The effect of platelet‐derived growth factor (PDGF‐AB) on tone and intracellular Ca2+ ([Ca2+]i) was examined in rabbit isolated ear arteries. Arteries were mounted in a myograph and loaded with the Ca2+‐sensitive fluorescent indicator, fura‐2, for concurrent measurements of isometric force and [Ca2+]i.
PDGF‐AB contracted rabbit ear artery in a concentration‐dependent manner. PDGF‐AB induced tone was associated with a rise in [Ca2+]i. In the presence of noradrenaline, PDGF‐AB induced a similar rise in [Ca2+]i but contraction in response to PDGF‐AB in the presence of noradrenaline was increased compared with PDGF‐AB alone.
PDGF‐AB‐induced rise in [Ca2+]i and tone were abolished by removal of extracellular Ca2+ (with addition of BAPTA, a Ca2+ chelator), and by preincubation with a dihydropyridine calcium channel blocker, (−)−202 791. Bistyrphostin, a selective inhibitor of tyrosine kinases, also inhibited PDGF‐AB‐induced tone, but had no effect on noradrenaline‐ or potassium‐induced tone.
PDGF‐AB contracts rabbit ear artery by increasing Ca2+ entry through voltage‐operated calcium channels. This effect involves activation of a tyrosine kinase.
The effect of platelet‐derived growth factor (PDGF‐AB) on tone and intracellular Ca2+ ([Ca2+]i) was examined in rabbit isolated ear arteries. Arteries were mounted in a myograph and loaded with the Ca2+‐sensitive fluorescent indicator, fura‐2, for concurrent measurements of isometric force and [Ca2+]i.
PDGF‐AB contracted rabbit ear artery in a concentration‐dependent manner. PDGF‐AB induced tone was associated with a rise in [Ca2+]i. In the presence of noradrenaline, PDGF‐AB induced a similar rise in [Ca2+]i but contraction in response to PDGF‐AB in the presence of noradrenaline was increased compared with PDGF‐AB alone.
PDGF‐AB‐induced rise in [Ca2+]i and tone were abolished by removal of extracellular Ca2+ (with addition of BAPTA, a Ca2+ chelator), and by preincubation with a dihydropyridine calcium channel blocker, (−)−202 791. Bistyrphostin, a selective inhibitor of tyrosine kinases, also inhibited PDGF‐AB‐induced tone, but had no effect on noradrenaline‐ or potassium‐induced tone.
PDGF‐AB contracts rabbit ear artery by increasing Ca2+ entry through voltage‐operated calcium channels. This effect involves activation of a tyrosine kinase.
DOI: 10.1111/j.1476-5381.1995.tb14917.x
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