Propofol Modulates γ-Aminobutyric Acid–mediated Inhibitory Neurotransmission to Cardiac Vagal Neurons in the Nucleus Ambiguus

Abstract

Propofol may vary heart rate by modulating GABAergic neurotransmission to cardiac parasympathetic neurons. At clinically relevant concentrations (> or =1.0 microm), propofol facilitated GABAergic responses in cardiac vagal neurons by increasing decay time, which would increase inhibition of cardioinhibitory cardiac vagal neurons and evoke an increase in heart rate. At higher supraclinical concentrations (> or =50 microm), propofol inhibits GABAergic neurotransmission to cardiac vagal neurons, which would evoke a decrease in heart rate.