Risperidone inhibits contractions induced by serotonin and histamine and reduces K+ currents in smooth muscle of human umbilical artery.

Risperidone is an antipsychotic commonly used during pregnancy. Because it can cross the placental barrier, our objective was to evaluate its actions on the smooth muscle of the human umbilical artery (HUA). Risperidone preincubation (1-300 nmol/L for 20 minutes) produced a significant decrease in maximum force development induced by serotonin or histamine in HUA rings. When applied on top of stable contractions induced by these agonists risperidone produced quick relaxations (IC(50) = 1 nmol/L for serotonin and 72 nmol/L for histamine). Risperidone induced the contraction of vascular rings depolarized by 40 mmol/L extracellular K(+) but not in the case of 80 mmol/L K(+), suggesting inhibition of K(+) channels. The patch-clamp technique showed that risperidone (3 nmol/L) inhibited whole-cell K(+) currents in freshly isolated HUA smooth muscle cells. Our results are the first showing risperidone effects in human vascular smooth muscle and highlight that its use during pregnancy should be adequately monitored.

Tabaquismo materno: impacto sobre el neonato, placenta y reactividad de la arteria umbilical / Maternal smoking: its impact on the newborn: the placenta and the reactivity of the human umbilical artery

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.

Tabaquismo Materno: Impacto sobre el neonato, placenta y reactividad de la arteria umbilical / Maternal Smoking: Its impact on the newborn. The placenta and the reactivity of the human umbilical artery

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

L, P-/Q- and T-type Ca2+ channels in smooth muscle cells from human umbilical artery.

The electrophysiological and pharmacological properties of Ca(2+) current (I(Ca)) were determined by the whole-cell configuration of the patch-clamp technique in smooth muscle cells from human umbilical artery. Using 5 mM extracellular Ca(2+), depolarizing step pulses from -60 to 50 mV from a holding membrane potential of -80 mV evoked an I(Ca) which activated at membrane potentials more positive than -50 mV and exhibited a maximum current density in a range of 10-20 mV. Steady-state inactivation protocols using a V(test) of 10 mV gave a voltage at one-half inactivation and a slope factor of -35.6 mV and 9.5 mV, respectively. Nifedipine (1 microM), an L-type Ca(2+) channels antagonist, completely inhibited I(Ca), while the L-type Ca(2+) channels agonist Bay-K 8644 (1 microM) significantly increased I(Ca) amplitude. Moreover, the selective blocker of P-/Q-type Ca(2+) channels omega-agatoxin IVA partially blocked I(Ca) (about 40 % inhibition at +20 mV by 20 nM). These pharmacological results suggest that L- and P-/Q-type Ca(2+) channels, both nifedipine-sensitive, underlie the I(Ca) registered using low extracellular Ca(2+). The presence of the P-/Q-type Ca(2+) channels was confirmed by immunoblot analysis. When I(Ca) was recorded in a high concentration (30 mM) of extracellular Ca(2+) or Ba(2+) as current carrier, it was evident the presence of a nifedipine-insensitive component which completely inactivated during the course of the voltage-step (75 ms) at all potentials tested, and was blocked by the T-type Ca(2+) channels blocker mibefradil (10 microM). Summarizing, this work shows for the first time the electrophysiological and pharmacological properties of voltage-activated Ca(2+) currents in human umbilical artery smooth muscle cells.

Effects of light ethanol consumption during pregnancy: increased frequency of minor anomalies in the newborn and altered contractility of umbilical cord artery.

This study explores the effects of light maternal ethanol consumption during pregnancy on the appearance of minor malformations in neonates as well as on the contractile properties of their umbilical cord arteries (UCAs). Clinical external findings of newborns of women declaring light ethanol consumption during any period of their pregnancies [ethanol-exposed group (E group), n=79] were compared with those of nonexposed mothers [nonexposed to ethanol group (NE group), n=100]. Women who smoked or had any associated pathology were excluded. E group mothers consumed, on average, 200-250 mL ethanol/trimester (upper limit 700 mL/trimester). Sixty-six percent of the neonates in the E group presented at least one minor malformation (retromicrognathia and minor anomalies of the auricular/preauricular area were the more common), whereas only 16% of the NE group did (p=0.0000). The percentage of children exhibiting Apgar scores <7 was significantly greater in the E group (11% versus 2%, p=0.0119). UCAs from the E group developed significantly less contractile force (p<0.05) than those of the NE group when exposed to 1 microM serotonin (5-HT) or to a high K+ depolarizing solution. This difference persisted after inhibition of endothelial release of nitric oxide (NO) and prostacyclin. In conclusion, even light drinking should be considered a risk during pregnancy.