The effects of thapsigargin on [Ca2+]i in isolated rat mesenteric artery vascular smooth muscle cells.
The effects of thapsigargin were studied on single cells isolated from side branches of the rat mesenteric artery. Thapsigargin (150 nM) produced a transient increase of [Ca2+]i. This transient rise of [Ca2+]i was unaffected by removing external Ca2+ ions. This suggests that thapsigargin is releasing Ca2+ ions from an intracellular store. In the absence of thapsigargin both noradrenaline and caffeine also produced a transient increase of [Ca2+]i. These increases were abolished by prior exposure to thapsigargin. Correspondingly, the effects of thapsigargin were abolished by prior exposure to caffeine. These results show that thapsigargin releases Ca2+ from the noradrenaline and caffeine-sensitive stores.
Baró
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Department of Veterinary Preclinical Sciences, University of Liverpool, UK.
Eisner
D A
DA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D008638:Mesenteric Arteries / Q000166:cytology / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D009994:Osmolar Concentration; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D013729:Terpenes / Q000494:pharmacology*; D019284:Thapsigargin
D010936:Plant Extracts; D013729:Terpenes; D019284:Thapsigargin; D002118:Calcium; D009638:Norepinephrine