Propofol decreases the excitability of cholinergic neurons in mouse basal forebrain via GABAA receptors

Propofol is an intravenous anesthetic that can active gamma-aminobutyric acid A (GABA(A)) receptors and generate sedative-hypnotic effects. Propofol has been widely applied clinically to achieve sedation comparable to sleep in humans. The basal forebrain (BF) is a brain region that plays an important role in sleep-wake regulation. Previous studies suggest that propofol affects the sleep-wake circuit via the BF; however, the mechanism remains elusive. In the current study we investigated the effects of propofol on the inherent properties of cholinergic neurons and their ability to convert excitatory inputs into spikes in mouse BF slices using whole-cell patch clamp recordings. Bath application of propofol (10 mu M) significantly elevated the threshold potentials (Vts), decreased the number of spikes in response to a depolarizing current injection, and augmented the inter-spike intervals (ISIs), energy barrier (Vts-Vrs), and absolute refractory periods (ARPs). These effects were eliminated by co-application of a GABA(A) receptor antagonist picrotoxin (50 mu M). Altogether, our results reveal that propofol decreases the excitability of cholinergic neurons in mouse BF via GABAA receptors.