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Assessment of alpha-adrenergic receptor subtypes in isolated rat aortic segments

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Summary

  1. 1.

    The postsynaptic α-adrenoceptors in the isolated rat aorta have been characterized according to the sensitivity of the tissue to selective α1- and α2-adrenoceptor agonists and antagonists.

  2. 2.

    The potency (-log EC50) order of the non-selective α-agonist norepinephrine and relatively selective agonists was as follows: norepinephrine (α12; 7.30); clonidine (α21; 7.01); phenylephrine (α12; 6.99), SK & F 89748-A (α12; 6.65); BHT-920 (α2≫α1; 5.56) and M-7 (α21; 4.66).

  3. 3.

    The isolated rat oarta was 12–200-fold more sensitive to the α1-adrenoceptor agonists phenylephrine and SK & F 89748-A, than to the α2-agonists, BHT-920 and M-7.

  4. 4.

    Prazosin is 245–1259-fold more potent than rauwolscine as an antagonist of contractions induced by various α1- and α2-agonists in the rat aorta.

  5. 5.

    These data indicate that constriction of the smooth muscle of the rat aorta to α-adrenergic agonists is mediated through α1- but not α2-adrenoceptors.

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Macia, R.A., Matthews, W.D., Lafferty, J. et al. Assessment of alpha-adrenergic receptor subtypes in isolated rat aortic segments. Naunyn-Schmiedeberg's Arch. Pharmacol. 325, 306–309 (1984). https://doi.org/10.1007/BF00504373

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  • DOI: https://doi.org/10.1007/BF00504373

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