Asynchronism of the recovery of baroreflex sensitivity, blood pressure, and consciousness from anesthesia in rats.
Anesthesia inhibits arterial baroreflex functions such as baroreflex sensitivity (BRS). The main objective of the present study was to determine the time course of BRS recovery from anesthesia and to determine whether BRS recovery is synchronous with the recovery of consciousness and blood pressure (BP). Experiments were performed in male Sprague-Dawley rats using different commonly used anesthetics at routine doses through intraperitoneal administration: (1) diazepam/ketamine, a mixture of diazepam (5 mg/kg) and ketamine (50 mg/kg); (2) chloral hydrate (0.3 g/kg); (3) sodium pentobarbital (30 mg/kg); and (4) urethane (1.0 g/kg). The anesthetic state, evaluated by algesthesia and cornea reflex, was maintained for 1-2.5 hours. The BRS, assessed by intravenous injection of phenylephrine, was inhibited rapidly and dramatically, with maximum depressions of 51%-80%. The BRS recovery time was approximately 5 hours for diazepam/ketamine, chloral hydrate, and pentobarbital, but more than 24 hours for urethane. Compared with BRS inhibition, BP reduction was less pronounced by 8% (not significant) for diazepam/ketamine and by 12%-30% for the others. The BP recovery time was approximately 2 hours, with the exception of chloral hydrate (>6 hours). In conclusion, after anesthesia, BRS inhibition is more obvious than BP reduction, and the recovery of BRS lags behind the recovery of consciousness or BP.
Yi-Ming
Wuliya
W
Department of Pharmacology, Second Military Medical University, Shanghai, China.
Shu
He
H
Miao
Chao-Yu
CY
Shen
Fu-Ming
FM
Jiang
Yuan-Ying
YY
Su
Ding-Feng
DF
D000762:Anesthesia Recovery Period; D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D017704:Baroreflex / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000777:Anesthetics