5-Hydroxytryptamine mediated vasocontraction and Ca2+/Calmodulin and Src-kinase dependent Epidermal Growth Factor Receptor Transactivation in Rat aorta (1065.7)

5-Hydroxytryptamine (5-HT) receptors induce vasocontraction and play significant roles in vascular systems. We have previously shown that transactivation of EGFR contributes to α1-adrenergic receptor mediated vasocontraction. Here, we examined EGFR transactivation in 5-HT induced vascular contraction and extracellular-regulated kinase (ERK1/2) activation. Aortic contraction and intracellular [Ca2+] response to 5-HT in aorta and A7R5 cells, respectively, were obtained in the absence and presence of EGFR inhibitor (AG1478). To characterize EGFR transactivation, 5-HT stimulated-EGFR phosphorylation was determined in the absence and presence of AG1478, Ca2+/Calmodulin inhibitor (W7), Src kinase inhibitor (PP2). AG1478 attenuated 5-HT induced vasocontraction and intracellular [Ca2+] response. 5-HT mediated EGFR-transactivation was inhibited by AG1478, W7 and PP2. 5-HT also led to phosphorylation of myosin light chain kinase (MLCK) and ERK1/2 which were partially inhibited by AG1478, but completely by W7 and PP...