subtypes of α1-adrenoceptors in rabbit saphenous vein
نویسندگان
چکیده
we investigated the a,-adrenoceptor subtypes of rabbit saphenous vein which has a mixed functional population of α1 and α2 -adrenoceptors. lateral saphenous veins were obtained from male rabbits weighing 3.20-4 kg, which were killed by overdose with pentobarbitone sodium (i.v. injection). they were easily dissected out and placed in cold, oxygenated modified krebs-henselite solution (krebs). each preparation was cut transversely into 3-4 mm rings and suspended between thick wire supports. the vein rings were mounted in 10 ml isolated organ bath, bathed in krebs maintained at 37°c and gassed with 95% 02 plus 5% co2, cumulative concentration-response curves (ccrc) were constructed by increasing the concentration of the agonists in half-log increments. the preparations were left for a further period of 45-60 min before re-exposure to the agonist. competitive antagonists like prazosin and rauwolscine were incubated in preparations at least for 45 minutes prior to the onset of a second ccrc. the strategy was based on using the a1-adrenoceptor selective agonist, phenylephrine (pe). prazosin, an α1 -adrenoceptor selective antagonist, competitively inhibited contractile responses to phenylephrine with a pa2 value of 8, wb-41 0 1 had a pa2 of 8.6 but a low schild plot slope, while low potency was found with 5mu (pa2 7.2) and hv -723 (pa2 7.97). this data is not consistent with a definitive for αla or αln and taken alone the evidence from prazosin is in favour of αil' however the selective α2- adrenoceptor antagonist delequamine inhibited phenylephrine-induced contractions. overall the data is consistent with phenylephrine-induced contractions being mediated by a,- and a2 -adrenoceptors. the best estimate of the subtype of ajadrenoceptor mediating contraction is ail due to the relatively low absolute pa2 values for prazosin.
منابع مشابه
SUBTYPES OF α1-ADRENOCEPTORS IN RABBIT SAPHENOUS VEIN
We investigated the a,-adrenoceptor subtypes of rabbit saphenous vein which has a mixed functional population of α1 and α2 -adrenoceptors. Lateral saphenous veins were obtained from male rabbits weighing 3.20-4 kg, which were killed by overdose with pentobarbitone sodium (i.v. injection). They were easily dissected out and placed in cold, oxygenated modified Krebs-Henselite solution (Krebs)...
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عنوان ژورنال:
medical journal of islamic republic of iranجلد ۱۴، شماره ۴، صفحات ۳۶۳-۳۶۷
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