THE EFFECTS OF ACETAZOLAMIDE ON ARTERIAL-PRESSURE VARIABILITY DURING REM-SLEEP IN THE RAT

During rapid eye movement (REM) sleep, the arterial pressure (AP) unde rgoes large fluctuations in the rat, cat, and other mammals, including humans, and it has been suggested that this effect originates in the forebrain. In addition, acetazolamide (ACTZ), a carbonic anhydrase inh ibitor, is known to be effective in the treatment of central sleep apn ea or epilepsy. The aim of the present study was to analyze the effect s of ACTZ on EEG theta rhythm and AP variability during REM sleep in r ats. Treatment consisted of intraperitoneal injection of 5 mg of ACTZ in 0.5 mt of saline (n = 6) or 0.5 mt of vehicle alone (n = 6). We the n recorded and analyzed the mean AP (MAP) variations during different sleep phases, using a telemetric system. Our results show: 1) Signific ant decreases in the coefficient of variation of MAP, in the very-low frequency (0.025 - 0.225 Hz) component of the power spectral density o f the AP and in theta frequency in the electroencephalogram, were seen in the ACTZ-treated group during REM sleep compared with controls, wh ereas no significant difference was found between the two groups in no n-REM sleep. There was no significant difference in sleep duration, av erage MAP, and heart rate between the groups. Our data suggest that AC TZ may act asa stabilizing factor preventing AP fluctuations during RE M sleep. (C) 1998 Elsevier Science Inc.