Tyrosine kinase participates in alpha 1A-adrenoceptor-mediated increase of intracellular calcium in human embryo kidney 293 cells.
OBJECTIVE
To determine the role of protein-tyrosine kinase (PTK) in alpha 1A-adrenoceptor-mediated increase of [Ca2+]i (intracellular calcium) in human embryo kidney (HEK) 293 cells expressed alpha 1A-adrenoceptor.


METHODS
Effects of two PTK inhibitors: genistein and tyrphostin, were investigated on the increase of [Ca2+]i by using Fura-2, The activity of PTK was measured and the accumulation of [3H] InsPs were observed.


RESULTS
Norepinephrine stimulated a rapid increase in [Ca2+]i to (371 +/- 31) nmol.L-1 in HEK 293 cells. Norepinephrine-induced increase of [Ca2+]i was inhibited by the tyrosine kinase inhibitors quercetin and tyrphostin by 23.8% and 21.4%, respectively, but the accumulation of [3H]InsPs induced by norepinephrine was not. The activity of the plasma-associated tyrosine kinase was increased to (1.73 +/- 0.72)-fold over the control by norepinephrine 10 mumol.L-1. The norepinephrine-activated PTK was inhibited by calphostin C and depletion of intra- and extra-cellular Ca2+.


CONCLUSIONS
The PTK participates in mobilization of Ca2+ mediated by alpha 1A-adrenoceptors in HEK 293 cell lines.
Institute of Vascular Medicine, Third Hospital, Beijing Medical University, Beijing 100083, China.
W Z
WZ
Zhu
B B
BB
Gao
H W
HW
Li
Y Y
YY
Zhang
Q D
QD
Han
D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004622:Embryo, Mammalian; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D020032:Tyrphostins / Q000494:pharmacology
C547713:ADRA1A protein, human; D009281:Naphthalenes; D018340:Receptors, Adrenergic, alpha-1; D020032:Tyrphostins; D019833:Genistein; D011505:Protein-Tyrosine Kinases; C058819:calphostin C; D002118:Calcium; D009638:Norepinephrine; D010646:Phentolamine