ISSN:
1420-908X
Keywords:
Iodoproxyfan
;
H3 receptors
;
α 2-Adrenoceptors
;
5-HT3 receptors
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract We determined the affinity and/or potency of the novel H3 receptor antagonist iodoproxyfan atα 2 and 5-HT3 receptors. Iodoproxyfan and rauwolscine (a referenceα 2 ligand) (i) monophasically displaced3H-rauwolscine binding to rat brain cortex membranes (pKi 6.79 and 8.59); (ii) facilitated the electrically evoked tritium overflow from superfused mouse brain cortex slices preincubated with3H-noradrenaline (pEC50 6.46 and 7.91) and (iii) produced rightward shifts of the concentration-response curve (CRC) of (unlabelled) noradrenaline for its inhibitory effect on the evoked overflow (pA2 6.65 and 7.88). In the guinea-pig ileum, iodoproxyfan 6.3µmol/l failed to evoke a contraction by itself but depressed the maximum of the CRC of 5-hydroxytryptamine (pD′2 5.24). Tropisetron (a reference 5-HT3 antagonist) produced rightward shifts of the CRC of 5-hydroxytryptamine (pA2 7.84). In conclusion, the affinity/potency of iodoproxyfan at H3 receptors (range 8.3-9.7 [1]) exceeds that atα 2 receptors by at least 1.5 log units and that at 5-HT3 receptors by at least 3 log units.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02032572
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