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cAMP and cGMP metabolic levels in cerebral tissues were observed in experimental cerebral ischemia induced by clipping cerebral arteries in dogs. Tissue cyclic AMP content markedly increased within 6 h following occlusion of the arteries, however, it gradually decreased with longer period of ischemia. Tissue cyclic GMP concentration in ischemic cerebral tissues displayed a significant decrease. These results illustrated that disorders ensued in cerebral tissue metabolism and transmission of mediators... cAMP and cGMP metabolic levels in cerebral tissues were observed in experimental cerebral ischemia induced by clipping cerebral arteries in dogs. Tissue cyclic AMP content markedly increased within 6 h following occlusion of the arteries, however, it gradually decreased with longer period of ischemia. Tissue cyclic GMP concentration in ischemic cerebral tissues displayed a significant decrease. These results illustrated that disorders ensued in cerebral tissue metabolism and transmission of mediators following ischemic strokes. 对犬脑颅底动脉结扎后引起实验性脑缺血不同时间的皮质环核苷酸(cAMP、cGMP)进行了观察。结果表明,cAMP在缺血早期(6h内)增高,而后逐渐下降。cGMP呈持续降低水平。脑缺血后环核苷酸(cAMP.CGMP)出现的这种变化反映出脑组织细胞代谢、介质传递紊乱状态。 Objective To study the effect of nitric oxide (NO) in the forebrain on the pain behavior of the rat.Methods The tail flick latency (TFL) in lightly pentobarbital anesthetized rat by nociceptive stimulation with radiant heat was measured as the pain threshold.Effects of administration of sodium nitroprusside (SNP) and methylene blue respectively into intracerebroventricle (i.c.v) or septal nucleus on the pain behavior were investigated.Results Compared with control group,administration of SNP into i.c.v significantly... Objective To study the effect of nitric oxide (NO) in the forebrain on the pain behavior of the rat.Methods The tail flick latency (TFL) in lightly pentobarbital anesthetized rat by nociceptive stimulation with radiant heat was measured as the pain threshold.Effects of administration of sodium nitroprusside (SNP) and methylene blue respectively into intracerebroventricle (i.c.v) or septal nucleus on the pain behavior were investigated.Results Compared with control group,administration of SNP into i.c.v significantly produced a facilitation of the TFL(P<0 05),the maximal facilitation of the TFL was 36.2% and time of the facilitation about 20min.This effect of SNP was completely blocked by together with administration of the NO chelater hemoglobin.Administration of SNP into the septal nucleus caused the same effect on the TFL as above.Methylene blue,a soluble guanylate cyclase inhibitor,significantly produced antinociception by i.c.v administration (P<0 05). Conclusions These results suggest that NO in the forebrain produces a facilitation of the pain behavior of the rat and this facilitation is,at least,partially mediated via the NO-cyclic GMP pathway. 目的考察一氧化氮(NO)在前脑对大鼠痛行为的影响。方法采用辐射热作为伤害性刺激,以浅麻状态大鼠甩尾潜伏期(TFL)为测痛指标,观察侧脑室和隔核分别微量注射硝普钠或亚甲基兰对痛阈的影响。结果侧脑室注射硝普钠使大鼠TFL显著性减小(P<0.05),其最大值为36.2%,持续时间为20分钟;该作用可被NO的螯合剂血红蛋白阻断。隔核内注入硝普钠对TFL的影响与上述结果相似。侧脑室注射亚甲基兰使大鼠TFL显著性升高(P<0.05)。结论NO在大鼠前脑对痛行为反应具有易化作用;且部分是通过NO—cGMP通路实现的。 Objective To observe L-Arginine related peptide (L-Arg X)'seffect on rat's platelet aggregation, thrombsis and the plasma level of nitric oxide(NO), cyclic GMP(cGMP) and prostacyclin(PGI 2) Methods Twenty-four Sprague Dewley rats were divided into 2 groups randomly One group was given L-Arg X (61 4 mg·kg -1 ·d -1 ) orally and the other was given placebo Blood was taken from abdominal aorta with a plastic catheter 8 days after treatment Platelet aggregation was measured by turbidimetric... Objective To observe L-Arginine related peptide (L-Arg X)'seffect on rat's platelet aggregation, thrombsis and the plasma level of nitric oxide(NO), cyclic GMP(cGMP) and prostacyclin(PGI 2) Methods Twenty-four Sprague Dewley rats were divided into 2 groups randomly One group was given L-Arg X (61 4 mg·kg -1 ·d -1 ) orally and the other was given placebo Blood was taken from abdominal aorta with a plastic catheter 8 days after treatment Platelet aggregation was measured by turbidimetric method Plasma level of cyclic GMP and prostacyclin was evaluated by radioimmunoassay and nitric oxide by spectrophotometric determination Common carotid artery-external jugular vein bypass was made after rats were anesthetized and weight of wet thrombus was measured with highly sensitive electrical scale Results Platelet aggregation activation decreased compared with placebo (10 75%±3 62)% vs 32 8%±6 62%, P<0 05) adenosine diphosphate(ADP)-inducedby; (11 83%±3 98% vs 34 64%±6 54%, P<0 05) arachidonic acid(AA) induced; weight of wet thrombus lessened (4 0±1 0 vs 7 0±1 7 mg, P<0 05); plasma concerntration of nitric oxide and cyclic GMP increased (22 4±6 1 vs 16 3±2 5 (mol/L, P<0 05; 10 3±2 3 vs 7 0±1 0 nm/L, P<0 05); prostacyclin saw increasing trend but showed no significance compared with placebo(4 76±1 4 vs 4 73±1 84 ng/L, P>0 05) Conclusion The L-Arg X peptide shows strong antiplatelet function compared with placebo It can reduce thrombus weight in vivo, inhibit platelet aggregation in vitro and increase plasma concerntration of nitric oxide and cyclic GMP significantly Its antihemostatic and antithrombotic function might be mediated by L-arginine-nitric oxide-cyclic GMP metablism passway Although plasma level of prostacyclin shows no significant changes, its mechanism remains unknown and needs to be further studied L-Arg X peptide might be regarded as a nitric oxide precursor Because of its beneficial cardiovascular protection with simple chemical structure and evident antithrombotic activation, its phamaceutical value to cardiovascular disease is expected to be further explored 目的 观察左旋精氨酸相关肽 (L -ArgX)对大鼠血小板聚集、血栓形成及血浆一氧化氮 (NO)、环磷酸鸟苷 (cGMP)和前列环素 (PGI2 )的影响。方法 2 4只SD雄性大鼠随机分为 2组 ,分别灌服L -ArgX 6 1 4mg/kg·b w及对同体积空白对照液 ,每日 1次 ,共 8d。 8d后观察大鼠血小板聚集 (比浊法 )、血栓形成 (丝线法 )及血浆NO、cGMP、PGI2 浓度的变化 (分光光度法和放免法 )。结果L -ArgX可显著抑制大鼠血小板聚集率及血栓形成 ,使血浆NO、cGMP浓度升高 ,血浆PGI2 浓度有升高趋势 ,但与对照组相比无统计学差异。结论L -ArgX可抑制血小板聚集 ,其作用机制可能由一氧化氮 -环磷酸鸟苷代谢通路(NO -cGMPpathway)所介导 ,此外尚可能有其它作用机制参与。L -ArgX可视为一种NO前体 ,具有抗凝血作用。
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