POSTJUNCTIONAL ALPHA2-ADRENOCEPTORS IN PIAL-ARTERIES OF ANESTHETIZED NEWBORN PIGS
POSTJUNCTIONAL ALPHA2-ADRENOCEPTORS IN PIAL-ARTERIES OF ANESTHETIZED NEWBORN PIGS
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DOI：
10.1159/000457726
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发表时间：
1987-01-01
期刊：
影响因子：
--
通讯作者：
LEFFLER, CW
中科院分区：
文献类型：
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作者：
BUSIJA, DW;LEFFLER, CW
本研究的目的是表征后置α的性质。-adrenoceptors (.alpha。1和。2)麻醉新生猪的脑循环。麻醉仔猪，1-6日龄，使用“封闭”颅窗检查颅底动脉直径。我们检测了在α存在和不存在的情况下交感神经介导的动脉收缩。1-（吡唑嗪）或。α。2-（育亨宾）肾上腺素受体拮抗剂（1mg /kg静脉注射）。初步实验表明，哌唑嗪和育亨宾分别在局部给药苯肾上腺素和可乐定时减轻了枕动脉的收缩。在一组中，电刺激同侧颈上神经节使枕动脉直径从176±±减小。26（平均值+-）SEM)到153 .+-。24 .mu。这种反应不受先前服用哌唑嗪的影响。在第二组中，交感神经刺激使颅底动脉直径从175 .+-减小。23到148 .+-。19 .mu。M，这种反应被事先服用育亨宾所消除。施用育亨宾后，由于局部苯肾上腺素和动脉高血压，动脉仍然收缩。我们得出结论，麻醉新生猪的交感神经刺激通过α 2肾上腺素受体收缩头动脉。
The purpose of this study was to characterize the nature of the postjunctional .alpha.-adrenoceptors (.alpha.1 versus .alpha.2) in the cerebral circulation of anesthetized newborn pigs. Diameters of pial arteries in anesthetized piglets, 1-6 days old, were examined using a ''closed'' cranial window. We examined sympathetically mediated constriction of pial arteries in the presence and absence of .alpha.1-(prazosin) or .alpha.2-(yohimbine) adrenoceptor antagonists (1 mg/kg i.v.). Initial experiments demonstrated that prazosin and yohimbine attenuated constriction of pial arteries during topical administration to the pial surface of phenylephrine and clonidine, respectively. In one group, electrical stimulation of the ipsilateral superior cervical ganglion reduced pial arterial diameter from 176 .+-. 26 (mean .+-. SEM) to 153 .+-. 24 .mu.m, and this response was unaffected by prior administration of prazosin. In a second group, sympathetic nerve stimulation reduced pial arterial diameter from 175 .+-. 23 to 148 .+-. 19 .mu.m, and this response was abolished by prior administration of yohimbine. After administration of yohimbine, pial arteries still constricted in response to topical phenylephrine and arterial hypertension. We conclude that sympathetic nerve stimulation in anesthetized newborn pigs constricts pial arteries via .alpha.2-adrenoceptors.