Importance of inositol (1,4,5)-trisphosphate, intracellular Ca2+ release and myofilament Ca2+ sensitization in 5-hydroxytryptamine-evoked contraction of rabbit mesenteric artery.

摘要: Abstract 1. Small strips from third-order branches of rabbit mesenteric artery (approximately 150-200 microM wide) contracted in response to noradrenaline (10 microM) or 5-hydroxytryptamine (5-HT; 10 oxygenated Krebs solution containing 2.5 mM Ca2+. In a Ca(2+)-free mock intracellular (0 Ca2+ plus 0.2 EGTA), and caffeine mM) induced only single, transient contraction strips, while 5-HT failed induce any response. 2. which had been permeabilized with Staphylococcus alpha-toxin bathed solution, microM), D-myo-inositol (1,4,5)-trisphosphate (IP3, 100 but not contraction. contrast the non-permeabilized contractions noradrenaline, IP3 were restored by prior incubation min) 0.08 The muscle required presence guanosine 5'-triphosphate (GTP), although absence GTP alone did 3. Exposure significantly reduced subsequent contractile responses caffeine. Contractile abolished Ca(2+)-ATPase inhibitor, thapsigargin (1 microM). 4. (0.1-10 concentration-dependent strips. submaximally 0.5 Ca2+/100 GTP, addition stimulated further protein kinase C H-7 5-HT/GTP-induced contraction, alter Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)