Aim: 

To investigate whether leptin deficiency leads to derangements of the central autonomic and the baroreflex cardiac control in wakefulness (W), non-rapid-eye-movement (non-REM) sleep, and REM sleep.

Methods: 

Leptin-deficient B6.V-Lep^ob/OlaHsd obese mice (ob/ob, n = 6) and lean wild-type littermates (n = 10) were implanted with electrodes for discriminating wake-sleep states and a telemetric blood pressure transducer (TA11PA-C10, DSI). The cross-correlation function between the low-frequency (<0.8 Hz) fluctuations of heart period and those of systolic blood pressure was computed in episodes of W, non-REM sleep, and REM sleep of duration >60 s. The central autonomic and the baroreflex contribution to cardiac control were estimated from the minimum and maximum values of the cross-correlation function, respectively. The cardiac baroreflex gain (BRS) was estimated with the sequence technique. Data were analyzed with a 2-way analysis of variance and t-test and significance at p < 0.05.

Results: 

The interaction effect between the wake-sleep state and the genetic group was significant on all variables considered. The baroreflex contribution to cardiac control was lower in ob/ob than in wild-type mice, the difference being significant in W and non-REM sleep. In ob/ob mice, the central autonomic contribution to cardiac control was preserved during W, but was significantly lower than in wild-type mice during non-REM sleep and REM sleep. In ob/ob mice, BRS was significantly lower than in wild-type mice in each wake-sleep state.

Conclusion: 

These data indicate that congenital leptin deficiency disrupts the central autonomic and the baroreflex cardiac control in obese ob/ob mice. The results further support the view that due to the physiological impact of sleep on cardiovascular regulation, pathological derangements of the central autonomic and the baroreflex cardiac control may be masked or enhanced during specific wake-sleep states.