Dayan Lior, Brill Silviu, Hochberg Uri, Jacob Giris
Pain Institute, Tel Aviv Medical Center and Sackler Faculty of Medicine, TAU, Tel Aviv, Israel.
Recanati Autonomic Dysfunction Center Tel Aviv Medical Center and Sackler Faculty of Medicine, TAU, Tel Aviv, Israel.
Clin Auton Res. 2016 Apr;26(2):141-7. doi: 10.1007/s10286-016-0345-y. Epub 2016 Feb 5.
Local vasoconstrictor reflexes, the vascular myogenic response (VMR) and the veno-arterial reflex (VAR) are necessary for the maintenance of regional blood flow and systemic arterial blood pressure during orthostatic stress. Their molecular mechanism is unknown. We postulated that adenosine is involved in the activation of these local reflexes.
This hypothesis was tested in 10 healthy male volunteers (age 29 ± 3 years, BMI 24 ± 1 kg/m(2)). We used veno-occlusive plethysmography method for the assessment of forearm arterial blood flow at baseline and upon causing local venous congestion by inflating a second cuff to 40 mmHg for 4 min (VAR) and during placement of the forearm 40 cm below cardiac level for 4 min (VMR). These measurements were repeated after local infusion of either saline or aminophylline, non-selective adenosine blockers, using the Bier block method.
Rest baseline forearm blood flow was comparable in both arms. Saline did not affect the baseline forearm blood flow. However, aminophylline causes a significant increase in baseline forearm blood flow of 34 ± 6 % (p = 0.002). VAR demonstrated a decrease in forearm blood flow of 49 ± 4.5 % and after saline infusion it remained unchanged, 49 ± 5 % (p = 0.92). However, aminophylline causes significant decrease in the VAR by 35 ± 3 % (p = 0.02). But, both, saline and aminophylline did not affect the VMR.
Arterial vasoconstriction triggered by venous congestion, which is the veno-arterial reflexis seems to be modulated by adenosine, at least partially. This "sensory" reflex requires further pharmacologic physiologic investigation.
局部血管收缩反射、血管肌源性反应（VMR）和静脉-动脉反射（VAR）对于在直立应激期间维持局部血流和全身动脉血压是必需的。其分子机制尚不清楚。我们推测腺苷参与了这些局部反射的激活。
在10名健康男性志愿者（年龄29±3岁，体重指数24±1kg/m²）中对该假设进行了测试。我们使用静脉阻塞体积描记法评估基线时以及通过将第二个袖带充气至40mmHg持续4分钟引起局部静脉充血时（VAR）和在前臂置于心脏水平以下40cm持续4分钟时（VMR）的前臂动脉血流。使用比尔阻滞法在局部输注生理盐水或氨茶碱（非选择性腺苷阻滞剂）后重复这些测量。
双臂的静息基线前臂血流相当。生理盐水不影响基线前臂血流。然而，氨茶碱使基线前臂血流显著增加34±6%（p=0.002）。VAR显示前臂血流减少49±4.5%，输注生理盐水后保持不变，为49±5%（p=0.92）。然而，氨茶碱使VAR显著降低35±3%（p=0.02）。但是，生理盐水和氨茶碱均不影响VMR。
静脉充血引发的动脉血管收缩，即静脉-动脉反射，似乎至少部分受腺苷调节。这种“感觉”反射需要进一步的药理生理学研究。
