Zhu Y S, Branch A D, Robertson H D, Huang T H, Franklin S O, Inturrisi C E
Department of Pharmacology, Cornell University Medical College, New York, NY 10021.
Brain Res Mol Brain Res. 1992 Jan;12(1-3):173-80. doi: 10.1016/0169-328x(92)90081-l.
Explantation of rat adrenal medullae to organ culture results in dramatic changes in enkephalins and catecholamines that are similar to the changes seen in vivo in response to denervation, which eliminates transsynaptic impulse activity. We have used rapid and sensitive solution hybridization methods to measure preproenkephalin (PPenk) mRNA and total cellular RNA in samples from rat tissues and adrenal medullary explants. The profiles of adrenal medullary PPenk mRNA, enkephalin-containing (EC) peptides, total cellular RNA and catecholamines [epinephrine (epi) and norepinephrine (norepi)] were measured during 14 days of organ culture. After 8 h in culture, total RNA had declined by 60%, epi and norepi declined 80 to 85% and EC peptides by 50% while the amount of PPenk mRNA per gland increased by 400%. Between 8 h and 14 days total RNA and catecholamine levels remained constant while PPenk mRNA increased to a peak of 85 +/- 10 (S.E.M.) pg/gland at 2-4 days, a value that was 80 times greater than the zero time (preculture) values. EC peptide levels lagged behind the increase in PPenk mRNA and reached a peak of 25 +/- 4 (S.E.M.) pmol Met-enkephalin equivalents/gland at 4 days that was 80 times greater than zero time values. Both PPenk mRNA and EC peptides declined in parallel between 4 and 14 days. The ratio of the copies of proenkephalin (Penk) peptide to PPenk mRNA was estimated to be 25,000 at the time of explantation and after 4 days in culture. From steady-state kinetics half-life estimates of 9.6 h for PPenk mRNA and 14.7 h for Penk peptide were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)
将大鼠肾上腺髓质植入器官培养物中，会导致脑啡肽和儿茶酚胺发生显著变化，这些变化类似于体内去神经支配（消除跨突触冲动活动）时所观察到的变化。我们已使用快速且灵敏的溶液杂交方法来测量大鼠组织和肾上腺髓质外植体样本中的前脑啡肽原（PPenk）mRNA和总细胞RNA。在器官培养的14天内，对肾上腺髓质PPenk mRNA、含脑啡肽（EC）肽、总细胞RNA和儿茶酚胺[肾上腺素（epi）和去甲肾上腺素（norepi）]的情况进行了测量。培养8小时后，总RNA下降了60%，epi和norepi下降了80%至85%，EC肽下降了50%，而每个腺体的PPenk mRNA量增加了400%。在8小时至14天之间，总RNA和儿茶酚胺水平保持恒定，而PPenk mRNA在2至4天增加至峰值85±10（标准误）pg/腺体，该值比零时间（培养前）值高80倍。EC肽水平的增加滞后于PPenk mRNA，在4天达到峰值25±4（标准误）pmol甲硫氨酸脑啡肽当量/腺体，该值比零时间值高80倍。在4至14天之间，PPenk mRNA和EC肽平行下降。在植入时和培养4天后，脑啡肽原（Penk）肽与PPenk mRNA的拷贝数之比估计为25,000。从稳态动力学得出，PPenk mRNA的半衰期估计为9.6小时，Penk肽的半衰期估计为14.7小时。（摘要截短至250字）
