Hayashi S, Park M K, Kuehl T J
Life Sci. 1984 Jul 16;35(3):253-60. doi: 10.1016/0024-3205(84)90108-5.
To find whether effects of adrenergic and cholinergic agents on cerebral artery were dependent on maturity, we examined responses of isolated cerebral artery strips harvested from premature, term newborn and adult baboons. Although cerebral arteries from many species are only mildly sensitive to norepinephrine, we found the perinatal cerebral arteries to be quite responsive to the amine. Cerebral arteries from premature and newborn baboons were significantly (P less than 0.001) more sensitive to norepinephrine than were arteries from adults; medium effective concentration (EC50) for norepinephrine were 3 X 10(-8), 6 X 10(-8) and 32 X 10(-8)M for prematures, newborns and adults, respectively. Arteries showed a similar age-dependence in the sensitivity of the response to phenylephrine, an alpha 1-adrenoceptor agonist. EC50 values for KC1 did not differ among groups, nor did the maximum response to norepinephrine. Arteries from premature and newborn baboons showed marked contractile response to acetylcholine (maximum tensions 5.9 +/- 0.6 and 6.4 +/- 0.8 g/mm2, respectively), whereas arteries from adult baboons showed little response (0.6 +/- 0.1 g/mm2). Arteries from premature and newborn animals showed a more marked relaxation response to isoproterenol than did arteries from adult animals; the degree of relaxation from an induced contraction was 63% (premature), 72% (newborn) and 10% (adult). There was no age-dependence in the relaxation response to sodium nitrite. We conclude that the events coupling alpha 1, beta or muscarinic receptor activation with cerebral arterial contraction or relaxation are more effective in perinatal than in adult baboons.
为了探究肾上腺素能和胆碱能药物对脑动脉的作用是否依赖于成熟度，我们检测了从早产、足月新生和成年狒狒分离得到的脑动脉条的反应。尽管许多物种的脑动脉对去甲肾上腺素仅表现出轻度敏感，但我们发现围产期脑动脉对该胺类物质反应相当灵敏。早产和新生狒狒的脑动脉对去甲肾上腺素的敏感性显著高于成年狒狒（P<0.001）；早产、新生和成年狒狒对去甲肾上腺素的半数有效浓度（EC50）分别为3×10⁻⁸、6×10⁻⁸和32×10⁻⁸M。动脉对α1肾上腺素能受体激动剂去氧肾上腺素反应的敏感性也呈现出类似的年龄依赖性。各组对氯化钾的EC50值以及对去甲肾上腺素的最大反应均无差异。早产和新生狒狒的动脉对乙酰胆碱表现出明显的收缩反应（最大张力分别为5.9±0.6和6.4±0.8 g/mm²），而成年狒狒的动脉反应较弱（0.6±0.1 g/mm²）。早产和新生动物的动脉对异丙肾上腺素的舒张反应比成年动物的动脉更明显；由诱导收缩引起的舒张程度分别为63%（早产）、72%（新生）和10%（成年）。对亚硝酸钠的舒张反应不存在年龄依赖性。我们得出结论，在围产期，将α1、β或毒蕈碱受体激活与脑动脉收缩或舒张相偶联的事件比成年狒狒更有效。
