Protein kinase C inhibitors decrease endothelin ET(B) receptor mRNA expression and contraction during organ culture...

Area of Science:

• Vascular Biology
• Pharmacology
• Molecular Biology

Background:

• Endothelin ET(B) receptors mediate vasoconstriction.
• Organ culture can alter receptor expression in arterial segments.
• Protein kinase C (PKC) is a key signaling pathway in cells.

Purpose of the Study:

• To investigate the role of PKC in endothelin ET(B) receptor upregulation during organ culture of rat mesenteric arteries.
• To determine the effect of specific PKC inhibitors on receptor-mediated contraction and mRNA expression.

Main Methods:

• Isolated rat mesenteric artery segments were maintained in organ culture for 24 hours.
• Contractile responses to endothelin ET(B) receptor agonist sarafotoxin 6c (S6c) were measured.
• PKC inhibitors (staurosporine, K252a, Ro31-7549) were applied during preincubation or 24-hour treatment.
• Endothelin ET(B) receptor mRNA expression was analyzed using real-time PCR.

Main Results:

• Organ culture significantly increased S6c-induced contraction, indicating ET(B) receptor upregulation.
• PKC inhibitors staurosporine and K252a reduced this enhanced contraction.
• The PKC inhibitor Ro31-7549 abolished the upregulation after 24-hour treatment.
• PKC inhibition also abolished the increased mRNA expression of endothelin ET(B) receptors.

Conclusions:

• PKC signaling is involved in the upregulation of endothelin ET(B) receptors in rat mesenteric arteries during organ culture.
• PKC inhibitors can prevent the increase in receptor expression and function under these conditions.