title: Cardiovascular response to stress after middle cerebral artery occlusion in rats.
abstract: Previously, we have shown cardiovascular and autonomic disturbances in male Wistar rats following middle cerebral artery occlusion (MCAO). Using this model, neurochemical changes, that were maximal at 3-5 days and subsiding by day 10, were observed unilaterally in the insular cortex and amygdala. The amygdalar neurochemical changes may be related to the stroke-induced cardiovascular disturbances, since the amygdala is critical in mediating the cardiovascular responses to stress. We examined the cardiovascular responses to intermittent and continuous noise and air-jet stimulation in male Wistar rats on days 2-10 after right-sided MCAO or sham MCAO. Compared to the sham MCAO rats, intermittent noise elicited significant tachycardiac responses on days 5 and 7 after stroke. Air-jet stimulation also elicited a significant tachycardic response on day 5, whereas continuous noise produced significant tachycardiac and pressor responses at days 5 and 7, respectively, in the MCAO rats compared to the control rats. Analyses on the heart rate variability using fast Fourier transformation revealed significant increases in the normalized mid-frequency spectral power on day 7 for intermittent noise and air-jet stimulation, suggesting increases in the sympathetic activity. These results indicate a time-course of exaggerated cardiovascular responses to stress and suggest a state of susceptibility to cardiac perturbations in rats following stroke.
authors.affiliation: John P. Robarts Research Institute and Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada.
authors.forename: R T
authors.initials: RT
authors.lastname: Cheung
authors.forename: V C
authors.initials: VC
authors.lastname: Hachinski
authors.forename: D F
authors.initials: DF
authors.lastname: Cechetto
mesh_terms: D000679:Amygdala / Q000503:physiopathology; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology*; D002536:Cerebral Arteries / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology; D004562:Electrocardiography; D005583:Fourier Analysis; D006339:Heart Rate / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological / Q000503:physiopathology*