A transient expression of functional alpha2-adrenergic receptors in white matter of the developing brain.
A transient expression of functional alpha2-adrenergic receptors in white matter of the developing brain.
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发育中大脑白质中功能性α2-肾上腺素受体的短暂表达。
DOI：
10.1002/syn.20174
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Murrin,LCharles
中科院分区：
文献类型：
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作者：
Sanders,JeffD;Happe,HKevin;Murrin,LCharles
去甲肾上腺素是一种神经递质，由α-1、α-2和β-肾上腺素能受体介导，具有外周和中枢作用。本文用放射自显影技术观察了α-2肾上腺素能受体在发育中的白质束中的表达。在大鼠中，这些受体在孕20天时出现在胼胝体和前连合中。对它们在出生后1天的表达进行量化显示，在出生后1天，其表达达到高峰，随着发育成熟而减少，到出生后21天消失。在出生后发育的前十天，前连合的表达持续升高，然后在出生后第21天下降到接近背景水平。通过激动剂刺激的[35S]GTPγS结合进一步鉴定受体，证实α-2肾上腺素能受体在发育早期与G蛋白功能偶联，因此是成熟的受体。原位杂交未检测到任何α-2肾上腺素能受体亚型(A、B和C)在出生后第5天的脑白质束中的表达。[~3H]RX821002乳剂放射自显影显示细胞间和细胞体上的放射自显影颗粒密度相当。综上所述，这些数据表明，α-2肾上腺素能受体在远离脑白质表达的部位合成，并可能指导这些脑连合的成熟。Synapse 57：213-222,2005。©2005 Wiley-Liss Inc.
Norepinephrine is a neurotransmitter with peripheral and central actions mediated by α‐1, α‐2, and β‐adrenergic receptors. In this paper, we report an expression of α‐2 adrenergic receptors in developing white matter tracts as revealed by [3H]RX821002 autoradiography. In rats, these receptors are present in the corpus callosum and anterior commissure at gestational day 20. Quantification of their postnatal expression reveals peak expression in the corpus callosum at postnatal day 1, which decreases with maturation and disappears by postnatal day 21. Expression in the anterior commissure is persistently elevated throughout the first ten days of postnatal development and then decreases to near background levels by postnatal day 21. Further characterization of the receptors by agonist‐stimulated [35S]GTPγS binding verifies α‐2 adrenergic receptors are functionally coupled to G proteins early in development and therefore are mature receptors. In situ hybridization did not detect mRNA for any of the α‐2 adrenergic receptor subtypes (A, B, and C) in white matter tracts of postnatal day 5 brain. [3H]RX821002 emulsion autoradiography demonstrated autoradiographic grains that were of comparable density between cells and over cell bodies. Collectively, these data suggest that α‐2 adrenergic receptors in neonatal commissures are synthesized at sites distant from their white matter expression and may be guiding the maturation of these brain commissures. Synapse 57:213–222, 2005. © 2005 Wiley‐Liss, Inc.