Effect of sleep/wake state on arterial blood pressure in genetically identical mice

Genetic determinants may contribute to the large variability inarterial blood pressure responses to changes in sleep/wake state inhumans. In this study, we developed techniques to examine therelationship between sleep/wake state and mean arterial pressure (MAP)in unrestrained, genetically identical mice (C57BL/6J;n = 9). The left common carotid arterywas catheterized, and arterial blood gases were analyzed 24-48 hpostsurgery to verify normal respiratory and metabolic function. Theanimals were then allowed to cycle naturally through sleep/wake statesover a 3- to 4-h period while continuous polysomnography and arterialpressure measurements were made. The MAP decreased fromquiet wakefulness to non-rapid-eye-movement sleep (9.8 ± 1.3 mmHg;P < 0.001) and further decreasedfrom non-rapid-eye-movement to rapid-eye-movement sleep (9.7 ± 1.8 mmHg; P < 0.001). We conclude thatthe inbred strain of C57BL/6J mice exhibits significant and consistentchanges in MAP related to sleep/wake state. Future studies can compare responses in this strain of mice with those in other inbred or transgenic mice to determine whether specific genes regulate arterial blood pressure responses to sleep/wake state.