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Acute shifts in baroreflex control of renal sympathetic nerve activity induced by REM sleep and grooming in rats
Author(s) -
Nagura Satsuki,
Sakagami Tamaki,
Kakiichi Ai,
Yoshimoto Misa,
Miki Kenju
Publication year - 2004
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2004.064527
Subject(s) - baroreflex , medicine , anesthesia , phenylephrine , blood pressure , heart rate
The present study aimed to determine the impact of REM sleep and grooming on the baroreflex stimulus–response curve for renal sympathetic nerve activity (RSNA). At least 3 days before study, Wistar female rats ( n = 12) were chronically implanted with catheters to measure systemic arterial pressure ( P a ) and to intravenously infuse vasoactive drugs. In addition, electrodes were placed for measurements of RSNA, electroencephalogram, trapezius electromyogram and electrocardiogram. The baroreflex curve for RSNA was determined by changing P a using rapid intravenous infusions of phenylephrine and nitroprusside and then fitted to an inverse sigmoid function curve. REM sleep induced a vertical suppression of the P a –RSNA baroreflex curve, which was characterized by significant decreases in the maximum response (by 72.0%, P < 0.05) and the maximum gain (by 4.02% mmHg −1 , P < 0.05) compared with NREM sleep level. Grooming shifted the P a –RSNA baroreflex curve upward and to the right, which was associated with increases in the maximum response (by 45.2%, P < 0.05), the minimum response (by 20.7%, P < 0.05) and the pressure at the centring point (by 11.1 mmHg, P < 0.05). These data suggest that the P a –RSNA baroreflex curve was shifted acutely and differently in a state‐dependent manner during natural sleep and wake cycle in rats.