• Activation of PPG neurons triggers increases in heart rate in mice. • PPG neurons do not provide a tonic sympathetic drive to the heart. • The tachycardic effect of systemic Ex-4 is not mediated by PPG neurons. • GLP-1 receptor activation has a sympathoexcitatory effect that increases heart rate. • Local activation of GLP-1R in the spinal cord is sufficient to elicit tachycardia.