Effects of propofol on noradrenaline release from the locus coeruleus in rabbits / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of propofol on the release of noradrenaline ( NE) from the locus coeruleus in the brain of rabbits trying to elucidate the central mechanism of the cardiovascular inhibition induced by propofol.Methods Nine healthy male New Zealand rabbits weighing 2.0-2.5 kg were used in this study. A trocar (0.8 mm in diameter) was inserted into locus coeruleus using the stereotactic technique and fixed. Four days later push-pull perfusion of the brain was performed. 37℃ artificial cerebrospinal fluid (aCSF) was infused through the trocar at 0.1 ml?min-1 . A loading dose of propofol 2 mg?kg-1 was given i.v. followed by continuous infusion at 150 ?g?kg-1?min-1 for 30 min. The experiment was concluded at 20 min after propofol infusion. The perfusate having passed through the locus coeruleus was collected before and every 10 min during and after infusion. The NE concentration of the perfusate was measured by high performance liquid chromatography. Results The NE concentration of the perfusate from locus coeruleus significantly decreased after the loading dose and during the infusion of propofol and reached its bottom level at 10 min after loading dose. The maximal decrease was 75.5% [from (15.9 ? 3.2) pg??l-1 to (3.9?0.5) pg ? ?l-1]. Conclusion Intravenous propofol decreases the NE concentration in locus coeruleus. The cardiovascular inhibition induced by propofol may partly be explained by this central mechanism.