Figure 9

Another baroreceptor unit in response to phenylephrine injection (indicated by the arrow in A). A and B, and C and D are in continuance with a 30 s elapse between B and C. Please note that after inactivated, the unit became active as blood pressure was lowered by withdrawal of blood from the femoral artery (about 20 ml) at the beginning of C. The unit was inactivated again by increasing the blood pressure by injection of the blood into the artery. Such activation and inactivation can be repeated.