Francisco S Guimarães

Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.

2 papers in the library · publishing 2024-2026

Papers

Ayahuasca modulation of traumatic-like fear memories requires infralimbic cortex BDNF-dependent mechanisms in rats.

European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology February 1, 2026 Isabel Werle, Francisco S Guimarães, Rafael G Dos Santos et al.

Ayahuasca, a brew containing the psychedelic DMT, helps rodents overcome persistent and generalized fear memories by boosting brain-derived neurotrophic factor (BDNF) signaling in the infralimbic (IL) region of the medial prefrontal cortex. In rats exposed to stress or high-intensity fear conditioning, repeated ayahuasca (0.3 mg/kg DMT) enhanced extinction learning and its retention, and reduced fear generalization. These effects were blocked by infusing an anti-BDNF antibody or a TrkB receptor antagonist into the IL cortex. The reduction in fear generalization depended on BDNF in females but not males. The findings suggest psychedelics may aid in treating difficult-to-extinguish trauma memories, such as those in PTSD.

DOI: 10.1016/j.euroneuro.2025.11.009 Full text 5-ht2a receptor Microdosing Neuroplasticity Behavioral flexibility +1

Genetic ablation of the isoform γ of PI3K decreases antidepressant efficacy of ketamine in male mice.

IBRO neuroscience reports December 1, 2024 Gabriela N Vaz, Flávia C Turcato, Isabel A V Lima et al.

Mice lacking the PI3Kγ gene did not respond to standard doses of ketamine or to classic antidepressants such as imipramine and fluoxetine, as measured by the forced swimming test. This unresponsiveness required a chronic deficiency of the PI3Kγ-mediated pathway, not just acute inhibition. The findings suggest PI3Kγ plays a role in antidepressant activity and may be involved in treatment resistance observed in some patients with major depressive disorder.

DOI: 10.1016/j.ibneur.2024.06.002 Full text Major depressive disorder Mdd Coping behavior Pi3kγ +7