An investigation of the 5-HT1D receptor binding affinity of 5-hydroxytryptamine, 5-carboxyamidotryptamine and sumatriptan in the central nervous system of seven species.
The ability of three 5-HT1 receptor agonists, 5-HT (5-hydroxytryptamine), 5-CT (5-carboxyamidotryptamine) and sumatriptan to inhibit the binding of [3H]5-HT, in the presence of cyanopindolol and mesulergine, from cerebral cortical and/or caudate membranes in seven species (dog, guinea-pig, rabbit, pig, human, hamster and calf) has been investigated. Under the experimental conditions used, 5-CT and sumatriptan consistently yielded displacement curves best fit to a two-site model whereas 5-HT always gave a monophasic displacement curve. The pIC50 values obtained with 5-HT displacement gave a mean of 8.1 +/- 0.1 (mean +/- S.E.M.). In contrast the biphasic displacement curves for 5-CT and sumatriptan yielded high and low affinity pIC50 values of 8.3 +/- 0.1, 5.5 +/- 0.1 and 7.6 +/- 0.1, 5.0 +/- 0.1, respectively. These data indicate that under these experimental conditions the high affinity component labelled by [3H]5-HT is the same receptor subtype, previously denoted the 5-HT1D receptor, in all seven species.
Beer
M S
MS
Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, U.K.
Stanton
J A
JA
Bevan
Y
Y
Chauhan
N S
NS
Middlemiss
D N
DN
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D002421:Caudate Nucleus / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D006224:Cricetinae; D004285:Dogs; D006168:Guinea Pigs; D006801:Humans; D007211:Indoles / Q000378:metabolism*; D007700:Kinetics; D011817:Rabbits; D011869:Radioligand Assay; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000031:analogs & derivatives* / Q000378:metabolism*; D013045:Species Specificity; D013449:Sulfonamides / Q000378:metabolism*; D018170:Sumatriptan; D013552:Swine
D007211:Indoles; D011985:Receptors, Serotonin; D013449:Sulfonamides; D012701:Serotonin; D018170:Sumatriptan; C047087:5-carboxamidotryptamine