Bcl-2/Bax Expression Levels Tend to Influence AMPAergic Trafficking Mechanisms During Hibernation in Mesocricetus auratus

Hypothermia is a physiological condition assuring brain protection against hypoxic-related damages. In this context, investigations carried out on the facultative hibernator Mesocricetus auratus proved to be very useful for establishing the type of neurosignaling role exerted by cerebral α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) subtypes during hypoxic/reperfusion injuries of the entrance (EN), torpor (TORP), and arousal (AROU) hibernating states. From the evaluation of the major AMPARs (GluR1 and GluR2), together with their scaffold proteins synapse-associated protein 97 kDa (SAP97) and PICK1, it resulted that GluR1 and SAP97 were mostly upregulated during the hypotensive (EN and TORP) states of the brainstem, amygdala, and hypothalamus, sites which are implicated with cardiovascular, motor, and sleep–wake events. In addition, elevated expression densities of the pro-apoptotic factor Bcl-2-associated X protein (Bax) resulted to be correlated to marked amino–cupric–silver stain signals during both hibernating states. Conversely, an increase of the neuroprotective factor GluR2, together with PICK1 and the anti-apoptotic B cell lymphoma 2 (Bcl-2), appeared to be linked with reduced argyrophilic signals in most of the above areas of the hypertensive AROU state. These first indications highlight distinct protective/degenerative measures of the above factors constituting key on/off switches during the various hibernating states that may provide potential therapeutic bearings on sleeping disorders.