Effects of intracerebroventricular injections of 5-HT on systemic vascular resistances of conscious rats.
Effects of intracerebroventricular injections of 5-HT on systemic vascular resistances of conscious rats.
复制标题
5-HT的脑室注射对有意识大鼠全身血管抗性的影响。
DOI：
10.1016/j.mvr.2014.08.002
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发表时间：
2014-09
影响因子：
3.1
通讯作者：
Lewis, Stephen J.
中科院分区：
文献类型：
--
作者：
Davisson, Robin L.;Bates, James N.;Johnson, Alan Kim;Lewis, Stephen J.
关键词：
本研究的目的是确定(i)脑室内注射5-羟色胺（5-HT, 10µg）对有意识大鼠平均动脉血压（MAP）、心率（HR）和肠系膜（MR）、肾脏（RR）和后肢（HQR）血管阻力的影响，（ii）介导这些影响的中枢5-HT受体亚型，以及（iii）一氧化氮（NO）在这些反应表达中的作用。静脉注射5-HT对MAP影响较小，但HR下降（- 18±4%），持续20 min。灌注5-HT后，MR显著升高（+50±7%），HQR显著降低（- 31±3%）。这些反应发生迅速，持续25-35分钟。5-HT也使RR短暂下降（10分钟- 26±8%）。所有这些反应都可以通过先前静脉注射5- ht1 /5- ht2受体拮抗剂甲基塞吉特（10µg）来阻止。静脉注射NO合成抑制剂L-NAME（25µmol/kg）可产生持续的升压反应、心动过缓以及MR、RR和HQR升高。随后静脉注射5-HT产生轻微的升压反应（+7±2%），心动过缓（- 18±3%），MR增加（+52±8%），但RR或HQR未降低。本研究表明，iccv - 5-HT通过激活中枢5- ht1 /5- ht2受体来影响外周血管阻力。L-NAME似乎不干扰5-HT的中枢作用，因为它不能阻止5-HT诱导的心动过缓或肠系膜血管收缩。由于5- ht诱导的RR和HQR下降被L-NAME消除，这些反应可能是由一个活跃的神经源性过程介导的，涉及血管内NO的释放。
The aims of this study were to determine (i) the effects of intracerebroventricular (i.c.v.) injections of 5-hydroxytryptamine (5-HT, 10 µg) on mean arterial blood pressure (MAP), heart rate (HR) and mesenteric (MR), renal (RR) and hindquarter (HQR) vascular resistances of conscious rats, (ii) the central 5-HT receptor subtype which mediates these effects, and (iii) the role of nitric oxide (NO) in the expression of these responses. The i.c.v. injection of 5-HT had minor effects on MAP but produced a decrease in HR (−18 ± 4%), which lasted for 20 min. The i.c.v. injection of 5-HT elicited marked increases in MR (+50 ± 7%) and reductions in HQR (−31 ± 3%). These responses occurred promptly and lasted for 25–35 min. 5-HT also produced a transient decrease in RR (−26 ± 8% at 10 min). All of these responses were prevented by the prior i.c.v. injection of the 5-HT1/5-HT2-receptor antagonist, methysergide (10 µg). The intravenous injection of the NO synthesis inhibitor, L-NAME (25 µmol/kg), produced a sustained pressor response, bradycardia and increases in MR, RR and HQR. Subsequent i.c.v. injection of 5-HT produced a minor pressor response (+7 ± 2%), bradycardia (−18 ± 3%), an increase in MR (+52 ± 8%) but no decreases in RR or HQR. This study demonstrates that i.c.v. 5-HT differentially affects peripheral vascular resistances by activation of central 5-HT1/5-HT2-receptors. It appears that L-NAME did not interfere with the central actions of 5-HT as it did not prevent the 5-HT-induced bradycardia or mesenteric vasoconstriction. Since the 5-HT-induced falls in RR and HQR were abolished by L-NAME, it is possible that these responses are mediated by an active neurogenic process involving the release of NO within the vasculature.
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影响因子：
7.3
作者：
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通讯作者：
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