Contractile function and myoplasmic free Ca2+ (Cam) in coronary and mesenteric arteries of endotoxemic guinea pigs

Joyce J. Jones, Julie A. Rapps, Michael Sturek, Mildred L. Mattox, H. Richard Adams, Janet L. Parker

Research output: Contribution to journalArticle

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Abstract

Endotoxin-induced vascular hyporesponsiveness could potentially involve alterations of vascular smooth muscle (VSM) myoplasmic free calcium (Cam) mobilization mechanisms. Contractile function and Cam (fura-2 microfluorometry) regulation were evaluated in vitro using coronary (COR) and mesenteric (MES) artery preparations (100-250 μm inner diameter) isolated from guinea pigs 16 h after intraperitoneal (i.p.) injection of either saline (control; CON) or Escherichia coli endotoxin lipopolysaccharide (LPS; 4 mg/kg). Concentration-response relationships to K+ (5-100 mM) were significantly enhanced in both COR and MES arteries isolated from LPS-treated animals. In contrast, contractile responses to prostaglandin F (PGF; 1-100 μM) were markedly impaired in COR and MES arteries from LPS-treated animals, while endothelin-1 (ET; 1-100 nM)-mediated contractile responses of these arteries were enhanced at the maximal dose (100 nM). In COR arteries, PGF (1-100 μM) and ET (1-100 nM) produced biphasic increases in Cam in both CON and LPS groups. No significant differences were observed in either the initial transient peak or secondary sustained Cam responses between groups, suggesting a lack of effect of LPS upon intracellular Ca2+ release or Ca2+ influx mechanisms in COR arteries. Exposure of MES arteries to PGF and ET produced concentration-dependent increases in Cam in both groups. However, Cam responses of MES arteries lacked initial peak responses, suggesting potential differences in Cam mobilization between COR and MES arteries. Cam responses to K+ (80 mM) and PGF (1-100 μM) were similar in MES arteries from both groups; however, ET-mediated increases in Cam were significantly blunted in LPS compared with CON MES arteries. Thus, endotoxemia produced differential effects upon depolarization (K+) and receptor (PGF, ET)-mediated contractile responses in both COR and MES arteries. Reductions in VSM Cam mobilization appear unlikely as a mechanism for LPS-induced impairment of contractile function of COR and MES arteries; other mechanisms (i.e., decreased Ca2+ sensitivity of contractile proteins) may be involved in effects of LPS upon VSM function of COR and MES arteries.

Original languageEnglish (US)
Pages (from-to)64-71
Number of pages8
JournalShock
Volume11
Issue number1
StatePublished - Jan 1999
Externally publishedYes

Fingerprint

Mesenteric Arteries
Coronary Vessels
Guinea Pigs
Calcium
Dinoprost
Vascular Smooth Muscle
Cytophotometry
Contractile Proteins
Endotoxemia
Fura-2
Endothelin-1
Intraperitoneal Injections
Endotoxins
Blood Vessels
Lipopolysaccharides
Arteries

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine
  • Physiology

Cite this

Jones, J. J., Rapps, J. A., Sturek, M., Mattox, M. L., Adams, H. R., & Parker, J. L. (1999). Contractile function and myoplasmic free Ca2+ (Cam) in coronary and mesenteric arteries of endotoxemic guinea pigs. Shock, 11(1), 64-71.

Contractile function and myoplasmic free Ca2+ (Cam) in coronary and mesenteric arteries of endotoxemic guinea pigs. / Jones, Joyce J.; Rapps, Julie A.; Sturek, Michael; Mattox, Mildred L.; Adams, H. Richard; Parker, Janet L.

In: Shock, Vol. 11, No. 1, 01.1999, p. 64-71.

Research output: Contribution to journalArticle

Jones, JJ, Rapps, JA, Sturek, M, Mattox, ML, Adams, HR & Parker, JL 1999, 'Contractile function and myoplasmic free Ca2+ (Cam) in coronary and mesenteric arteries of endotoxemic guinea pigs', Shock, vol. 11, no. 1, pp. 64-71.
Jones, Joyce J. ; Rapps, Julie A. ; Sturek, Michael ; Mattox, Mildred L. ; Adams, H. Richard ; Parker, Janet L. / Contractile function and myoplasmic free Ca2+ (Cam) in coronary and mesenteric arteries of endotoxemic guinea pigs. In: Shock. 1999 ; Vol. 11, No. 1. pp. 64-71.
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