THE EXISTENCE OF A NEW SUBTYPE OF α‐ADRENOCEPTOR ON THE RAT ANOCOCCYGEUS IS REVEALED BY SGD 101/75 AND PHENOXYBENZAMINE
Open Access
- 1 March 1982
- journal article
- Published by Wiley in British Journal of Pharmacology
- Vol. 75 (3) , 549-552
- https://doi.org/10.1111/j.1476-5381.1982.tb09172.x
Abstract
Noradrenaline and Sgd 101/75 (4(2‐imidazoline‐amino)‐2‐methylindazol‐chlorhydrate) acted as full agonists in contracting the rat anococcygeus. Very low concentrations of phenoxybenzamine (0.3 nm for 2–30 min) reduced preferentially the effects of Sgd 101/75. Preparations made insensitive to Sgd 101/75 by phenoxybenzamine still contracted to noradrenaline, this contraction occurring in the presence of high concentrations (400 μm) of Sgd 101/75. It is concluded therefore that the α1‐adrenoceptor in this preparation is not a homogeneous entity and must be subdivided into at least two subtypes.Keywords
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