Banisteriopsis; Callithrix; Somatosensory Cortex; Depressive Disorder Major.

Mood disorders such as depression are among the most common neuropsychiatric illnesses in humans, yet little is known about their neurobiology. The objective of this study was to assess the effects of Ayahuasca on the treatment of depression using morphoquantitative parameters in the primary somatosensory cortex of marmosets (Callithrix jacchus). The experimental animal used in the study was the marmoset, validated as a translational animal model of juvenile depression. Specimens were obtained through the Primate Center at UFRN. The entire process was overseen by a veterinarian, and the research was authorized by the Committee on Ethics in Animal Use (CEUA). For the results, six animals were randomly assigned to three groups: 2 in the family group (GF), 2 in the isolated group (GI), and 2 in the treated group (GT), aged 7 to 9 months at the start of the experiment, classified as juvenile I and II. The animals in the FG represented the positive control; those in the GI constituted the negative control group, and those in the GT formed the experimental group. The animals received Ayahuasca tea, provided by the Department of Physiology at UFRN, via gavage. Perfusion, craniotomy, and microtomy were performed. Subsequently, the obtained sections were stained using the Nissl technique, with thionin as the dye. Cavalieri's method was employed in stereology to analyze the volumes of areas in the primary somatosensory cortex (A3A, A3B, A1/2) among the animal groups (GF, GI, GT). The GT exhibited the largest volumes in all areas, with the A1/2 area showing the highest volumes in all groups. In contrast, the GF consistently displayed the smallest volumes.