MOBILIZATION OF A COMMON SOURCE OF SMOOTH-MUSCLE CA2+ BY NOREPINEPHRINE AND METHYLXANTHINES
MOBILIZATION OF A COMMON SOURCE OF SMOOTH-MUSCLE CA2+ BY NOREPINEPHRINE AND METHYLXANTHINES
复制标题
DOI：
10.1152/ajpcell.1981.240.5.c239
复制
发表时间：
1981-01-01
影响因子：
--
通讯作者：
LYNCH, CJ
中科院分区：
文献类型：
--
作者：
DETH, RC;LYNCH, CJ
The ability of norepinephrine (NE), caffeine (CAF), theophylline (THEO), dinitrophenol (DNP) and high K to mobilize cellular Ca2+ in rabbit aorta was examined using 45Ca-efflux techniques. After 10 min of Ca2+ deprivation using Ca-free EGTA [ethyleneglycol-bis (.beta.-aminoethyl ether) N,N,N''N''-tetraacetic acid] or Ca-free La3+ buffers, NE, CAF and DNP still caused an increase in 45Ca-efflux rate indicating a cellular source of 45Ca, while high K did not. Contractile behavior after Ca removal paralleled 45Ca-efflux events. CAF (10 mM) inhibited NE contractile responses. This inhibition was associated with the depletion of the NE-releasable Ca2+ store. Previous exposure to CAF during 45Ca efflux reduced subsequent stimulation of efflux by NE and vice versa. NE and CAF stimulation of 45Ca efflux was not additive. THEO caused a stimulation of 45Ca efflux similar to CAF. CAF THEO and 3-isobutyl-1-methylxanthine caused a 2- to 3-fold increase in cAMP levels in association with their stimulation of 45Ca efflux. NE and methylxanthines apparently mobilize a common cellular Ca2+ source that is associated with contraction in the case of NE but relaxation in the case of methylxanthines.
