The effect of loss of the glucose-monitoring neurons in the anterior cingulate cortex: Physiologic challenges induce complex feeding-metabolic alterations after local streptozotocin microinjection in rats

Modulatory effects of photobiomodulation in the anterior cingulate cortex of diabetic rats

Anterior Cingulate Cortex (ACC) has a crucial contribution to higher order pain processing. Photobiomodulation (PBM) has being used as integrative medicine for pain treatment and for a variety of nervous system disorders. This study evaluated the effects of PBM in the ACC of diabetic rats. Type 1 diabetes was induced by a single dose of streptozotocin (85 mg/Kg). A total of ten sessions of PBM (pulsed gallium-arsenide laser, 904 nm, 9500 Hz, 6.23 J/cm²) was applied to the rat peripheral nervous system. Glial fibrillary acidic protein (GFAP), mu-opioid receptor (MOR), glutamate receptor 1 (GluR1), and glutamic acid decarboxylase (GAD65/67) protein level expression were analyzed in the ACC of diabetic rats treated with PBM. Our data revealed that PBM decreased 79.5% of GFAP protein levels in the ACC of STZ rats. Moreover, STZ + PBM rats had protein levels of MOR increased 14.7% in the ACC. Interestingly, STZ + PBM rats had a decrease in 70.7% of GluR1 protein level in the ACC. Additionally, PBM decreased 45.5% of GAD65/67 protein levels in the ACC of STZ rats.

Disturbance of taste reactivity and other behavioral alterations after bilateral interleukin-1β microinjection into the cingulate cortex of the rat

The anterior cingulate cortex (ACC), is known to be intimately involved in food-related motivational processes and their behavioral organization, primarily by evaluating hedonic properties of the relevant stimuli. In the present study, the involvement of cingulate cortical interleukin-1β (IL-1β) mediated mechanisms in a) gustation associated facial and somato-motor behavioral patterns of Wistar rats were examined in taste reactivity test (TR). In addition, b) conditioned taste aversion (CTA) paradigm was performed to investigate the role of these cytokine mechanisms in taste sensation associated learning processes, c) the general locomotor activity of the animals was observed in open field test (OPF), and d) the potentially negative reinforcing effect of IL-1β was examined in conditioned place preference test (CPP). During the TR test, species specific behavioral patterns in response to the five basic tastes were analyzed. Response rates of ingestive and aversive patterns of the cytokine treated and the control groups differed significantly in case of the weaker bitter (QHCl, 0.03 mM), and the stronger umami (MSG, 0.5 M) tastes. IL-1β itself did not elicit CTA, it did not interfere with the acquisition of LiCl induced CTA, and it also failed to cause place preference or aversion in the CPP test. In the OPF paradigm, however, significant differences were found between the cytokine treated and the control groups in the rearing and grooming, the number of crossings, and in the distance moved. Our results indicate the involvement of cingulate cortical IL-1β mechanisms in the control of taste perception and other relevant behavioral processes.