-aminobutyric acid (GABA, 0.1 and/or 1 microM) and p-anisic acid (1 microM) into the nucleus reticularis thalami, dorsal hippocampus and prefrontal cortex of SHRSP produced a significant but delayed increase of acetylcholine release. We failed, however, to find any effect of aniracetam itself. A direct injection of N-anisoyl-GABA (1 nmol) into the pedunculopontine tegmental nucleus of SHRSP enhanced the release in the nucleus reticularis thalami. Thus, these data prove that aniracetam can facilitate central cholinergic neurotransmission via both metabolites. Based on its pharmacokinetic profile, N-anisoyl-GABA may contribute to the clinical effects of aniracetam, mainly by acting on the reticulothalamic cholinergic pathway.
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PMID:Activation of the reticulothalamic cholinergic pathway by the major metabolites of aniracetam. 1051 66


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