Mechanisms involved in UTP-induced contraction in isolated rat aorta.
The mechanisms of UTP-induced contractions in the rat aorta strips were studied. These were only partially inhibited in a Ca(2+)-free medium or by incubation with verapamil or nifedipine. Successive challenges did not decrease the magnitude of the contraction in the absence of external Ca(2+). Quin 2(acetoxymethyl) ester (Quin 2AM), 8-(N,N-diethylamino)octyl 3,4,5-trimetoxybenzoate (TMB-8), thapsigargin and ryanodine inhibited these contractions. The participation of protein kinase C is also very likely, since downregulation by the phorbol 12,13 dibutyrate (PDB) decreased UTP-induced contraction, and staurosporine and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) antagonized UTP-induced contractions and relaxed UTP-induced tonic contractions. Therefore, different pools of intracellular Ca(2+) and protein kinase C seem to participate in UTP-induced contraction and in the mechanisms of maintenance in a Ca(2+)-free medium.
López
C
C
Laboratorio de Farmacología, Departamento de Medicina, Facultad de Medicina, c/ Julián Clavería s/n, 33006, Oviedo, Spain.
Sánchez
M
M
Hidalgo
A
A
García de Boto
M J
MJ
D000818:Animals; D002118:Calcium / Q000172:deficiency / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009543:Nifedipine / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014544:Uridine Triphosphate / Q000494:pharmacology* / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D007295:Inositol Phosphates; D014700:Verapamil; D011493:Protein Kinase C; D009543:Nifedipine; D002118:Calcium; D014544:Uridine Triphosphate