Role of adenosine A1 receptor within nucleus tractus solitarii in dexmedetomidine-induced increase in baroreflex sensitivity in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of A1 adenosine receptor ( A1 AR) within the nucleus tractus solitarii ( NTS ) in dexmedetomidine-induced increase in baroreflex sensitivity ( BRS ) in rats. Methods Thirty-two clean-grade healthy male Sprague-Dawley rats, weighing 240-280 g, were divided in-to 4 groups ( n=8 each) using a random number table method: control group ( group C) , solvent control group ( group S) , dexmedetomidine group ( group D) , and dexmedetomidine plus 8-cyclopentyl-1,3-diprop-ylxanthine (DPCPX, a highly selective A1AR blocker) group (group DD). After the rats were anesthe-tized, 1 μl drug liquid was injected into the right NTS with a brain stereotaxic apparatus. Oneμl normal sa-line was injected into the right NTS in C and D groups, 1 μl dimethyl sulfoxide in group S, and 1 μl DPCPX in group DD. After catheters were implanted into the femoral vein, dexmedetomidine was intrave-nously infused as a bolus of 100μg/kg over 15 min followed by an infusion of 50μg·kg-1 ·h-1 for 105 min in D and DD groups. The equal volume of normal saline was given instead of dexmedetomidine in C and S groups. BRS was measured using phenylephrine immediately before intravenous infusion (T0) and at 60 and 120 min after beginning of infusion ( T1,2 ) . Results Compared with C and S groups, the BRS was signifi-cantly increased at T1,2 in D and DD groups ( P＜0. 05) . Compared with group D, the BRS was significantly decreased at T1,2 in group DD ( P＜0. 05) . Conclusion A1 AR within the NTS is involved in dexmedetomi-dine-induced increase in BRS in rats.