Objective. To test the hypothesis of a possible role of the Panx1 (pannexin-1) mutation in changing the sleep — wake cycle. Material and methods. Continuous 24 h recording of the EEG and movement activity in Panx1 knockout and wild type mice was performed. Results and conclusion. A significant increase in wake percentage at the expense of a decrease in slow-wave sleep was found in knockout mice as compared to the control ones. The difference was especially pronounced during the 12-h dark period in the chamber. Also, an increase in the movement activity was clearly seen in knockout mice. The results are compared to a recent case-report of a Panx1 female patient with homozygote’s mutation in this gene. The role of Panx1 protein in normal as well as pathological physiology is discussed.