[3H]zacopride: ligand for the identification of 5-HT3 recognition sites.
[3H]Zacopride displayed saturable binding to homogenates of the rat entorhinal cortex as measured by the inclusion of the 5-HT3 receptor antagonist BRL43694 in the incubation media. Scatchard analysis indicated a single high affinity binding site (KD 0.76 +/- 0.08 nM, Bmax 77.5 +/- 6.5 fmol (mg protein)-1) with a Hill slope close to unity. Other 5-HT3 receptor antagonists (zacopride, ICS 205-930, GR38032F, GR65630, metoclopramide and cocaine) also competed for the binding site displacing 60% of the total [3H]zacopride binding. 5-HT and 2-methyl-5-HT also were competitive antagonists for [3H]zacopride binding whereas 5-HT1/5-HT2 agonists and antagonists, and agents acting on other neurotransmitter receptors had Ki values greater than 10(-5) M. It is concluded that [3H]zacopride may prove a useful ligand for the study of 5-HT3 recognition sites.
Barnes
N M
NM
Postgraduate School of Studies in Pharmacology, University of Bradford, UK.
Costall
B
B
Naylor
R J
RJ
D000818:Animals; D001549:Benzamides; D001667:Binding, Competitive; D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D001952:Bridged-Ring Compounds; D002540:Cerebral Cortex / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D011985:Receptors, Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000378:metabolism
D001549:Benzamides; D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D001952:Bridged-Ring Compounds; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; C055971:zacopride