Four drugs that bind to the same serotonin receptor subtype (5-HT1A) produce different behavioral effects in rats. 8-OH-DPAT, 5-MeODMT, buspirone, and isapirone all potently inhibit 3H-8-OH-DPAT binding to rat brain membranes (Ki values = 1.9-13 nM). However, only 8-OH-DPAT and 5-MeODMT induce forepaw treading, head-weaving, and tremor, while buspirone and isapirone actually block those behaviors when given alongside the full agonists. All four drugs induce hindlimb abduction, flattened body posture, and Straub tail. The findings suggest that specific components of the serotonin behavioral syndrome are mediated by 5-HT1A receptors.
Psychotic symptoms, especially auditory verbal hallucinations and delusions, are common during both manic and depressive phases of bipolar disorder, though more frequent in mania. Delusions with persecutory, grandiose, and referential themes are most common. Auditory hallucinations often co-occur with delusions, and delusion subtype may vary by mood state and hallucination type. Evidence suggests that how people with bipolar disorder interpret their voices may differ from patterns seen in schizophrenia that predict clinical outcomes. There are significant gaps in understanding the first-person experience of hallucinations in bipolar disorder and their relationship to other symptoms. Further research on cognitive interpretations could inform adapted psychological treatments.