GABA_A receptors in the basal forebrain mediates emergence from propofol anaesthesia in rats

Abstract

Purpose

The aim of the current study was to explore the role of the basal forebrain (BF) in propofol anaesthesia.

Methods

In the present study, we observed the neural activities of the BF during propofol anaesthesia using calcium fibre photometry recording. Subsequently, ibotenic acid was injected into the BF to verify the role of the BF in propofol anaesthesia. Finally, to test whether GABA_A receptors in the BF were involved in modulating propofol anaesthesia, muscimol (GABA_A receptor agonist) and gabazine (GABA_A receptor antagonist) were microinjected into the BF. Cortical electroencephalogram (EEG), time to loss of righting reflex (LORR), and recovery of righting reflex (RORR) under propofol anaesthesia were recorded and analysed.

Results

The activity of BF neurons was inhibited during induction of propofol anaesthesia and activated during emergence from propofol anaesthesia. In addition, non-specifical lesion of BF neurons significantly prolonged the time to RORR and increased delta power in the frontal cortex under propofol anaesthesia. Next, microinjection of muscimol into the BF delayed emergence from propofol anaesthesia, increased delta power of the frontal cortex, and decreased gamma power under propofol anaesthesia. Conversely, infusion of gabazine accelerated emergence times and decreased EEG delta power.

Conclusions

The basal forebrain is involved in modulating frontal cortex delta activity and emergence from propofol anaesthesia. Additionally, the GABA_A receptors in the basal forebrain are involved in regulating emergence propofol anaesthesia.

Keywords:

• Propofol
• basal forebrain
• GABAA receptor
• emergence
• calcium fibre photometry recording
• cortical electroencephalogram

Acknowledgements

We thank Bao Fu from Department of Critical Care Medicine, Affiliated Hospital of Zunyi Medical University for kindly revising the manuscript.

Authors’ contributions

C L and B F completed data analysis and writing the manuscript. Y Z and T.

Y were responsible for design. L Z was responsible for calcium fibre photometry. S F and T L performed the behavioural tests and the electrophysiology recordings. All authors read and approved the final manuscript.

Ethics approval and consent to participate

All experimental and surgical procedures were approved by Committees on Investigations Involving Animals in Zunyi Medical University, China (grant number：2019(2)-289).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Availability of data and materials

The datasets generated and analysed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

The present study was supported by the National Natural Science Foundation of China (grant number: 81971298). This funding was used for the animal and material of the study.