Summary
The alpha adrenoceptors present on the saphenous vein of the dog and rabbit were characterised in vitro using the selective alpha1 antagonist prazosin and the alpha2 antagonists rauwolscine and yohimbine. In the dog saphenous vein, prazosin and rauwolscine competitively antagonised contractile responses to phenylephrine and UK-14,304 respectively. Noradrenaline was competitively blocked by prazosin only. In contrast, phenylephrine and methoxamine-induced responses in the rabbit saphenous vein were insensitive to prazosin and corynanthine. Rauwolscine competitively blocked responses to UK-14,304, noradrenaline and phenylephrine and pA2 values were similar against each agonist. Noradrenaline and UK-14,304 were equipotent agonists on the rabbit saphenous vein while in the dog vein noradrenaline has a lower potency than UK-14,304. These results suggest that the dog saphenous vein has a mixed population of alpha adrenoceptors, while the alpha adrenoceptors on the rabbit vein are homogeneous, with characteristics of the alpha2 subtype.
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References
Arunlakshana O, Schild HO (1959) Some quantitative uses of drug antagonists. Br J Pharmacol Chemother 14:48–59
Cambridge D (1981) UK-14,304, a potent and selective alpha2 agonist for the characterisation of alpha adrenoceptor subtypes. Eur J Pharmacol 72:413–415
Constantine JW, Lebel W, Archer R (1982) Functional presynaptic alpha2- but not alpha1-adrenoceptors in dog saphenous vein exposed to phenoxybenzamine. Eur J Pharmacol 85:325–329
De Mey J, Vanhoutte PM (1981) Uneven distribution of post-junctional alpha1- and alpha2-like adrenoceptors in canine arterial and venous smooth muscle. Circ Res 48:875–884
Flavahan NA, McGrath JC (1981) Demonstration of simultaneous alpha1-, alpha2-, beta1- and beta2-adrenoceptor mediated effects of phenylephrine in the cardiovascular system of the pithed rat. Br J Pharmacol 72:585P
Flavahan NA, McGrath JC (1984) Are human vascular alpha-adrenoceptors atypical? J Cardiovasc Pharmacol 6:208–210
McGrath JC (1982) Evidence for more than one type of postjunctional alpha adrenoceptor. Biochem Pharmacol 31:467–484
Purdy RE, Krueger CE, Young S (1980) Evidence for non classical alpha adrenoceptor blockade by prazosin in isolated rabbit blood vessels. Life Sci 27:2187–2195
Shepperson NB, Langer SZ (1981) The effects of the 2-amino tetrahydronaphthaline derivative M7, a selective alpha2 adrenoceptor agonist in vitro. Naunyn-Schmiedeberg's Arch Pharmacol 318:10–13
Shoji T, Tsuni H, Shigei T (1983) A regional difference in the distribution of postsynaptic alpha-adrenoceptor subtypes in canine veins. Naunyn-Schmiedeberg's Arch Pharmacol 324:246–255
Schümann H-J, Lues I (1983) Postjunctional alpha-adrenoceptors in the isolated saphenous vein of the rabbit. Characterisation and influence of angiotensin Naunyn-Schmiedeberg's Arch Pharmacol 323:328–334
Starke K, Docherty JR (1980) Recent developments in alpha-adrenoceptor research. J Cardiovasc Pharmacol 2:S269-S286
Stevens MJ, Moulds RFW (1981) Heterogeneity of post-junctional alpha-adrenoceptors in human vascular smooth muscle. Arch Int Pharmacodyn 254:43–57
Sullivan AT, Drew GM (1980) Pharmacological characterisation of pre- and post-alpha-adrenoceptors in dog saphenous vein. Naunyn-Schmiedeberg's Arch Pharmacol 314:249–258
Timmermans PBMWM, Van Zwieten PA (1981) The post-synaptic alpha2 adrenoceptor. J Auton Pharmacol 1:171–183
Van Rossum JM (1963) Cumulative dose-response curves II. Techniques for the making of dose-response curves in isolated organs and the evaluation of drug parameters. Arch Int Pharmacodyn 143:299–330
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Alabaster, V.A., Keir, R.F. & Peters, C.J. Comparison of activity of alpha-adrenoceptor agonists and antagonists in dog and rabbit saphenous vein. Naunyn-Schmiedeberg's Arch. Pharmacol. 330, 33–36 (1985). https://doi.org/10.1007/BF00586706
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DOI: https://doi.org/10.1007/BF00586706