OBJECTIVE: To determine the suitability of a new logistic curve fitting procedure to measure the diurnal rates of transition from the active to the asleep periods separately. METHOD: We applied this method to 24-h telemetry recordings of systolic, mean, diastolic arterial pressure (SAP, MAP, DAP, respectively), heart rate (HR) and locomotor activity of normotensive Sprague-Dawley rats (SDR) and spontaneously hypertensive rats (SHR). RESULTS: There was a similar pattern of higher awake and lower sleep values (16 +/- 1 mmHg SAP, 77 +/- 2 bpm HR and 40 +/- 2 units activity) in SHR. In SDR, awake-asleep differences were less for SAP (9 +/- 1 mmHg) but similar for HR (83 +/- 2 bpm). In SHR, while the blood pressure patterns were symmetrical, the rate of rise in activity and HR during arousal was more rapid than the rate of decline during the dark to light transition. By contrast in SDR, the arousal rate of increase in blood pressure and HR was much less than the rate of decline. Thus SHR have an exaggerated arousal surge in DAP compared with SDR. Double logistic provides a better fit than Cosinor or square wave and better estimates of day-night differences than partial Fourier. CONCLUSIONS: Analysis of 24-h recordings by a new logistic curve method reveals distinct asymmetric circadian patterns of cardiovascular and activity changes in rats. The greater surge in arousal blood pressure in SHR is not associated with differences in HR or activity changes and may be inherent to the underlying mechanisms contributing to the hypertension in SHR.
OBJECTIVE: To determine the suitability of a new logistic curve fitting procedure to measure the diurnal rates of transition from the active to the asleep periods separately. METHOD: We applied this method to 24-h telemetry recordings of systolic, mean, diastolic arterial pressure (SAP, MAP, DAP, respectively), heart rate (HR) and locomotor activity of normotensive Sprague-Dawley rats (SDR) and spontaneously hypertensiverats (SHR). RESULTS: There was a similar pattern of higher awake and lower sleep values (16 +/- 1 mmHg SAP, 77 +/- 2 bpm HR and 40 +/- 2 units activity) in SHR. In SDR, awake-asleep differences were less for SAP (9 +/- 1 mmHg) but similar for HR (83 +/- 2 bpm). In SHR, while the blood pressure patterns were symmetrical, the rate of rise in activity and HR during arousal was more rapid than the rate of decline during the dark to light transition. By contrast in SDR, the arousal rate of increase in blood pressure and HR was much less than the rate of decline. Thus SHR have an exaggerated arousal surge in DAP compared with SDR. Double logistic provides a better fit than Cosinor or square wave and better estimates of day-night differences than partial Fourier. CONCLUSIONS: Analysis of 24-h recordings by a new logistic curve method reveals distinct asymmetric circadian patterns of cardiovascular and activity changes in rats. The greater surge in arousal blood pressure in SHR is not associated with differences in HR or activity changes and may be inherent to the underlying mechanisms contributing to the hypertension in SHR.
Authors: Lynette Pretorius; Xiao-Jun Du; Elizabeth A Woodcock; Helen Kiriazis; Ruby C Y Lin; Silvana Marasco; Robert L Medcalf; Ziqiu Ming; Geoffrey A Head; Joon Win Tan; Nelly Cemerlang; Junichi Sadoshima; Tetsuo Shioi; Seigo Izumo; Elena V Lukoshkova; Anthony M Dart; Garry L Jennings; Julie R McMullen Journal: Am J Pathol Date: 2009-08-13 Impact factor: 4.307
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Authors: Geoffrey A Head; Nick Andrianopoulos; Barry P McGrath; Catherine A Martin; Melinda J Carrington; Elena V Lukoshkova; Pamela J Davern; Garry L Jennings; Christopher M Reid Journal: PLoS One Date: 2014-03-25 Impact factor: 3.240
Authors: H Rodríguez-Angulo; J Toro-Mendoza; J Marques; R Bonfante-Cabarcas; A Mijares Journal: Braz J Med Biol Res Date: 2013-01-11 Impact factor: 2.590