[3H]zonisamide binding in rat brain.
We previously reported that zonisamide inhibits both [3H]flunitrazepam and [3H]muscimol binding in rat brain. In the present study, [3H]zonisamide was found to bind in a saturable fashion to the crude synaptosomal fraction of whole rat brain. Linear regression analysis of the binding data in the Scatchard plot indicated a Kd of 90 nM, and a maximal binding capacity of 1.40 x 10(3) fmol/mg protein. Displacement studies revealed an inhibitory effect of clonazepam and an enhancement effect of GABA on specific [3H]zonisamide binding. These results suggest that specific [3H]zonisamide binding sites may have a tight correlationship with benzodiazepine receptors in rat brain.
Mimaki
T
T
Department of Pediatrics, Osaka University Medical School, Japan.
Suzuki
Y
Y
Tagawa
T
T
Karasawa
T
T
Yabuuchi
H
H
D000818:Animals; D000927:Anticonvulsants / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D002998:Clonazepam / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007555:Isoxazoles / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*; D000078305:Zonisamide; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D000927:Anticonvulsants; D007555:Isoxazoles; D011963:Receptors, GABA-A; D000078305:Zonisamide; D005680:gamma-Aminobutyric Acid; D002998:Clonazepam