Depressor area within caudal ventrolateral medulla of the rat does not correspond to the A1 catecholamine cell group

In an attempt to confirm reports of a depressor area corresponding to the location of the A1 noradrenaline cell group within the caudal ventrolateral medulla, cardiovascular responses associated with focal electrical stimulation of that region of the brainstem were measured. Depressor responses were reliably elicited by stimulation of an area immediately dorsomedial to the rostral third of the A1 cell group, but not by stimulation of the A1 group itself.