Reduced carotid artery blood flow of spontaneously hypertensive rats is unaffected by aging from 20 weeks (young adulthood) to 65 weeks (upper middle age) (LB690)

Abstract

The objective of this study was to quantify blood flow (using a perivascular flowprobe) and pressure (using a catheter‐tip transducer) in the common carotid artery (CCA) of anesthetized young adult (~20 week old) and upper middle aged (~65 week old) Wistar Kyoto rats (WKY) and Spontaneously Hypertensive rats (SHR). In young adult SHR vs. WKY, mean (172±10 vs. 82±2 mmHg), systolic (198±13 vs. 92±4), diastolic (151±9 vs. 72±5), and pulse pressure (48±5 vs. 20±2), and heart rate (371±12 vs. 277±19 beats/min), were each elevated (p<0.01). In SHR, aging had no effect on these pressure parameters, or heart rate; whereas, in WKY, aging was associated with a significant increase in pulse pressure (31±1 mmHg; p=0.04) but no other pressure parameter. Mean (4.94±0.29 vs. 3.80±0.54 ml/min), maximum systolic (11.58±1.08 vs. 19.00±2.18), and minimum diastolic blood flow (0.62±0.73 vs. 1.90±0.34) were each reduced in young adult SHR vs. WKY (p<0.05), while flow pulsatility was no different (3.23±0.73 vs. 3.43±0.44). Aging had no effect on these flow parameters in either SHR or WKY. Together, these data demonstrate that CCA blood flow is >20% reduced in young adult SHR, and that this reduction is neither exacerbated nor attenuated at upper middle age. Given the important contribution of the internal branches of the CCAs to the total perfusion of the brain, these findings may be of pathophysiological and clinical relevance.Grant Funding Source: Supported by NSERC Canada