Neurons (presumably A1-cells) projecting from the caudal ventrolateral medulla to the region of the supraoptic nucleus respond to baroreceptor inputs in the rabbit.

Extracellular recordings were made in the caudal ventrolateral medulla from 29 neurons that could be antidromically activated from the region of the supraoptic nucleus in the rabbit. The median axonal conduction velocity was 0.8 m/s. Of 15 cells tested only one did not respond to some form of baroreceptor input. Fourteen were inhibited by experimentally increasing arterial pressure and 8 were excited by decreasing arterial pressure. Stimulation of the aortic depressor nerve decreased the discharge rate of 8 out of 12 cells tested. The location and projections of these neurons suggest that they were A1 noradrenaline-synthesizing cells.