ISSN:
1432-1912
Keywords:
[3H]Ketanserin
;
5-HT2 receptors
;
[125I]BE 2254
;
α1-Adrenoceptors
;
Human and pig brain cortex
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary 1) The binding characteristics of [3H]ketanserin (a reported selective radioligand for serotonin 5-HT2 receptors) and [125I]BE 2254 (which labels selectively α1-adrenoceptors) were characterized in brain frontal cortex membranes of pig and man. 2) Saturation experiments indicated that both radioligands label apparently a homogeneous class of binding sites in human and pig fontal cortex membranes. 3) Competition experiments with [125I]BE 2254 using 17 agonists and antagonists showed monophasic and steep curves in human and pig frontal cortex membranes. The pharmacological profile of these sites is typical of α1-adrenoceptors. 4) In competition experiments with [3H]ketanserin, most of the tested compounds displayed shallow or biphasic curves. In particular, α1-adrenoceptor-selective antagonists (prazosin, WB 4101, BE 2254...) displaced with nanomolar affinity about 15 and 40% of the specific [3H]ketanserin binding in human and pig frontal cortex membranes, respectively. 5) The minor component of [3H]ketanserin binding correlated highly significantly with [125I]BE 2254 binding in both membrane preparations. 6) The major component of [3H]ketanserin binding to pig and human frontal cortex membranes correlated significantly with [3H]ketanserin binding in rat brain cortex membranes (which is essentially to 5-HT2 receptors). 7) The present data demonstrate that [3H]ketanserin in nanomolar concentrations binds significantly to α1-adrenoceptors in human and pig frontal cortex membranes; this suggests a rather limited degree of selectivity of ketanserin for 5-HT2 receptors in pig and human tissues.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00172788
