Repeated peripheral administration of 6R-L-erythro-5,6,7,8-tetrahydrobiopterin alters the binding activities of 5-HT1A and 5-HT2 receptors in rat brain.
Repeated peripheral administration of 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (R-THBP) induced significant changes in the binding activities of serotonergic receptors in the rat brain. The increase in the hippocampus and the decrease in the visual cortex of [3H]8-hydroxy-N,N-dipropyl-2-aminotetralin ([3H]8-OH-DPAT) binding (5-HT1A binding site) were found to be significant following R-THBP administration (20 mg/kg, twice a day for 1 week). [3H]Ketanserin binding (5-HT2 binding site) was increased in the striatum and hippocampus, whereas it was decreased in the cerebellum and visual cortex. Scatchard plot analysis showed ca. 20% reduction in the Bmax of [3H]8-OH-DPAT and [3H]ketanserin binding in the visual cortex, and KD values for [3H]8-OH-DPAT and [3H]ketanserin bindings in the hippocampus were significantly reduced 51% and 66%, respectively. These differential changes in 5-HT binding might be involved in the central action of R-THBP.
Muguruma
K
K
Subfemtomole Biorecognition Project, Research Development Corporation of Japan, Osaka, Japan.
Imamura
K
K
Watanabe
Y
Y
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000378:metabolism; D000818:Animals; D001708:Biopterins / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D007650:Ketanserin / Q000378:metabolism; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000378:metabolism*; D017366:Serotonin Receptor Agonists / Q000378:metabolism; D014316:Tritium
D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; D014316:Tritium; D001708:Biopterins; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D007650:Ketanserin; C003402:sapropterin