Plasma catecholamines and renin during operant blood pressure conditioning in baboons

Plasma catecholamines and renin activity were measured in baboons undergoing operant diastolic blood pressure conditioning. Pre-training baseline norepinephrine averged 364 pg/ml, epinephrine 253 pg/ml, dopamine 270 pg/ml, and renin activity 2.62 ng/ml/hr. During the training sessions, systolic blood pressure increased significantly 19 mmHg (15%), diastolic pressure 20 mmHg (30%), and heart rate 33 bpm (33%) compared with pre-session values. Also during the sessions, norepinephrine increased significantly by 253 pg/ml (48%) and epinephrine increased by 130 pg/ml (0.05<p<0.10), while plasma dopamine and renin activity did not change significantly. Plasma norepinephrine levels correlated positively with systolic and diastolic blood pressures in all baboons tested, in both baseline and training conditions. To the extent that plasma norepinephrine reflects sympathetic nervous system activity, these findings demonstrate an association between sympathetic activity and blood pressure in this hypertensive model.