Identification and characterization of functional angiotensin II receptors in human neuroblastoma cells.
The presence of specific AII receptors in 6 different human neuroblastoma cell lines was investigated using binding, cAMP and [Ca2+]i studies. We found high affinity (0.1 nM), low capacity ((1-2).10(3) sites/cell) binding sites for [125I](Sar-1,Ile-8)AII in one half of the cell lines studied. In the positive cell lines mathematical modeling of multiple competition curves among AII and analogs strongly indicated the presence of a homogenous class of sites, i.e., AT1 receptors. The presence of AT1 receptors was further substantiated by AII-induced inhibition of VIP-stimulated cAMP levels and by AII-evoked [Ca2+]i transient. The density of AT1 receptors in neuroblastoma cells was not affected by treatment with pertussis toxin and retinoic acid but was significantly increased by subacute treatment with VIP. In neuroblastoma cells, AII does not stimulate DNA synthesis, suggesting other roles rather than mitogenesis. Neuroblastoma cells represents an interesting model to investigate the function of AII in neural crest derived tissues.
Maggi
M
M
Department of Clinical Physiopathology, University of Florence, Italy.
Finetti
G
G
Cioni
A
A
Mancina
R
R
Baldi
E
E
Serio
M
M
Catalioto
R M
RM
Renzetti
A R
AR
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000378:metabolism; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000805:Angiotensin III / Q000378:metabolism; D057911:Angiotensin Receptor Antagonists; D001667:Binding, Competitive; D001713:Biphenyl Compounds / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007093:Imidazoles / Q000378:metabolism; D007700:Kinetics; D019808:Losartan; D009447:Neuroblastoma / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism; D011725:Pyridines / Q000378:metabolism; D011945:Receptors, Angiotensin / Q000378:metabolism*; D013777:Tetrazoles / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D001713:Biphenyl Compounds; D007093:Imidazoles; D009842:Oligopeptides; D011725:Pyridines; D011945:Receptors, Angiotensin; D013777:Tetrazoles; D000804:Angiotensin II; C066253:PD 123177; D000805:Angiotensin III; C060894:CGP 42112A; C012877:angiotensin II, des-Asp(1)-des-Arg(2)-Ile(5)-; D014660:Vasoactive Intestinal Peptide; D015059:1-Sarcosine-8-Isoleucine Angiotensin II; D000242:Cyclic AMP; D019808:Losartan; D002118:Calcium