High performance liquid chromatography-based method to analyze activity of GABA transporters in central nervous system.

The GATs are the membrane proteins responsible for the uptake of GABA in the central nervous system. Alterations in GAT activity are implicated in several neurological diseases, including retinopathies. The present study describes an alternative method to determine GAT activity in tissue preparations of the central nervous system, using high performance liquid chromatography (HPLC) with fluorescence detection. The GABA concentration in the medium was determined using the o-phthaldehyde (OPA)-derivation protocol validated by the Brazilian Health Regulatory Agency (ANVISA) and the United States Food and Drug Administration (US-FDA). The GAT activity in the retinal preparations was determined through the evaluation of the GABA uptake, which was measured by assessing the difference between the initial and final concentrations of GABA in the incubation medium. The evaluation of the GAT kinetics returned values of Km = 382.5 ± 32.2 µM and Vmax = 34 nmol/mg of protein. The data also demonstrated that the GABA uptake was predominantly Na+- and temperature-dependent, and was also inhibited by incubation with nipecotic acid, a substrate of GABA transporters. Taken together, these findings confirm that our approach provided a specific measure of GAT activity in retinal tissue. The data presented here thus validate, for the first time, an alternative, simple and sensitive method for the evaluation of GAT activity using high performance chromatography on preparations of the central nervous system.

Physiotherapeutic evaluation and intervention proposal on a patient with post-chikungunya chronic arthritis.

BACKGROUND: Chikungunya fever is an arboviral disease characterized by a high morbidity rate related to intense and persistent arthralgia, causing a decrease in both quality of life (QoL) and productivity. This study aimed to report functional evaluation and multimodal physiotherapeutic intervention on a patient with post-chikungunya chronic arthritis (PCCA). CASE PRESENTATION: Woman, 47 years old, resident of the municipality of Belém, state of Pará, northern Brazil, with clinical diagnosis of chikungunya fever marked by fever, swelling, pain in the joints of the hands and feet, and headache. The physiotherapeutic treatment started three months after the diagnosis and consisted of 24 sessions composed of electrotherapy, thermotherapy, and kinesiotherapy resources. The patient progressed from an initial status of intense pain in several joints to low pain in a single joint and showed improvement in all domains of QoL, mainly in limitations by physical and emotional aspects and functional capacity. CONCLUSIONS: This case report details a proposal of multimodal physiotherapeutic intervention for a patient with functional impairments due to PCCA, suggesting that the use of physiotherapeutic resources may help this process and bring some assistance to those affected by the disease.

Adenosine A1 receptors modulate the Na+-Hypertonicity induced glutamate release in hypothalamic glial cells.

Glutamate release in response to a hypertonic stimulus is a well described phenomenon in the hypothalamus. Evidence suggests that hypothalamic glial cells release glutamate into the extracellular environment in hypertonic conditions. In the current study, we described autocrine regulation of adenosine on glutamate release induced by Na+hypertonicity in hypothalamic glial cell cultures. We showed that glial cells cultured from the cerebral cortex did not release glutamate or adenosine under hypertonic conditions. The findings suggest that the hypothalamus has specialized glial cells, which are responsive to osmotic variations. Stimulation or inhibition of adenosine A1 receptors modulates extracellular glutamate levels in hypothalamic glial cell cultures under hypertonic stimulation. Our results extend previous observations regarding the role of glial cells in the control of hypothalamic physiology. They further demonstrate for the first time that hypothalamic glial cells regulate Na+-hypertonicity-induced glutamate release by activation of adenosine A1 receptors via adenosine release.