Koenig H, Goldstone A D, Lu C Y
Department of Neurology, Northwestern University Medical School, Chicago, IL 60611.
Biochem Biophys Res Commun. 1988 Jun 30;153(3):1179-85. doi: 10.1016/s0006-291x(88)81352-4.
The beta-adrenergic agonist 1-isoproterenol (0.1 microM) evokes an acute (less than 5-10 sec) transient increase in the activity of ornithine decarboxylase (ODC), and the levels of polyamines (putrescine, spermidine, spermine) in acutely isolated rat ventricular myocytes. Isoproterenol rapidly (less than 15 sec) increases 45Ca influx and efflux, decreases [Ca2+]i, and stimulates Ca2+-dependent membrane transport (endocytosis, hexose transport, amino acid transport). The beta-adrenergic antagonist propranolol blocks isoproterenol-induced membrane transport. The ODC inhibitor alpha-difluoromethylornithine (DFMO, 5-10 mM) blocks the isoproterenol-evoked increase in ODC activity and polyamine levels and the changes in 45Ca fluxes, [Ca2+]i and membrane transport. Putrescine (0.5-1 mM) replenishes cellular polyamines and reverses the DFMO effect. These data exclude an increase in [Ca2+]i in stimulus-transport coupling, and support the hypothesis that polyamines are messengers in beta-adrenoceptor-mediated regulation of transmembrane Ca2+ fluxes, [Ca2+]i, and Ca2+-dependent membrane transport.
β-肾上腺素能激动剂1-异丙肾上腺素（0.1微摩尔）可引起急性分离的大鼠心室肌细胞中鸟氨酸脱羧酶（ODC）活性以及多胺（腐胺、亚精胺、精胺）水平出现急性（小于5 - 10秒）短暂升高。异丙肾上腺素能迅速（小于15秒）增加45Ca的内流和外流，降低细胞内Ca2+浓度（[Ca2+]i），并刺激Ca2+依赖的膜转运（内吞作用、己糖转运、氨基酸转运）。β-肾上腺素能拮抗剂普萘洛尔可阻断异丙肾上腺素诱导的膜转运。ODC抑制剂α-二氟甲基鸟氨酸（DFMO，5 - 10毫摩尔）可阻断异丙肾上腺素引起的ODC活性和多胺水平升高以及45Ca通量、[Ca2+]i和膜转运的变化。腐胺（0.5 - 1毫摩尔）可补充细胞内的多胺并逆转DFMO的作用。这些数据排除了在刺激-转运偶联过程中[Ca2+]i升高的可能性，并支持了多胺是β-肾上腺素能受体介导的跨膜Ca2+通量、[Ca2+]i和Ca2+依赖的膜转运调节中的信使这一假说。
