Figure 10

Baroreceptor unit response to phenylephrine injection (2 arrows at the beginning of A). Blood pressure increased approximately 6 s thereafter, during which time the unit deactivated in three steps (denoted by 3 arrow heads at the end of A and beginning of B), indicating at least 3 encoders in this unit. Complete deactivation occurred at the last arrow head, induced by injection of blood into the artery (starting immediately before the last arrow head) and re-activated as blood withdrawn. C is post-control.