Concentraciones subumbrales de serotonina (5-HT) o endotelina-1 (ET-1) potencian la curva concentración respuesta a adrenalina en vena umbilical humana (VUH).

ERRASTI, A; BARD, J.; LUCIANI, L.; ROTHLIN, U.; TRAMONTANO J.; ROTHLIN, R.

Tandil, Argentina

Congreso; XXXIV Reunión anual de la Asociación Argentina de Farmacología Experimental.; 2002

XXXIV Reunión anual de la Asociación Argentina de Farmacología Experimental (SAFE)

Objetive: We tested the hypothesis that subthreshold concentrations of 5-HT or ET-1potentiates adrenaline-induced contraction in this tissue. Methods: HUV rings were mounted in isolated organ baths suspended in Krebs solution. After 2 hs equilibration period rings were pretreated with  5-HT (1 nM and 1.7 nM) or ET-1 (0.1 nM) during 10 min. Then, concentration responses curves (CRC) to adrenaline were constructed (0.01 to 100 mM). Data are expressed as mean ± SEM. Results and conclusions: 5-HT 1.7 nM produced a leftward shift of adrenaline CRC (p<0.05) while 5-HT 1nM did not show any potentiating effect. pEC50 values were 6.99 for control, 7.09 and 7.60 for rings pretreated with 5-HT 1.0 and 1.7 nM respectively. ET-1 10nM also shifted adrenaline CRC to the left in a significant manner (p<0.05). pEC50 values were 6.71 for control, and 7.12 for treated rings. Neither 5-HT nor ET-1 modified adrenaline maximum response. In summary, we conclude that subthreshold concentrations of 5-HT or ET-1 potentiate adrenaline vasoconstrictor action in HUV. In addition, acute fetal hypoxemia and fetal distress increase catecholamine levels in umbilical venous blood. Thus, in these pathological conditions, potentiation could be important for constriction affecting fetal blood flow.