We measured brachial and femoral artery flow velocity in eight subjects and peroneal and median muscle sympathetic nerve activity (MSNA) in five subjects during tilt testing to 40°. Tilt caused similar increases in MSNA in the peroneal and median nerves. Tilt caused a fall in femoral artery flow velocity, whereas no changes in flow velocity were seen in the brachial artery. Moreover, with tilt, the increase in the vascular resistance employed (blood pressure/flow velocity) was greater and more sustained in the leg than in the arm. The ratio of the percent increase in vascular resistance in leg to arm was 2.5:1. We suggest that the greater vascular resistance effects in the leg were due to an interaction between sympathetic nerve activity and the myogenic response.
|Original language||English (US)|
|Journal||American Journal of Physiology - Heart and Circulatory Physiology|
|Issue number||1 50-1|
|State||Published - 2001|
All Science Journal Classification (ASJC) codes
- Cardiology and Cardiovascular Medicine
- Physiology (medical)