1,721,019 research outputs found
Pial microvscular effects of querceting during transient bilateral common carotid artery occlusion in rats
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Remodeling of rat pial microcirculation after transient middle cerebral artery occlusion
No full textPIAL ARTERIOLAR VASOMOTION CHANGES DURING CORTICAL ACTIVATION IN RATS
No full textThe oscillatory pattern of pial arterioles, i.e. vasomotion, has been described since early 1980s, but the impact of neural activation on such oscillations has never been formally examined. Sciatic nerve stimulation, a well characterized model for studying neurovascular coupling (NVC), leads to a neural activity-related increase of pial arteriolar diameter in the contralateral hindlimb somatosensory cortex. Exploiting such an experimental model, the aim of the present study was to explore vasomotion and its changes during NVC with a novel analytical approach. Indeed, to characterize oscillations, we evaluated the total spectral power in the range 0.02-2.00 Hz and subdivided this frequency interval into seven 50% overlapping frequency bands. Results indicated that only arterioles overlying the stimulated hindlimb cortex showed a significant increase of total power, unlike arterioles overlaying the whisker barrel cortex, used as control for the vascular response specificity. The total power increase was sustained mainly by marked increments in the low frequency range, with two peaks at 0.03 and 0.08 Hz, and by a wide increase in the high frequency range (0.60-2.00 Hz) in the averaged spectrum. These activity-related spectral changes suggest: (i) that it is possible to assess the vascular responses by using total power; (ii) the existence of at least three distinct mechanisms involved in the control of NVC, two with a feedback frequency loop in the low frequency range and another one in the high range; (iii) a potential involvement of vasomotion in NVC. Moreover, these findings highlight the oscillatory nature of the mechanisms controlling NVC
Effects of Catechin on cerebral arteriole vasomotion in spontaneously hypertensive rats
No full textStudies in humans have found consumption of certain flavanoid-containing foods to be associated with improvement in endothelial function and with reduction in blood pressure. In particular, catechin, a natural phenol contained in cocoa and green tea, appears to play a crucial role in the prevention of cardiovascular diseases reducing the systemic arterial blood pressure. The aim of the present study was to in vivo investigate the effects of oral administration of catechin on pial arteriolar rhythmic diameter changes in SHR in comparison with normotensive rats. Catechin was orally administered to SHR for 2 months at the dosage of 30 mg/kg b.w. The pial microcirculation was visualized by fluorescence microscopy. The vessel diameter and rhythmic variations in diameter were evaluated with computer-assisted method. Moreover, the pial arterioles were classified by Strahler scheme in five orders. On 30 min of recordings was performed the Spectral analysis in order to evaluate different frequency components: the first two in the ranges 0.005-0.0095 Hz and 0.0095-0.021 Hz (endothelial activity), the second in the range 0.021-0.052 Hz (neurogenic activity), the third in the range 0.052-0.145 Hz (myogenic activity), finally, the fourth and the fifth in the ranges 0.145-0.6 Hz (respiratory activity) and 0.6-3.0 Hz (heart beat), respectively. The data indicate that SHR treated with catechin presented an increase in the amplitude frequency components related to endothelial activity that in untreated SHR were markedly reduced. In conclusion, the catechin treatment induces the recovery of endothelial activity in SHR where this frequency component was seriously compromised compared to normotensive rats
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