The acute response of the amygdalar TRH system to psychogenic stressors varies dependent on the paradigm and circadian condition.

Central administration of thyrotropin releasing hormone (TRH) reduces anxiety; amygdalar TRH expression is inversely proportional to the anxious behavior displayed in the elevated plus maze performed during the dark phase (EPM-D). To better understand the role of TRH in amygdala function, we evaluated the expression of TRH and the elements involved in its transmission in various stressful paradigms and how they associated with behavior. Wistar male rats were exposed to restraint (RES), EPM, or the open field test (OFT) and sacrificed 0-60 min afterwards; OFT, RES and EPM were performed during the light (L), and OFT during the dark phase. Restraint increased amygdalar levels of proCRH mRNA, without change in proTRH. All paradigms augmented corticosterone release, highest after OFT-L that also enhanced proCRH mRNA levels and decreased those of proTRH. OFT-D activated the TRH system. Levels of anxiety or locomotion were similar in animals tested in light or dark phases but their association with biochemical parameters differed. ProTRH expression and TRH release correlated positively with decreased anxiety in EPM-L and in OFT-D. No association with anxiety was detected in OFT-L where proCRH and proTRH expression correlated with locomotion supporting their involvement in arousal. The responses of TRH amygdalar systems appeared modulated by the extent of the stress response and by the circadian conditions. Increased proTRH expression of animals exposed to OFT-D was specifically observed in the cortical nucleus of the amygdala, area involved in processing fear stimuli; these TRH neurons may thus be part of a circuit with anxiolytic properties.

Racionalidad y medicina tradicional de las etnias indígenas en México. Propuesta de un marco conceptual para la comprensión de los conocimientos tradicionales en el contexto de la multiculturalidad / Rationality and traditional medicine of the indigenous ethnic groups in Mexico. Proposal of a conceptual framework for the understanding of traditional knowledge in the context of multiculturalism

Dilucidar la racionalidad de las creencias, acciones y conocimientos humanos ha sido un tema importante de reflexión en las ciencias sociales y en las humanidades. Esta reflexión ha adquirido nuevas resonancias y mayor complejidad, en lo que va del siglo XXI, en el contexto de la diversidad cultural y las demandas multiculturalistas. En México los estudios culturales, lejos de comprender las diferentes manifestaciones culturales y los criterios de racionalidad inmersos en su cosmovisión del mundo, han impuesto la noción moderna de racionalidad.