Effect of dexmedetomidine on long-term sensorimotor gating system after sevoflurane anaesthesia in neonatal rats

Abstract

Objective To evaluate the effect of dexmedetomidine on the long-term sensorimotor gating system after sevoflurane anaesthesia in neonatal rats. Methods One hundred forty-four clean-grade healthy male Sprague-Dawley rats, aged 4-6 days, weighing 8-15 g, were divided into 4 groups (n=36 each) using a random number table method: control group (group C), sevoflurane group (group S), dexmedetomidine plus sevoflurane group (group D+ S), and dexmedetomidine plus α2 receptor antagonist atipamezole plus sevoflurane group (group D+ A+ S). In group S, anesthesia was induced with 6% sevoflurane for 3 min and maintained with 2.1% sevoflurane, and the anesthesia time was 6 h in total.Dexmedetomidine 25 μg/kg was intraperitoneally injected in group D. In group D+ A+ S, dexmedetomidine 25 μg/kg and atipamezole 250 μg/kg were intraperitoneally injected, and the other treatments were similar to those previously described in group S. Twelve rats in each group were randomly selected after anesthesia and sacrificed, and blood samples were collected for determination of serum corticosterone concentrations by enzyme-linked immunosorbent assay.Twenty-four rats were randomly selected in each group, and prepulse inhibition (PPI) of startle test was performed at 70 days after birth.PPI rate (PP3%, PP6%, PP12%) was calculated.The serum corticosterone concentration was measured by restraint stress test on 80 days after birth. Results There was no significant difference in PP6% or PP12% among the four groups (P>0.05). Compared with group C, PP3% was significantly decreased, and the serum corticosterone concentration was increased after the end of anesthesia and during restraint stress test at 80 days after birth in S and D+ A+ S groups (P 0.05). Compared with group S, PP3% was significantly increased, and the serum corticosterone concentration was decreased after the end of anesthesia and during restraint stress test at 80 days after birth in group D (P 0.05). Compared with group D, PP3% was significantly decreased, and the serum corticosterone concentration was increased after the end of anesthesia and during restraint stress test at 80 days after birth in group D+ A+ S (P<0.05). Conclusion Dexmedetomidine can alleviate the damage to long-term sensorimotor gating system after sevoflurane anesthesia in neonatal rats, and the mechanism may be related to activating central α2 receptors and improving hypothalamic-pituitary-adrenal axis hyperfunction. Key words: Dexmedetomidine; Anesthetics, inhalation; Infant, newborn; Adolescent; Sensorimotor gating system