Serotonin involvement in aversive conditioning: reversal of the fear retention deficit by long-term p-chloroamphetamine but not p-chlorophenylalanine.
Neuroscience letters – December 23, 1982
Source: PubMed
Summary
5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and other serotonin-releasing drugs significantly impair fear retention, as evidenced by reduced immobility in response to inescapable shocks. In a study involving rats, long-term treatment with p-chloroamphetamine (PCA) completely blocked the fear retention deficit caused by acute PCA and fenfluramine, while partially blocking the effects of 5-MeO-DMT. Additionally, serotonin depletion through specific treatments showed varied effects on different serotonin stores, highlighting the critical role of the ascending serotonin pathway in aversive conditioning.
Abstract
5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a serotonin (5-HT) agonist, fenfluramine and p-chloroamphetamine (PCA), which are 5-HT releasers, produce deficits in fear retention as indicated by a notable lack of the immobility resulting from inescapable shocks. Depletion of central 5-HT neurones after long-term PCA treatment (2 X 10 mg/kg) completely blocked the retention impairment resulting from acute PCA (2.5 mg/kg) and fenfluramine (5 mg/kg), and partially blocked the deficit produced by 5-MeO-DMT (4 mg/kg). 5-HT depletion after p-chlorophenylalanine (PCPA) treatment (200, 100, 100 mg/kg, 72, 48 and 24 h before) did not do so; this is in agreement with other findings which suggest the involvement of different 5-HT stores in the action of PCA and PCPA. These data further underline the importance of the ascending 5-HT pathway in aversive conditioning in the rat.