ISSN:
1432-1912
Keywords:
Key words Human right atrium
;
5-HT4 receptor density
;
[125I]-SB 207710
;
β1- and β2-adrenoceptor densities
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract We measured in human atrium the density of 5-HT4 receptors, labelled with [125I]-SB 207710 (1-butyl-4-piperidinyl) methyl 8-amino-7-iodo-1, 4-benzodioxan-5-carboxylate), and compared it with the density of β1- and β2-adrenoceptors, labelled with (–)-[125I]-cyanopindolol. [125I]-SB 207710 (5–1200 pmol/l) labelled a small population of saturable binding sites (B max≈4 fmol/mg protein) with a pKD of 9.7 and with 5-HT4 receptor characteristics, as assessed with competing ligands. The density of atrial binding sites with 5-HT4 receptor characteristics was 10 and 5 times lower, respectively, than the density of β1- and β2-adrenoceptors. We suggest that the small 5-HT4 receptor population may in part explain why the positive inotropic effects of 5-HT are smaller than those of catecholamines mediated through β1- and β2-adrenoceptors.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00169181
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