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In pursuit of the α‐adrenoceptor: a fine‐structural and electron autoradiographic study using 3 H‐phenoxybenzamine and smooth muscle from the cat and guinea‐pig
Author(s) -
GRAHAM J. D. P.,
IVENS CAROLINE,
LEVER J. D.,
McOUISTON R.,
SPRIGGS T. L. B.
Publication year - 1971
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1971.tb08028.x
Subject(s) - phenoxybenzamine , guinea pig , vas deferens , organelle , electron microscope , vesicle , cytoplasm , biology , synaptic vesicle , anatomy , chemistry , biophysics , endocrinology , microbiology and biotechnology , receptor , membrane , biochemistry , physics , optics
Summary1 Electron microscopical evaluation of sets of serial fine sections of pancreatic arteriolar muscle of the cat showed no significant difference between the number of pinocytotic vesicles per unit length of smooth muscle cell membrane in ‘synaptic’ and ‘non‐synaptic’ regions. 2 With high resolution autoradiography, 3 H‐phenoxybenzamine was found to be distributed over the cytoplasm and nuclei of smooth muscle cell profiles of guinea‐pig vas deferens, although no localization in relation to discrete morphological organelles was evident. 3 ‘Specific protection’ of α‐adrenoceptors using 606 μM noradrenaline resulted in a significant diminution in the binding of 3 H‐phenoxybenzamine as evidenced by a decrease in silver grain concentrations over smooth muscle cell profiles in autoradiographs. 4 The significance of these findings in relation to the site and distribution of α‐adrenoceptors is discussed.