Thiomuscimol, a new photoaffinity label for the GABAA receptor.
Thiomuscimol inhibits [3H]muscimol binding to brain GABAA receptors. Exposure of Ag(+)-treated membrane preparations to UV radiation at 254 nm for 40 min in the presence of thiomuscimol (10(-5) M) produced a 20-30% irreversible decrease in high-affinity [3H]muscimol binding sites. The photoaffinity labeling of thiomuscimol was inhibited by GABA (10(-4) M) added prior to exposure to UV light. The data show that thiomuscimol can label the GABAA receptor site and that the ligand can be used as a photoaffinity label for purification and identification of GABA binding sites within the GABAA receptor complex.
Nielsen
M
M
Department of Biochemistry, St. Hans Hospital, Roskilde, Denmark.
Witt
M R
MR
Ebert
B
B
Krogsgaard-Larsen
P
P
D000345:Affinity Labels; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009118:Muscimol / Q000031:analogs & derivatives*; D010777:Photochemistry; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism*; D012834:Silver / Q000494:pharmacology
D000345:Affinity Labels; D011963:Receptors, GABA-A; D009118:Muscimol; D012834:Silver; C020522:thiomuscimol