Regulation of Nervous Activity by Endogenous Prostaniods

对神经刺激诱导的输精管收缩的影响：在豚鼠输精管中，腹下神经的节前和节后刺激均诱导由rapig瞬时相位和延迟的强直相位组成的双相收缩。吲哚美辛部分抑制节前刺激引起的收缩，但不抑制节后刺激引起的反应。PGE_2可逆转吲哚美辛的收缩抑制作用，并能延迟时相收缩的开始，增加时相收缩和强直收缩的高度，显著增强ATP和去甲肾上腺素引起的收缩。米帕林和前列腺素E_2受体拮抗剂SC 19220可抑制节前刺激引起的收缩。PGE_2和花生四烯酸可逆转这种抑制作用。提示内源性PGE_2在豚鼠腹神经节的神经传递中起重要作用。 关于我们 豚鼠回肠：吲哚美辛可使烟碱或P物质引起的乙酰胆碱释放量降低到对照的40%左右，而对5-HT或电场刺激（EFS）引起的乙酰胆碱释放量无影响。PGE_2可逆转消炎痛的抑制作用。甲哌克林是一种磷脂酶A_2的抑制剂，它能抑制烟碱和P物质释放乙酰胆碱，其作用程度与消炎痛相当。PGI_2类似物OP-41483对尼古丁释放的抑制作用比PGE_2强。这种作用被A激酶抑制剂H-89所消除。PGD_2、PGF_2<2alpha>、TXA_2类似物治疗无效。PGI_2的释放量是PGE_2的5倍。这些结果表明，内源性PGI_2和PGE_2均能调节肌间神经丛胆碱能神经元的兴奋性，其作用是通过激活胞内cAMP系统而实现的。5-脂氧合酶抑制剂可抑制EFS释放ACh，而12-脂氧合酶抑制剂则不抑制EFS释放ACh。花生四烯酸、5-HETE、LTD_4和LTE_4均能逆转这种抑制作用，而LTB_4和LTC_4则不能逆转这种抑制作用，说明5-脂氧合酶代谢产物对Efs诱导的Ach释放有调节作用。少

Effects on the contraction of vas deferens induced by nerve stimulation : In guinea pig vas deferens, both pre- and post-ganglionic stimulations of hypogastric nerve induced a biphasic contraction consisting of a rapig transient phas and delayed tonic Phase. Indomethacin partly inhibited the contraction induced by pre-ganglionic stimulation, but not the responses by post-ganglionic stimulation. The indomethacin inhibition was reversed by PGE_2- PGE_2 also delayed the onset of phasic contraction and increased the height of both phasic and tonic contractions, and significantly enhanced the contraction induced by authentic ATP and norepinephrine. The contraction induced by pre-ganglionic stimulation was inhibited by mepacrine and PGE_2 receptor antagonist, SC19220. PGE_2 and arachidonic acid reversed these inhibition. The findings suggest that endogenous PGE_2 is important in neurotransmission in the plevic ganglion of guinea pig.Effects on the release of ACh from the myenteric plexus of … More guinea pig ileum : The amount of ACh released in response to nicotine or substance P was depressed to about 40% of control by indomethacin, whereas that induced by 5-HT or electrical field stimulaltion(EFS)was not affected. The inhibitory effect of indomethacin were reversed by PGE_2. Mepacrine, an inhibitor of pbospbolipase A_2, depressed the release of ACh by nicotine and substance P to the same extent as indomethacin. OP-41483, an analogue of PGI_2, recovered inhibited nicotine-induced release more effectively than PGE_2. This effect was abolished by H-89, an A-kinase inhibitor. PGD_2, PGF_<2alpha> and TXA_2 analogue were ineffective. PGI_2 was released during incubation of preparation in the amount as much as 5 times of PGE_2. These results indicate that both endogenous PGI_2 and PGE_2 regulate the excitability of cholinergic neurons in the myenteric plexus and that the effects are mediated by the activation of intracellular cyclic AMP system. The ACh release by EFS was inhibited by 5-lipooxygenase inhibitors but not by 12-lipoxygenase inhibitor. The inhibitory effects were reversed by arachidonic acid, 5-HETE, LTD_4 and LTE_4, but not by LTB_4 and LTC_4, indicating the regulation5-lipoxygenase metavolites on efs induced ach release.In conclusion, many prostanoias contribute for maintaing the activity of the myeyerixc plecus of guinea pig iluem, but the kind of prostanoid concerned may diffe with different stimuli applied to nerve. Less