Ipsapirone depresses neuronal activity in the dorsal raphe nucleus and the hippocampal formation.
Ipsapirone, a putative, novel anxiolytic with a high affinity for 5-HT1A binding sites, suppressed neuronal activity in both the dorsal raphe nucleus and hippocampal formation of urethane-anesthetized rats. In the hippocampus, dentate granule cells matched the responsiveness of dorsal raphe serotonin neurons, the median effective dose for 50% inhibition being 125.0 micrograms/kg in both areas. In contrast, the responses of CA1 pyramidal cells were related directly to baseline firing rates. Slow-firing neurons, for example, were inhibited by 31.3 micrograms/kg and fast-firing cells were unresponsive even up to a dose of 500.0 micrograms/kg. These results indicate a potent effect of ipsapirone on neuronal activity in sites with a high density of 5-HT1A receptors.
D000818:Animals; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects*; D011743:Pyrimidines / Q000494:pharmacology*; D011903:Raphe Nuclei / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains
D011743:Pyrimidines; C043077:ipsapirone