scholarly journals Resistance of Optogenetically Evoked Motor Function to Global Ischemia and Reperfusion in Mouse in Vivo

2013 ◽  
Vol 33 (8) ◽  
pp. 1148-1152 ◽  
Author(s):  
Yicheng Xie ◽  
Shangbin Chen ◽  
Eitan Anenberg ◽  
Timothy H Murphy

Recently we have shown that despite reperfusion, sensory processing exhibits persistent deficits after global ischemia in a mouse in vivo model. We now address how motor output, specifically cortically evoked muscle activity, stimulated by channelrhodopsin-2 is affected by global ischemia and reperfusion. We find that the light-based optogenetic motor map recovers to 80% within an hour. Moreover, motor output recovers relatively faster and more completely than the sensory processing after 5-minute period of global ischemia. Our results suggest a differential sensitivity of sensory and motor systems to the effects of global ischemia and reperfusion that may have implications for rehabilitation.

2003 ◽  
Vol 52 (0) ◽  
pp. s23-s24 ◽  
Author(s):  
C. Marzocca ◽  
A. Vannacci ◽  
S. Cuzzocrea ◽  
D. Salvemini ◽  
P. F. Mannaioni ◽  
...  

2006 ◽  
Vol 84 (6) ◽  
pp. 611-615 ◽  
Author(s):  
Saverio Dragoni ◽  
Giuseppe Di Stolfo ◽  
Silvia Sicuro ◽  
Monica Lisi ◽  
John D. Parker ◽  
...  

Animal studies have shown that, as compared with unrestricted reperfusion, exposure to brief periods of controlled ischemia (postconditioning) at the end of a prolonged ischemia reduces the extent of tissue damage. We set out to test whether postconditioning can prevent endothelial dysfunction induced by ischemia and reperfusion in a human in vivo model. Ten healthy young non-smoking volunteers were enrolled in this cross-over, controlled, investigator-blinded study. Subjects were exposed to 15 min of forearm ischemia followed by either unrestricted reperfusion or postconditioning (3 periods of 20 s of ischemia separated by 10 s of reperfusion). Endothelium-dependent flow-mediated dilation (FMD) was measured at the level of the radial artery before and after ischemia (with or without postconditioning). Forearm ischemia blunted FMD in both study visits (unrestricted reperfusion visit: before ischemia, 7.7% ± 1.3%; after ischemia, 2.5% ± 1.4%; and postconditioning visit: before, 7.3% ± 1.2%; after, 2.6 ± 1.6%; P < 0.05 for both, P = not significant (NS) between visits). In contrast with data from animal studies, postconditioning (20 s ischemia – 10 s reperfusion repeated 3 times) does not limit post-ischemic endothelial dysfunction in this human in vivo model. Further human studies are necessary to evaluate other reperfusion protocols in an attempt to limit post-ischemic tissue damage.


Author(s):  
Chantal McMahon ◽  
David P Kowalski ◽  
Alexander J Krupka ◽  
Michel A Lemay

We explored the relationship between population interneuronal network activation and motor output in the adult, in-vivo, air stepping, spinal cat. By simultaneously measuring the activity of large numbers of spinal interneurons, we explored ensembles of coherently firing interneurons and their relation to motor output. Additionally, the networks were analyzed in relation to their spatial distribution along the lumbar enlargement for evidence of localized groups driving particular phases of the locomotor step cycle. We simultaneously recorded hindlimb EMG activity during stepping and extracellular signals from 128 channels across two polytrodes inserted within lamina V-VII of two separate lumbar segments. Results indicated that spinal interneurons participate in one of two ensembles that are highly correlated with the flexor or the extensor muscle bursts during stepping. Interestingly, less than half of the isolated single units were significantly unimodally tuned during the step cycle while >97% of the single units of the ensembles were significantly correlated with muscle activity. These results show the importance of population scale analysis in neural studies of behavior as there is a much greater correlation between muscle activity and ensemble firing than between muscle activity and individual neurons. Finally, we show that there is no correlation between interneurons' rostrocaudal locations within the lumbar enlargement and their preferred phase of firing or ensemble participation. These findings indicate that spinal interneurons of lamina V-VII encoding for different phases of the locomotor cycle are spread throughout the lumbar enlargement in the adult spinal cord.


2002 ◽  
Vol 22 (7) ◽  
pp. 821-834 ◽  
Author(s):  
Nicolas Blondeau ◽  
Inger Lauritzen ◽  
Catherine Widmann ◽  
Michel Lazdunski ◽  
Catherine Heurteaux

Lysophospholipids (LPLs) are important intermediates in the synthesis and degradation of membrane phospholipids. Here we show that certain LPLs, particularly lysophosphatidylcholine and lysophosphatidylinositol, prevent neuronal death both in an in vivo model of transient global ischemia and in an in vitro model of excitotoxicity using primary cultures of cerebellar granule cells exposed to high extracellular concentrations of glutamate (20–40 μmol/L). The intravenous injection of lysophosphatidylcholine or lysophosphatidylinositol at a concentration of 200 nmol/kg induced a survival of CA1 pyramidal neurons as high as approximately 95%, even when the treatment was started 30 minutes after 15-minute global ischemia. In contrast, lysophosphatidic acid induced no protection. This work also provides evidence that a pretreatment with lysophosphatidylcholine or lysophosphatidylinositol (200 nmol/kg) injected as long as 3 days before a severe 6-minute ischemia provided a potent tolerance against neurodegeneration. Neuroprotection was also observed in in vitro experiments with LPLs. Taken together, in vivo and in vitro data suggest a potential therapeutic use of LPLs as antiischemic compounds. The potential role of 2P-domain K+ channels as targets of LPLs in this potent neuroprotective effect is discussed.


1996 ◽  
Vol 734 (1-2) ◽  
pp. 86-90 ◽  
Author(s):  
Mamoru Shibata ◽  
Nobuo Araki ◽  
Junichi Hamada ◽  
Takahiro Sasaki ◽  
Kunio Shimazu ◽  
...  

2011 ◽  
Vol 26 (1) ◽  
pp. 64-67 ◽  
Author(s):  
T. Toffanin ◽  
F. Nifosì ◽  
H. Follador ◽  
A. Passamani ◽  
F. Zonta ◽  
...  

AbstractSeveral preclinical studies have demonstrated neuronal effects of glucocorticoids on the hippocampus (HC), a limbic structure with anterior–posterior anatomical and functional segmentation. We propose a volumetric magnetic resonance imaging analysis of hippocampus head (HH), body (HB) and tail (HT) using Cushing's disease (CD) as model, to investigate whether there is a differential sensitivity to glucocorticoid neuronal damage in these segments. We found a significant difference in the HH bilaterally after 12 months from trans-sphenoidal surgical selective resection of the adrenocorticotropic hormone (ACTH)-secreting pituitary micro-adenomas. This pre–post surgery difference could contribute to better understand the pathopysiology of CD as an in vivo model for stress-related hypercortisolemic neuropsychiatric disorders.


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