alpha1-adrenoceptor mRNA subtypes present in human umbilical vein (HUV).

ERRASTI, A; AVELLAR, C.; BARD, J.; DARAY, F.; LUCIANI, L.; TRAMONTANO J. AND ROTHLIN, R.

Corrientes, noviembre de 2001.

Congreso; XXXIII Reunión anual de la Asociación Argentina de Farmacología Experimental (SAFE); 2001

Asociación Argentina de Farmacología Experimental (SAFE)

a1-adrenoceptor mRNA subtypes present in human umbilical vein. Errasti AE, Avellar MC, Daray FM, Tramontano J, Luciani LI, Bard J, Marostica E, & Rothlin RP. 3º Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155. Piso 9. 1121. farmaco3@fmed.uba.ar The aim of the present work was to determine the mRNA of a1-adrenoceptor subtypes present in this tissue using reverse transcription combined with polymerase chain reaction (RT-PCR) assay and further pharmacologically characterize the a1-adrenoceptor mediating contraction in human umbilical vein (HUV). RT-PCR assay was performed on total RNA extracted from seven umbilical veins in order to  amplify a1a-  a1b- and a1d- adrenoceptor mRNA subtypes. RT-PCR revealed positive amplification of a1a and a1b subtype genes meanwhile a1d PCR product of the predicted size was not detected at all the HUV samples analysed. HUV rings were mounted in isolated organ baths and cumulative concentration-response curves (CRC) to adrenaline were constructed in presence of a1A  (RS-100329 and B8805-033) and a1B (spiperone, AH11110A and cyclazosin) antagonists. In other HUV rings CRC to the a1A  selective agonist, A-61603 was performed. The affinity values of RS-100329 (pA2=7.90), B8805-033 (pA2=4.9) spiperone (pA2=8.59), AH11110A (pA2=7.80) and cyclazosin (pA2=10.03) against responses mediated by adrenaline were consistent with the activation of an a1B-adrenoceptor population in this tissue. Furthermore, the pCE50 value for A-61603 ( 5.46 ± 0.15) was significantly lower than that for adrenaline (7.01 ± 0.08; p< 0.05) suggesting non-involvement of an a1A-adrenoceptor in this response. In conclusion, these data indicate the presence of a1b-adrenoceptor as well as a1a-adrenoceptor mRNA subtypes but only a1B-adrenoceptors are involved in the HUV vasoconstrictor action of adrenaline.