Role of mutation of the circadian clock gene Per2 in cardiovascular circadian rhythms
- Vukolic, Ana Department of Medicine/Physiology, University of Fribourg, Switzerland
- Antic, Vladan Department of Medicine/Physiology, University of Fribourg, Switzerland
- Vliet, Bruce N. Van Memorial University of Newfoundland, St John's, Canada
- Yang, Zhihong Department of Medicine/Physiology, University of Fribourg, Switzerland
- Albrecht, Urs Department of Medicine/Physiology, University of Fribourg, Switzerland
- Montani, Jean-Pierre Department of Medicine/Physiology, University of Fribourg, Switzerland
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2010
Published in:
- American Journal of Physiology Regulatory, Integrative and Comparative Physiolology. - 2010, vol. 298, no. 3, p. R627-R634
English
Alterations in the circadian blood pressure pattern are frequently observed in hypertension and lead to increased cardiovascular morbidity. However, there are no studies that have investigated a possible implication of the Period2 gene, a key component of the molecular circadian clock, on the circadian rhythms of blood pressure and heart rate. To address this question, we monitored blood pressure, heart rate and locomotor activity 24h a day by telemetry in mice carrying a mutation in the Period2 gene and in wild type control mice. Under a standard 12h/12h light-dark cycle mutant mice showed a mild cardiovascular phenotype with an elevated 24h heart rate, a decreased 24h diastolic blood pressure and an attenuation of the dark-light difference in blood pressure and heart rate. Locomotor activity was similar in both groups and did not appear to explain the observed hemodynamic differences. When mice were placed under constant darkness during 8 consecutive days, wild type mice maintained 24h rhythms whereas there was an apparent progressive loss of 24h rhythm of blood pressure, heart rate and locomotor activity in mutant mice. However, a chi-square periodogram revealed that circadian rhythms were preserved under complete absence of any light cue, but with shorter periods by about 40 min, leading to a cumulative phase shift towards earlier times of about 5h and 20 min by the end of the 8th day. When heart rate, mean arterial pressure and activity were recalculated according to the endogenous circadian periods of each individual mouse, the amplitudes of the circadian rhythms ("subjective night"-"subjective day" differences) were maintained for all variables studied. Our data show that mutation of the Period2 gene results in an attenuated dipping of blood pressure and heart rate during both light-dark cycles and constant darkness, and in shorter circadian periods during constant darkness.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Médecine, Département de Biologie
- Language
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- English
- Classification
- Biological sciences
- License
- License undefined
- Identifiers
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- RERO DOC 17289
- DOI 10.1152/ajpregu.00404.2009
- Persistent URL
- https://folia.unifr.ch/unifr/documents/301478
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