RESUMO
After depletion of intracellular Ca2+ stores the capacitative response triggers an extracellular Ca2+ influx through store-operated channels (SOCs) which refills these stores. Our objective was to explore if human umbilical artery smooth muscle presented this response and if it was involved in the mechanism of serotonin- and histamine-induced contractions. Intracellular Ca2+ depletion by a Ca2+-free extracellular solution followed by Ca2+ readdition produced a contraction in artery rings which was inhibited by the blocker of Orai and TRPC channels 2-aminoethoxydiphenyl borate (2-APB), suggesting a capacitative response. In presence of 2-APB the magnitude of a second paired contraction by serotonin or histamine was significantly less than a first one, likely because 2-APB inhibited store refilling by capacitative Ca2+ entry. 2-APB inhibition of sarcoplasmic reticulum Ca2+ release was excluded because this blocker did not affect serotonin force development in a Ca2+-free solution. The PCR technique showed the presence of mRNAs for STIM proteins (1 and 2), for Orai proteins (1, 2 and 3) and for TRPC channels (subtypes 1, 3, 4 and 6) in the smooth muscle of the human umbilical artery. Hence, this artery presents a capacitative contractile response triggered by stimulation with physiological vasoconstrictors and expresses mRNAs for proteins and channels previously identified as SOCs.
Assuntos
Humanos , Compostos de Boro/farmacologia , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Músculo Liso/metabolismo , RNA Mensageiro/genética , Artérias Umbilicais/efeitos dos fármacos , Capacitância Vascular/efeitos dos fármacos , Western Blotting , Células Cultivadas , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/química , Canais de Cálcio/genética , Canais de Cálcio/metabolismo , Cálcio/metabolismo , Agonistas dos Receptores Histamínicos/farmacologia , Histamina/farmacologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Músculo Liso/citologia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/metabolismo , Agonistas do Receptor de Serotonina/farmacologia , Serotonina/farmacologia , Canais de Cátion TRPC/genética , Canais de Cátion TRPC/metabolismo , Artérias Umbilicais/citologia , Artérias Umbilicais/metabolismoRESUMO
El fumar tabaco durante el embarazo aumenta los riesgos en la salud materno-infanto juvenil provocando múltiples alteraciones atribuidas a la nicotina y al monóxido de carbono producidos por el cigarrillo.