Department of Biology, Faculty of Arts and Sciences, Nigde University, Nigde, Turkey.
Clin Exp Hypertens. 2012;34(6):424-8. doi: 10.3109/10641963.2012.665542. Epub 2012 Apr 3.
Reduction in the synthesis or bioavailability of nitric oxide plays a significant role in the development of hypertension. Propolis is a resinous product collected by honeybees from various plant sources. Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the biosynthesis of catecholamines. The aim of this study was to examine the effect of propolis on blood pressure (BP), TH, and total RNA levels in the adrenal medulla, heart, and hypothalamus tissues in chronic nitric oxide synthase (NOS)-inhibited rats by N(w)-nitro-l-arginine methyl ester (L-NAME). Rats received NOS inhibitor (L-NAME) for 15 days to produce hypertension and propolis for the last 5 days. TH activity and total RNA levels significantly increased in adrenal medulla, heart, and hypothalamus tissues in L-NAME-treated groups (P < .05). TH activity and total RNA levels of L-NAME+propolis-treated rats reduced (P < .05) compared with L-NAME-treated groups. TH activity in propolis-treated rats was reduced to the control values. L-NAME led to a significant increase in BP compared with the control group. Propolis administration to L-NAME-treated rats reduced BP but this was not statistically significant compared to L-NAME-treated groups. These results suggest that propolis decreases TH activity in NOS-inhibited hypertensive rats and thereby may modulate the synthesis of catecholamine and BP.
一氧化氮合成或生物利用度的降低在高血压的发展中起着重要作用。蜂胶是由蜜蜂从各种植物源中采集的树脂状产物。酪氨酸羟化酶（TH）是儿茶酚胺生物合成中的限速酶。本研究的目的是通过 N（w）-硝基-L-精氨酸甲酯（L-NAME）检查蜂胶对慢性一氧化氮合酶（NOS）抑制剂大鼠血压（BP）、TH 和肾上腺髓质、心脏和下丘脑组织总 RNA 水平的影响。大鼠接受 NOS 抑制剂（L-NAME）治疗 15 天以产生高血压，并用蜂胶治疗最后 5 天。在 L-NAME 处理组中，TH 活性和总 RNA 水平在肾上腺髓质、心脏和下丘脑组织中显著增加（P <.05）。与 L-NAME 处理组相比，L-NAME+蜂胶处理组的 TH 活性和总 RNA 水平降低（P <.05）。蜂胶处理组的 TH 活性降低到对照值。与对照组相比，L-NAME 导致血压显著升高。给予 L-NAME 处理组的大鼠给予蜂胶可降低血压，但与 L-NAME 处理组相比，这并不具有统计学意义。这些结果表明，蜂胶可降低 NOS 抑制性高血压大鼠的 TH 活性，从而可能调节儿茶酚胺和 BP 的合成。
