[Intracellular calcium-dependent contractile effects of serotonin in the human umbilical artery].
BACKGROUND
Absence of innervation is a hallmark of human umbilical vessels. Intervillous space blood flow is regulated by vasoactive substances and calcium dependent contractility, both in normal and pathological conditions such as preeclampsia-eclampsia.


OBJECTIVE
To obtain additional information on the intracellular calcium contractile effects of serotonin in human umbilical arteries.


METHODS
Umbilical arteries from normal pregnancies were dissected, cut in 5 mm rings and mounted in a temperature-controlled isolated organ chamber, using calcium-free Krebs solution. The contractile effects of serotonin, lantane, verapamil and cyclopiazonic acid were evaluated at different concentrations using a computer coupled biopac polygraph.


RESULTS
No differences in response were observed in the presence and absence of intracellular calcium. The positive contractile effects observed with serotonin were significantly decreased with repeated stimulation. An increase in the basal tone of the vessel was observed after calcium supplementation was added to the solution. This effect was minimized in the presence of verapamil and lantane. The contractile effects of serotonin in the calcium-free solution were not affected by the presence of cyclopiazonic acid.


CONCLUSIONS
Serotonin contractile effects in the human umbilical artery depend mainly on intracellular calcium levels which favor the gradual entrance of this ion over time. Calcium influx induced by serotonin is possible through L and Non-L channels apparently insensitive to ciclopiozonic acid.
Briones-Garduño
Jesús Carlos
JC
Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico, D. F. drcarlosbriones@hotmail.com
Castillo-Henkel
Carlos
C
López-Canales
Jorge Skiold
JS
Díaz de León-Ponce
Manuel
M
D000328:Adult; D002118:Calcium / Q000502:physiology*; D005260:Female; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology*; D011247:Pregnancy; D012701:Serotonin / Q000502:physiology*; D014469:Umbilical Arteries / Q000502:physiology*
D012701:Serotonin; D002118:Calcium