Transcriptional up-regulation in expression of 5-hydroxytryptamine2A and transcriptional down-regulation of angiotensin II type 1 receptors during organ culture of rat mesenteric artery.
The purpose of this study was to investigate in rat mesenteric artery if there is up-regulation of 5-hydroxytryptamine (5-HT) receptors and angiotensin II receptors and the potential role of protein kinase C activation in the smooth muscle cells during organ culture. Angiotensin II, 5-HT and potassium induced contraction of ring segments without endothelium, monitored by a sensitive in vitro pharmacology method. After the culture of the arterial ring segments for 24 hr, the concentration-contraction curves induced by 5-HT slightly shifted towards to the left with pEC(50) from 6.64+/-0.11 to 6.84+/-0.11 and a significant increase in E(max) from 147+/-11% to 246+/-15% (P<0.05), compared with that obtained in fresh segments. In contrast, the angiotensin II concentration-contraction curve only showed a significant decrease in E(max) from 99+/-10% to 37+/-8%. Specific antagonists for the 5-HT type 2A receptors (5-HT(2A)) and angiotensin II type 1 receptors (AT(1)) demonstrated that the contractions occurred via 5-HT(2A) and AT(1) receptors, respectively. Real-time PCR revealed that the 5-HT(2A) receptor mRNA was up-regulated in parallel with the contractile response while there was a down-regulation of AT(1) receptor mRNA. Transcriptional inhibitor actinomycin D and specific protein kinase C inhibitor Ro31-8220 demonstrated that it was a transcriptional mechanism with involvement of protein kinase C that regulated the enhanced expression of 5-HT(2A) receptors in the mesenteric artery.
Luo
Guogang
G
Division of Experimental Vascular Research, Institute of Medicine, Lund University, SE-221 84 Lund, Sweden.
Xu
Cang-Bao
CB
Cao
Yong-Xiao
YX
Edvinsson
Lars
L
D000804:Angiotensin II; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D007211:Indoles / Q000494:pharmacology; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism*; D009924:Organ Culture Techniques; D016133:Polymerase Chain Reaction; D011188:Potassium; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D044402:Receptor, Serotonin, 5-HT2A / Q000235:genetics / Q000378:metabolism*; D012701:Serotonin; D058826:Serotonin 5-HT2 Receptor Agonists; D014158:Transcription, Genetic / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects
D047228:Angiotensin II Type 1 Receptor Blockers; D004791:Enzyme Inhibitors; D007211:Indoles; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D044402:Receptor, Serotonin, 5-HT2A; D058826:Serotonin 5-HT2 Receptor Agonists; D000804:Angiotensin II; D003609:Dactinomycin; D012701:Serotonin; D003513:Cycloheximide; D011493:Protein Kinase C; D011188:Potassium; C064758:Ro 31-8220