Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the review article, the results of studies on regional cerebral blood flow (rCBF) in major depression are presented. Most studies have reported global and regional deficits in cerebral blood flow in major depression as compared to healthy controls. Longitudinal studies show that after recovery from depression an increase of CBF has been observed. The influence of different biological treatment methods on rCBF is also discussed. Findings regarding lateral asymmetries of cerebral function in patients with major depression are inconclusive but the deficit of rCBF is often more pronounced in the left hemisphere. The nature of regional brain flow abnormalities in depression is unclear. Structural changes of the brain and biochemical abnormalities are under consideration.
 ...
PMID:[Regional cerebral blood flow in depression]. 1078 50

We investigated the contribution of ATP-sensitive potassium channels (K(ATP)) and calcium-activated potassium channels (Kca2+) to cortical spreading depression (CSD)-associated hyperemia using the rat closed cranial window model. The peak CBF response was enhanced by 12 +/- 5, 13 +/- 4, and 28 +/- 8% (p<0.01) of the control with 10(-6), 10(-5) and 10(-4) mol/l glibenclamide (glyb), a K(ATP) antagonist, respectively. We also calculated the area under the CBF curve to fully represent the extent of hyperemia during CSD. The area increased by 30 +/- 8 (p<0.05), 72 +/- 31 (p<0.05) and 88 +/- 20% (p<0.05) of the control with 10(-6), 10(-5) and 10(-4) mol/l glyb, respectively. However, charybdotoxin (CTX), a Kca2+ antagonist showed no effect. The effect of glyb was inhibited by pretreatment with 5 mg/kg indomethacin. We conclude that activation of K(ATP), perhaps associated with neurons, plays an inhibitory role in the CSD-associated hyperemia via an indomethacin-sensitive mechanism.
 ...
PMID:Glibenclamide enhances cortical spreading depression-associated hyperemia in the rat. 1092 52

To elucidate the changes in the mitochondrial redox state during spreading depression (SD), tissue NADH content was measured in 20 anesthetized gerbils by the enzymatic cycling assay in a small cortical region (0.30+/-0.07 mg) where the direct-current (DC)-potential was measured. Sequential imaging of NADH fluorescence with a CCD camera and continuous monitoring of DC-potential and regional CBF were also performed in another 5 gerbils. Biphasic fluorescence waves propagating at the rate of 3 mm/min were observed using the CCD camera. An initial narrow (1.6+/-0.4 mm) wave, which showed a modest increase in fluorescence (108+/-6.4%), was observed simultaneously with the onset of negative DC-deflection. During depolarization, CBF was unchanged and tissue NADH content increased to 25.3+/-7.9 micromol/kg brain, which was higher than the value in the sham-control (11.0+/-2.5 micromol/kg brain). At 30 s after the deflection, a subsequent wide (7.0+/-2.1 mm) wave, which showed a moderate decrease in fluorescence (87.1+/-5.7%), was observed simultaneously with the increase in CBF and repolarization in DC-potential. Then NADH fluorescence recovered along with normalization of CBF at 152.2+/-38.6 s after the onset of DC-deflection. Tissue NADH concentration sampled at 120 s after the deflection was 11.6+/-4.6 micromol/kg brain. Since NADH fluorescence is absorbed by hemoglobin, the initial increase and subsequent decrease in fluorescence seem to have been induced by increases in NADH content and CBF, respectively. These findings indicate that the mitochondrial redox state transiently inclines to the reduction side synchronous to the onset of DC-deflection and that it normalizes within 120 s after deflection.
 ...
PMID:Dynamic changes of NADH fluorescence images and NADH content during spreading depression in the cerebral cortex of gerbils. 1092 11

To clarify the effects of spreading depression (SD) on cerebral circulation and metabolism, we elicited a single or repetitive episode of SD and evaluated CBF and CMRglc three-dimensionally in normal cats (n=4, in each group) using a high-resolution positron emission tomography (PET) scanner. SD was evoked by applying KCl to the left occipital cortex. We then monitored DC potential changes with tungsten electrodes inserted into the left temporal cortex. CBF was measured twice before and three times (immediately, 30-60 min, and 60-120 min) following KCl application using [15O]H(2)O, and CMRglc was determined using 2-[18F]fluoro-2-deoxy-D-glucose immediately following the last CBF measurement. The following results were obtained: (1) a single episode of SD produced a temporary CBF increase, followed by a long-lasting hypoperfusion in the cortex, with no significant changes to CBF observed in the subcortex; (2) no significant CMRglc changes were observed in either cortical or subcortical regions following a single episode of SD; (3) a flow-metabolism uncoupling was observed in the cortical regions concurrently with persistent hypoperfusion; (4) repetitive SD produced significant CBF changes in the cortex; and (5) the cortical CMRglc increased as a result of repeated episodes of SD, with no significant changes observed in the subcortex. Thus, we succeeded in determining three-dimensionally the effects of single and repetitive SD on CBF and CMRglc in cats using a high-resolution PET scanner. The present study provides the first direct evidence of CBF-CMRglc uncoupling occurring concurrently with persistent hypoperfusion following SD.
 ...
PMID:Effects of single and repetitive spreading depression on cerebral blood flow and glucose metabolism in cats: a PET study. 1093 May 93

The effect of cortical spreading depression (CSD) on oxygen demand (extracellular K(+)), oxygen supply (cerebral blood flow - CBF) and oxygen balance (mitochondrial NADH) was studied by a special multiprobe assembly (MPA), during hypoxia and partial ischemia. The MPA was constructed and applied to monitor the CSD wave from its front line until complete recovery, continuously and simultaneously. CSD under hypoxia or partial ischemia led to an initial increase in NADH levels and a further decrease in CBF during the first phase of the CSD wave, indicating a decrease of tissue capability to compensate for an increase in oxygen demand. Furthermore, the special design of the MPA enabled identifying the close interrelation between oxygen demand, supply and balance during CSD propagation. In conclusion, brain oxygenation was shown to have a clear effect on tissue responses to CSD.
 ...
PMID:Effects of brain oxygenation on metabolic, hemodynamic, ionic and electrical responses to spreading depression in the rat. 1105 2

The purpose of this study was to determine changes in regional cerebral blood flow (rCBF) associated with premenstrual syndrome (PMS). Regional CBF was examined using single photon emission computed tomography (SPECT) in seven women who sought treatment for PMS and seven control subjects. Confirmation of PMS was based on the Daily Symptom Report (DSR) of 17 common symptoms associated with PMS. A first SPECT scan was performed near the peak of premenstrual symptoms based on DSR reports from the two previous cycles. A second scan was performed in the postmenstrual period. Prior to scanning, each subject had a Hamilton Depression Rating Scale (Ham-D) obtained. Regions of interest were drawn on the images to generate mean counts per pixel, and normalized to the cerebellum. Activity in the frontal, temporal and parieto-occipital cortices, and the thalami and basal ganglia, were compared between the two scans. Correlations between activity in each region of interest and Ham-D values were also determined. There were marked decreases in rCBF in the temporal lobes on the premenstrual scan compared to the postmenstrual scan in PMS patients. Significant correlations were observed between the change in rCBF in the right and left temporal lobes and the changes in Ham-D scores (r = 0.91, p < 0.01 and r = 0.86, p = 0.01 respectively). No rCBF changes were observed in controls. We conclude that SPECT imaging demonstrates modest decreases in rCBF in the temporal lobes that correlate with the level of depression in subjects with PMS.
 ...
PMID:Changes in cerebral blood flow associated with premenstrual syndrome: a preliminary study. 1107 37

Positron emission tomography was used to evaluate 3 Alzheimer's disease (AD) patients: 1 with major depression, 1 with emotional lability, and 1 with apathy. Compared with 5 non-mood-disordered AD patients, the patient with depression had diminished relative regional cerebral blood flow (rel-CBF) in the anterior cingulate and superior temporal cortices, bilaterally. This patient also showed diminished rel-CBF in the left dorsolateral prefrontal and right medial temporal and parietal cortices. The patient with emotional lability had diminished rel-CBF in the anterior cingulate and dorsolateral prefrontal cortices, bilaterally, and left basal ganglia. The patient with apathy had diminished rel-CBF in the basal ganglia and dorsolateral prefrontal cortex, bilaterally. Results are consistent with the hypothesis of a common frontal-temporal-subcortical substrate (e.g., involving aminergic nuclei) in the etiology of depression in AD. Frontal-subcortical dysfunction may also be associated with emotional lability and apathy in AD, although these may be related to a greater involvement of frontal-basal ganglia circuits.
 ...
PMID:Psychiatric symptoms associated with cortical-subcortical dysfunction in Alzheimer's disease. 1120 30

The renal medulla is sensitive to hypoxia, and a depression of medullary circulation, e.g. in response to angiotensin II (Ang II), could endanger the function of this zone. Earlier data on Ang II effects on medullary vasculature were contradictory. The effects of Ang II on total renal blood flow (RBF), and cortical and medullary blood flow (CBF and MBF: by laser-Doppler flux) were studied in anaesthetised rats. Ang II infusion (30 ng kg(-1) min(-1) i.v.) decreased RBF 27 +/- 2 % (mean +/- S.E.M.), whereas MBF increased 12 +/- 2 % (both P < 0.001). Non-selective blockade of Ang II receptors with saralasin (3 microg kg(-1) min(-1) i.v.) increased RBF 12 +/- 2 % and decreased MBF 8 +/- 2 % (P < 0.001). Blockade of AT(1) receptors with losartan (10 mg kg(-1)) increased CBF 10 +/- 2 % (P < 0.002) and did not change MBF. Losartan given during Ang II infusion significantly increased RBF (53 +/- 7 %) and decreased MBF (27 +/- 7 %). Blockade of AT(2) receptors with PD 123319 (50 microg kg(-1) min(-1) i.v.) did not change CBF or MBF. Intramedullary infusion of PD 123319 (10 microg min(-1)) superimposed on intravenous Ang II infusion did not change RBF, but slightly decreased MBF (4 +/- 2 %, P < 0.05). We conclude that in anaesthetised surgically prepared rats, exogenous or endogenous Ang II may not depress medullary circulation. In contrast to the usual vasoconstriction in the cortex, vasodilatation was observed, possibly related to secondary activation of vasodilator paracrine agents rather than to a direct action via AT(2) receptors.
 ...
PMID:Differential effect of angiotensin II on blood circulation in the renal medulla and cortex of anaesthetised rats. 1177 24

In acute brain disorders, elimination of the excitatory output from an injured brain region reduces activity in connecting brain regions remote from the lesion site (i.e., diaschisis). The authors examined the effect of functional ablation of the left cerebral cortex by cortical spreading depression (CSD) or topical application of tetrodotoxin on single cell spiking activity, baseline CBF, and neurovascular coupling in the right rat sensory cortex. CSD or tetrodotoxin in left cortex reduced the right cortical spontaneous spike rate by 36% and 45%, respectively. Baseline CBF in the right cortex was unaffected by a left-sided CSD, but decreased by 12% for left cortical application of tetrodotoxin. This suggested dissociation between spontaneous spiking activity and basal CBF. Left in-fraorbital nerve stimulation evoked local field potentials in right cerebral cortex that were reduced in amplitude by 19% for left CSD and by 23% for left tetrodotoxin application. The corresponding declines in the evoked CBF responses were 42% for CSD and 23% for tetrodotoxin. Vascular reactivity to adenosine remained unchanged in right cortex. Thus, transhemispheric diaschisis produced a pronounced decrease in the spontaneous spike rate accompanied by no reduction or a small reduction in basal CBF, and an attenuation in amplitudes of evoked synaptic responses and corresponding rises in CBF. The findings suggest that disturbed neurovascular coupling may contribute to the disturbance in brain function in acute transhemispheric diaschisis.
 ...
PMID:Impaired neurovascular coupling by transhemispheric diaschisis in rat cerebral cortex. 1524 Nov 79

Cortical application of KCl has previously been shown to induce tolerance to a subsequent episode of cerebral ischemia. KCl triggers recurrent episodes of cortical spreading depression and produces a small lesion at the cortical application site. To determine whether a cortical lesion alone is sufficient to induce tolerance to ischemia, the authors used 5-mol/L NaCl to precondition rat brain 3 days before permanent occlusion of the middle cerebral artery. NaCl produced a small lesion at the application site without evoking cortical spreading depression. Preconditioning with 5-mol/L NaCl significantly attenuated the decrease in CBF after middle cerebral artery occlusion and reduced the volume of cortical infarction by 35%. The results show that a small cortical lesion, by itself, is sufficient to induce tolerance to ischemia.
 ...
PMID:Induction of tolerance to focal ischemia in rat brain: dissociation between cortical lesioning and spreading depression. 1552 17


<< Previous 1 2 3 4 5 6 7 8 Next >>