Barium can replace calcium in calmodulin-dependent contractions of skinned renal arteries of the rabbit

Kreye, V. A. W.; Hofmann, Franz; Mühleisen, Martin

doi:10.1007/bf00640919

Cited by 25 publications

(10 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One explanation is that Ba2+ itself may accumulate in endothelial cells at levels sufficient to compensate for the low affinity of Ba2+ for calmodulin, since it is not taken up into intracellular stores or readily removed from the cells. This explanation has also been discussed in previous studies concerning the calmodulindependent contraction of smooth muscle (23,24) and Ca"-ATPase in human erythrocytes (25). Another possibility is that Ba2+ may induce the release of Ca 21 from endothelial intracellular Ca 21 stores, as has been proposed for Ba2+-induced contraction in smooth muscle (24,26).…”

supporting

confidence: 67%

Barium and Strontium Can Substitute for Calcium in Stimulating Nitric Oxide Production in the Endothelium of Canine Coronary Arteries

Yamazaki

Ohara

Harada

et al. 1995

Japanese Journal of Pharmacology

View full text Add to dashboard Cite

ABSTRACT-We investigated whether Ba2+ and Sr2+ can substitute for Ca' in stimulating the nitric oxide (NO) production and cause relaxation in vascular smooth muscle. Ba2+ and Sr2+, like Ca2+, relaxed K+ depolarized canine coronary arteries in the presence of diltiazem. The Ba2+-and Sr2+-induced relaxation was endothelium-dependent and was largely inhibited by NG-monomethyl-L-arginine (L-NMMA) and NGnitro-L-arginine (L-NNA), but not by indomethacin. These cations increased cyclic GMP levels in the coronary artery to a similar extent, and the increment was completely abolished by L-NMMA. The relaxation induced by each cation was attenuated in the presence of a combination of propranolol, phentolamine and atropine, and L-NNA markedly inhibited any remaining relaxation. This indicates that these cations produce endothelium-dependent relaxation through NO production as well as the relaxation mediated by neurotrasmitters. The present study suggests that Ba2+ and Sr2+ can substitute for Ca 2+ in the activation of the NO synthase pathway in the endothelium of canine coronary arteries. Keywords:Barium, Strontium, Nitric oxide, Endothelium, Coronary arteryNitric oxide (NO) synthases have been shown to catalyze the conversion of L-arginine to NO radicals and Lcitrulline in the endothelium (1-3). An increase in intracellular Ca2+ is crucial for the activation of NO synthase in endothelial cells in the presence of calmodulin (4, 5). Ba2+ and Sr2+ have been shown to enter into cultured endothelial cells in response to bradykinin (6). However, no functional role of divalent cations in vascular endothelial cells has as yet been established in contrast to the situation in smooth muscle cells. Ca' and Sr2+ have been shown to cause an endothelium-dependent relaxation of canine coronary arteries contracted by prostaglandin (PG) F2a in the absence of Mgt+, but Ba2+ did not cause such a relaxation (7). On the other hand, Ba2+ and Sr2+ have been shown to substitute for Ca 2+ in the contraction of the rat tail artery (8). To our knowledge, no information has been published regarding any relaxant effect of Ba2+ produced through endothelial function.Our previous study has shown that Ca2+ produces an endothelium-dependent relaxation of K+-depolarized canine coronary arteries in the presence of Ca antagonists (9, 10). These antagonists were useful in distinguishing the contractile effect of Ca 21 on vascular smooth muscle from its relaxant effect through endothelial function. This is because Ca antagonists block L-type Ca2+ channels in smooth muscle, but do not affect the influx of Ca 2+ into endothelial cells (11). Under these conditions, an increase in Ca2+ in the endothelium should have induced production of NO from L-arginine and caused relaxation of the coronary arteries via an increase in cGMP levels. The present study aims to determine whether Ba2+ and Sr2+ can substitute for Ca 2+ in producing relaxation through activation of the NO synthase pathway in endothelial cells.In this study, we measured the tension of and cyclic GMP level...

show abstract

supporting

confidence: 67%

Barium and Strontium Can Substitute for Calcium in Stimulating Nitric Oxide Production in the Endothelium of Canine Coronary Arteries

Yamazaki

Ohara

Harada

et al. 1995

Japanese Journal of Pharmacology

View full text Add to dashboard Cite

show abstract

“…Although the ½Ba 2þ used in the sensing experiment was 100 times higher than that of ½Ca 2þ , it was still not sufficient to trigger the association of TnI with CaM. These results are in agreement with previous studies showing that the ½Ba 2þ required for CaM activation is approximately 200-fold higher than that for ½Ca 2þ (29,30). Overall, these electrical measurements suggested that the SiNW-FETcan be applied for the investigation of the detailed mechanisms of protein-protein interactions.…”

Section: Supporting Information)supporting

confidence: 88%

Label-free detection of protein-protein interactions using a calmodulin-modified nanowire transistor

Lin

Hsieh

Lin

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

122

View full text Add to dashboard Cite

In this study, we describe a highly sensitive and reusable silicon nanowire field-effect transistor for the detection of protein-protein interactions. This reusable device was made possible by the reversible association of glutathione S-transferase-tagged calmodulin with a glutathione modified transistor. The calmodulin-modified transistor exhibited selective electrical responses to Ca 2þ (≥1 μM) and purified cardiac troponin I (∼7 nM); the change in conductivity displayed a linear dependence on the concentration of troponin I in a range from 10 nM to 1 μM. These results are consistent with the previously reported concentration range in which the dissociation constant for the troponin I-calmodulin complex was determined. The minimum concentration of Ca 2þ required to activate calmodulin was determined to be 1 μM. We have also successfully demonstrated that the N-type Ca 2þ channels, expressed by cultured 293T cells, can be recognized specifically by the calmodulin-modified nanowire transistor. This sensitive nanowire transistor can serve as a high-throughput biosensor and can also substitute for immunoprecipitation methods used in the identification of interacting proteins.calcium ion | glutathione S-transfrease | N-type calcium channel | silicon nanowire field-effect transistor

show abstract

“…While Pb has been shown to activate CaM effectively and in fact has a higher affinity than Ca (Fullmer et al, 1985;Richardt et al, 1986;Ouyang & Vogel, 1998), Ba activation requires an around 200-fold higher concentration than Ca for CaM activation (Kreye et al, 1986;Yamazaki et al, 1996). These observations can be explained at least in part by the variations in the ionic radii of these ions and by the differences in metal-ion coordination distances in the EF-hands in the complexes: these would be expected to be reflected in the actual affinity.…”

Section: Discussionmentioning

confidence: 99%

A structural insight into lead neurotoxicity and calmodulin activation by heavy metals

Kursula

Majava

2007

Acta Crystallogr F Struct Biol Cryst Commun

View full text Add to dashboard Cite

Calmodulin is a calcium sensor that is also capable of binding and being activated by other metal ions. Of specific interest in this respect is lead, which is known to be neurotoxic and to have a very high affinity towards calmodulin. Crystal structures of human calmodulin complexed with lead and barium ions have been solved. The results will help in understanding the activation mechanisms of calmodulin by different heavy metals and will provide a detailed view of a putative target for lead neurotoxicity in humans.

show abstract

Barium can replace calcium in calmodulin-dependent contractions of skinned renal arteries of the rabbit

Cited by 25 publications

References 6 publications

Barium and Strontium Can Substitute for Calcium in Stimulating Nitric Oxide Production in the Endothelium of Canine Coronary Arteries

Barium and Strontium Can Substitute for Calcium in Stimulating Nitric Oxide Production in the Endothelium of Canine Coronary Arteries

Label-free detection of protein-protein interactions using a calmodulin-modified nanowire transistor

A structural insight into lead neurotoxicity and calmodulin activation by heavy metals

Contact Info

Product

Resources

About