[125I]-2-(2,5-dimethoxy-4-iodophenyl)aminoethane ([125I]-2C-I) as a label for the 5-HT2 receptor in rat frontal cortex.
Recent studies of 5-HT2 receptor binding have involved the use of radiolabeled agonists. This report describes the use of [125I]-2-(2,5-dimethoxy-4-iodophenyl)aminoethane ([125I]-2C-I) as a label for low-density 5-HT2 agonist binding sites. A nonhydrolyzable analog of GTP, GppNHp, was found to inhibit the high affinity binding of [125I]-2C-I. 5-HT and several 5-HT2 agonists and antagonists displayed high affinity for this site. In addition, a significant decrease in the Bmax value, but not the KD for [125I]-2C-I was observed at 37 degrees C as compared to that observed at 24 degrees C. Several structure-activity relationships were investigated for displacement of [125I]-2C-I, and the results are consistent with the importance of this receptor in the mechanism of action of hallucinogens. This study demonstrates the utility of [125I]-2C-I as a novel radioligand and provides further data that the 5-HT2 receptor is significantly linked to hallucinogenic activity for several compounds.
Johnson
M P
MP
Department of Medicinal Chemistry and Pharmacognosy, Purdue University, West Lafayette, IN 47907.
Mathis
C A
CA
Shulgin
A T
AT
Hoffman
A J
AJ
Nichols
D E
DE
D000818:Animals; D005625:Frontal Lobe / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007462:Iodobenzenes / Q000138:chemical synthesis; D007553:Isotope Labeling; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000378:metabolism*
D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D011985:Receptors, Serotonin; C063398:2-(2,5-dimethoxy-4-iodophenyl)aminoethane