PT  - JOURNAL ARTICLE
AU  - GOODMAN, FRANK R.
AU  - WEISS, GEORGE B.
TI  - EFFECTS OF LANTHANUM ON <sup>45</sup>Ca MOVEMENTS AND ON CONTRACTIONS INDUCED BY NOREPINEPHRINE, HISTAMINE AND POTASSIUM IN VASCULAR SMOOTH MUSCLE
DP  - 1971 May 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 415--425
VI  - 177
IP  - 2
4099  - http://jpet.aspetjournals.org/content/177/2/415.short
4100  - http://jpet.aspetjournals.org/content/177/2/415.full
SO  - J Pharmacol Exp Ther1971 May 01; 177
AB  - In rabbit aortic smooth muscle lanthanum ion (La+++) differentially inhibited contractions induced by potassium (K+), norepinephrine (NE) and histamine (inhibition of K+ NE histamine) in a sequence that differed from that reported previously for Ca++ depletion (inhibition of K+ histamine NE) under similar conditions. Addition of 1.5 mM La+++ reduced the 45Ca tissue space and produced a sustained increase in 45Ca efflux from the isolated media-intimal layer of aortic muscles washed out in Tris solution containing no added Ca++. The addition of ethylenediamine tetraacetic acid or 1.5 mM Ca++ under analogous conditions elicited sustained increases in 45Ca efflux. Thus, it appears that La+++ acts at some superficial cellular sites in vascular smooth muscle to prevent reuptake or rebinding of Ca++ at these sites and to inhibit tension responses dependent upon release of Ca++ from these sites. These findings support the idea that the induction and maintenance of contractile responses by stimulatory agents depend upon the utilization of different Ca++ sites or stores in rabbit aortic smooth muscle. © 1971 by The Williams & Wilkins Co.