Bradykinin-evoked release of [3H]noradrenaline from the human neuroblastoma SH-SY5Y.
Bradykinin (BK) evoked [3H]noradrenaline ([3H]NA) release from the human neuroblastoma SH-SY5Y and this was enhanced by pre-treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) for 8 min. This effect of BK was inhibited by 500 microM [D-Phe7]BK and 100 microM [Thi5,8,D-Phe7]BK but not by 500 microM [Des-Arg9,Leu8]BK. The BK (B1)-agonist [Des-Arg9]BK did not evoke [3H]NA release. This suggested that SH-SY5Y expressed BK (B2)-receptors coupled to the release of [3H]NA. BK acting at B2-receptors, also elevated intracellular calcium and depolarized SH-SY5Y cells. Although pre-treatment of SH-SY5Y cells with TPA enhanced BK-evoked [3H]NA release, the elevation of intracellular calcium [Ca2+]; was decreased by about 50%. BK-evoked release of [3H]NA in cells not pre-treated with phorbol ester was only 23% dependent on extracellular calcium. In comparison, following phorbol ester treatment approximately 40% of [3H]NA release was dependent on extracellular calcium. Nifedipine (5 microM), CoCl2 (1 mM) and NiCl2 (1 mM) inhibited NA release in SH-SY5Y cells pre-treated with TPA by 16.0, 47 and 44%, respectively. The results of this study showed that BK, acting at B2-receptors, activated [3H]NA release in SH-SY5Y. Part of this effect appeared to be due to activation of L-type calcium channels but the majority of BK-evoked [3H]NA release in SH-SY5Y cells appeared to depend on [Ca2+]i.
McDonald
R L
RL
Department of Cardiovascular Studies, University of Leeds, U.K.
Kaye
D F
DF
Reeve
H L
HL
Ball
S G
SG
Peers
C
C
Vaughan
P F
PF
D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D003035:Cobalt / Q000494:pharmacology; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D009447:Neuroblastoma / Q000378:metabolism*; D009532:Nickel / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D018002:Receptors, Bradykinin / Q000187:drug effects / Q000378:metabolism; D014316:Tritium; D014407:Tumor Cells, Cultured
D018002:Receptors, Bradykinin; D014316:Tritium; D003035:Cobalt; D009532:Nickel; D009543:Nifedipine; D001920:Bradykinin; D002118:Calcium; D009638:Norepinephrine