Vasorelaxant properties of brefeldin A in rat aorta.
The effects of brefeldin A, a putative specific agent that disassembles the Golgi apparatus were assessed on the contractility of de-endothelised rat aorta. Brefeldin A inhibited, either as pre- or as post-treatment, the contractions elicited by K+ (75 mM) or phenylephrine (10 microM), being significantly more potent upon the latter. The thapsigargin (1 microM)-induced rat aorta contraction was less sensitive to brefeldin A inhibition. Pre-treatment with brefeldin A (30-100 microM) did not affect phenylephrine-induced transient contractions in Ca2+-free medium, but strongly inhibited the phenylephrine-induced sustained contractions upon re-admission of Ca2+ to the medium. Brefeldin A was unable to prevent Ca2+ stores refilling. We concluded that brefeldin A inhibits Ca2+ entry but not the pathways activated after Ca2+ stores depletion or the pathways responsible for replenishment of these stores in rat aorta, presumably by disassembling the Golgi apparatus network.
Filipeanu
C M
CM
Department of Physiology, University of Medicine & Pharmacy Gr. T. Popa, Iasi, Romania.
Brailoiu
E
E
Costuleanu
M
M
Costuleanu
A
A
Toma
C P
CP
Branisteanu
D D
DD
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001011:Aorta; D020126:Brefeldin A; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects; D003517:Cyclopentanes / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D018942:Macrolides; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009200:Myocardial Contraction / Q000187:drug effects; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D000316:Adrenergic alpha-Agonists; D000900:Anti-Bacterial Agents; D015220:Calcium Channels; D003517:Cyclopentanes; D018942:Macrolides; D010656:Phenylephrine; D020126:Brefeldin A; D002118:Calcium