Vasoconstricting Effect of Angiotensin II in Human Hand Veins: Influence of Aging, Diabetes Mellitus and Hypertension.

Abstract

We examined human hand veins to determine whether venoconstricting response to angiotensin II (Ang II) and noradrenaline (NA) was influenced by aging or such diseases as diabetes mellitus (DM) and hypertension (HT). Twenty healthy male subjects (20-73 years), and 8 male patients with non-insulin-dependent DM and 8 male patients with essential HT were included in this study. A constant dose (50 ng/min) of Ang II or increasing dose (2-256 ng/min) of NA was infused into the dorsal hand vein and its diameter was measured using a linear variable differential transformer. The constant infusion of Ang II caused rapid desensitization or tachyphylaxis. The venoconstriction by Ang II in the 8 elderly subjects (58 to 73 years) was significantly (p<0.05) larger than that in the 8 young subjects (20 to 36 years) from 6 to 18 min after the start of the infusion (after 6 min: 63.6+/-11.6 (mean+/-SD)% vs. 39.9+/-20.8%, 12 min: 34.0+/-11.9% vs. 12.0+/-12.0%). However, the venoconstriction by Ang II in the patients with DM or HT was not significantly different from that in the 9 age-matched control subjects. No significant difference in venoconstrictor response to NA was observed between the young and elderly subjects, nor between the control subjects and the patients with DM or HT. These findings indicated that venoconstrictor response to Ang II might be greater in the elderly but might not be influenced by DM nor HT.

Comparison of Inhibitory Effects of Irbesartan and Atorvastatin Treatment on the Renin Angiotensin System (RAS) in Veins: A Randomized Double‐Blind Crossover Trial in Healthy Subjects

“…During Ang II infusion, measurements were taken every 3 minutes by cuff inflation for 1 minute. Based on a study recently published, 12 we chose 50 ng/min for the dose of continuous Ang II infusion because this dose induces a reproducible constrictor response with negligible changes in blood pressure or pulse rate. After a washout period of at least 20 minutes, increasing doses of the α 1 -adrenoceptor-agonist phenylephrine (47-1500 ng/min) were infused until a stable level of venous preconstriction of 20% vein size was reached.…”

Statin Treatment in Hypercholesterolemic Men Does Not Attenuate Angiotensin II-Induced Venoconstriction

“…The linear variable differential transducer (LVDT) technique is a useful approach to assess the influences of drugs in peripheral veins [7]–[9]. We inserted a 25-gauge needle in a suited dorsal hand vein.…”

“…Then, we infused a constant angiotensin II dose for 24 minutes. Based on an earlier study [9] we applied 50 ng/min angiotensin II because this dose induces a reproducible constrictor response with negligible systemic blood pressure or heart rate changes. During angiotensin II infusion, we obtained LVDT measurements every 3 minutes by inflating the brachial cuff to 40 mm Hg for 1 minute.…”

From Mitochondria to Disease: Role of the Renin-Angiotensin System

“…However, under conditions associated with RAS overactivation, including hypertension, diabetes [90, 91] and aging [92,93,94,95], dysregulation of Ang-II-dependent ROS generation may become a significant contributor to cell oxidation and tissue damage (fig. 2).…”