Human umbilical vein vasoconstriction induced by epinephrine acting on á1B-adrenoceptor subtype .

ANDREA E. ERRASTI , MARIA C. WERNECK DE AVELLAR , FEDERICO M. DARAY, JULIÁN TRAMONTANO, LAURA I. LUCIANI, MARÍA J. LINA BARD , ELIZABETH MARÓSTICA AND RODOLFO PEDRO ROTHLIN

AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY

Elsevier

Lugar: United States ; Año: 2003 vol. 189 p. 1472 - 1480

0002-9378

Human umbilical vein vasoconstriction induced by epinephrine acting on alpha1B-adrenoceptor subtype. Errasti AE, Werneck de Avellar MC, Daray FM, Tramontano J, Luciani LI, Lina Bard MJ, Maróstica E, Rothlin RP. Department of Pharmacology, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 9, 1121 Buenos Aires, Argentina. OBJECTIVE: Our purpose was to determine the presence of alpha(1)-adrenoceptor messenger RNA subtypes and extend the pharmacologic characterization of alpha(1)-adrenoceptors involved in human umbilical vein (HUV) contraction. STUDY DESIGN: Cords (n=124) from healthy patients after term vaginal or cesarean deliveries were used. The vein was carefully dissected out of cords and used for reverse transcription combined with polymerase chain reaction (RT-PCR) to amplify alpha(1)-adrenoceptor transcripts. In isolated organ baths, HUV rings were mounted and cumulative concentration-response curves were constructed either for epinephrine or the selective alpha(1A)-adrenoceptor agonist, A-61603. In other series of experiments, the effects of the selective alpha(1A)- and alpha(1B)-adrenoceptor antagonists (RS-100329 or B8805-033 or spiperone, AH11110A and cyclazosin, respectively) were evaluated to estimate its blocking potencies on epinephrine concentration-response curves. RESULTS: By means of RT-PCR technique alpha(1a)- and alpha(1b)-adrenoceptor transcripts were detected in the HUV. The blocking potency values of RS-100329 or B8805-033 against responses mediated by epinephrine were not consistent with the activation of an alpha(1A)-adrenoceptor population. Moreover, the low potency of the agonist A-61603 was not in accordance with an alpha(1A)-adrenoceptor interaction. On the other hand, the antagonist potencies of spiperone, AH11110A and cyclazosin were in agreement with an interaction on alpha(1B)-adrenoceptor subtype. CONCLUSION: Although alpha(1a)- and alpha(1b)-adrenoceptor messenger RNAs are detected in the HUV, only alpha(1B)-adrenoceptors are involved in epinephrine vasoconstrictor action. Key words: Human umbilical vein, a1-adrenoceptors, epinephrine, vasoconstriction, fetal distress