The Ventrolateral Medulla and Sympathetic Regulation of Arterial Pressure

The ventrolateral medulla plays a critical role in the regulation of arterial blood pressure, mainly by regulating sympathetic nerve activity to cardiovascular targets such as the heart and blood vessels. This chapter focuses on the rat as an experimental model and discusses how different regions of the ventrolateral medulla, which are organized into semicontinuous columns, maintain basal sympathetic nerve activity to vascular targets in health and in diseases such as hypertension. The chapter emphasizes the importance of sympathoexcitatory neurons in the rostral ventrolateral medulla, and neurons in the caudal ventrolateral medulla that inhibit them, in the short term regulation of arterial pressure through effects on sympathetic reflexes. The chapter summarizes the extensive body of anatomical and physiological information about these neurons and highlights the on-going pursuit to better understand how these critical neurons are regulated in normotensive and hypertensive states.