Biochemical and pharmacological characterization of CGS 12066B, a selective serotonin-1B agonist.
CGS 12066B is a novel pyrroloquinoxaline with selectivity for the serotonin-1B (5HT1B) recognition site as assessed by binding, biochemical and electrophysiological studies. The compound had an IC50 value of 51 nM at the 5HT1B recognition site as determined using the binding of [3H]5HT in the presence of 1 microM spiperone. At the 5HT1A receptor the compound had an IC50 value of 876 nM, providing a 5HT1A/5HT1B ratio of 17 in contrast to the putative 5HT1B selective agent trifluoromethylphenylpiperazine (TFMPP) which had a corresponding ratio of 3.6. The compound had minimal affinity for alpha 1-, alpha 2- and beta-adrenoceptors and for dopamine D-1 and D-2 receptors. CGS 12066B, in contrast to TFMPP, which was inactive, was found to inhibit dorsal raphe cell firing with an ED50 value of 358 nmol/kg i.v. The corresponding values for the 5HT1A selective agonists 8-OH-DPAT and ipsapirone were 1.3 and 33 nmol/kg. CGS 12066B was also effective in decreasing rat brain 5-HTP concentrations and inhibiting in vitro 5HT release. The data obtained indicate that CGS 12066B is a reasonably active 5HT1B site agonist, which due to its selectivity as compared to compounds such as TFMPP, will be a useful tool for evaluating the physiological role of such receptors in the mammalian CNS.
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D004082:Dihydroalprenolol; D004594:Electrophysiology; D007031:Hypothalamus / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D011810:Quinoxalines / Q000378:metabolism / Q000494:pharmacology*; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism
D011810:Quinoxalines; D011985:Receptors, Serotonin; C052561:CGS 12066B; D012701:Serotonin; D004082:Dihydroalprenolol; D006916:5-Hydroxytryptophan