Title of article :
Propofol Causes Consciousness Loss by Affecting GABA-A Receptor in the Nucleus Basalis of Rats
Author/Authors :
Xing, Yunlong Department of Plastic Surgery - China-Japan union Hospital of Jilin University, Changchun, China , Li, Kai Department of Anesthesiology - China-Japan union Hospital of Jilin University, Changchun, China , Jiao, Yuan Department of Anesthesiology - China-Japan union Hospital of Jilin University, Changchun, China , Li, Zinan Department of Anesthesiology - China-Japan union Hospital of Jilin University, Changchun, China
Abstract :
Objective. Propofol is a classical anesthetic and induces consciousness loss, and gamma-aminobutyric-acid-type-A (GABA-A)
receptor is its target. Righting reflex is associated with conscious response. The nucleus basalis (NB) acts as a major relay
between the reticular activating system and the frontal cortex (FC). Propofol may mediate righting reflex by affecting GABA-A
receptor in NB. Methods. Fifty male SD rats (250-350 g) were divided into parts I and II. In part I, 20 male SD rats were
randomly divided into control group (CG) and NB-lesion group (NG, ibotenic acid-induced NB lesion). In part II, 30 male SD
rats were treated with saline (0.9% NaCl, SG group), muscimol (a GABA-A receptor agonist, MG group), and gabazine
(a GABA-A receptor antagonist, GG group) in NB, respectively. Two weeks later, the activity of the rats was measured between
CG and NG groups. The rats were intravenously injected with propofol (50 mg/kg/h) to test the time of loss of righting reflex
(LORR) in all rats. When LORR occurred, the rats received single administration of propofol (12 mg/kg) to measure the time of
return of righting reflex (RORR). Electroencephalogram (EEG) activity of the frontal cortex (FC) was recorded. Results. The
numbers of NB neurons were reduced by 44% in the NG group compared to the CG group (p < 0:05) whereas the activity of
rats was reduced a little in the NG group when compared with the CG group, but the statistical difference was insignificant
(p > 0:05). The dose-response curve of propofol shifted to the left in the NG group, and the statistical difference for the time of
LORR was insignificant between the two groups (p > 0:05). However, the time of RORR and FC delta power increased in the
NG group compared with the CG group (p < 0:05). In part II, the time of RORR and FC powder increased in the MG group
when compared to the SG group while reverse results were observed in the GG group (p < 0:05). There was no significant
influence on the time of LORR and ED50 among the three groups (p > 0:05). Conclusions. The unilateral NB lesion increased
the recovery time and FC delta power, and the NB region might be involved in the emergence after propofol administration.
Propofol plays a crucial role for causing conscious loss by affecting GABA-A receptor in NB.
Keywords :
Propofol Causes , Consciousness Loss , Affecting GABA-A Receptor , Nucleus Basalis , Rats
