Banca de DEFESA: Pedro Henrique Coelho Cordeiro

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Pedro Henrique Coelho Cordeiro
DATE: 31/03/2023
TIME: 14:00
LOCAL: Plataforma Microsoft Teams
TITLE:

Evaluation of the effects of NMDA receptor antagonists on intracerebral temperature, EEG and cardiac function

KEY WORDS:

Receptor NMDA; Temperatural intracerebral; EEG; ECG

PAGES: 100
BIG AREA: Ciências da Saúde
AREA: Medicina
SUMMARY:

Brain temperature variations are present in different neurophysiological functions and accompany pharmacological effects. One possible mechanism is changes in neurovascular coupling, which is the close relationship between neuronal activity and blood vessel volume with consequent variation in brain temperature. Ketamine (KET) and MK-801 (dizocilpine) are non-competitive glutamatergic NMDA receptor blockers. Both drugs produce similar electrophysiological effects, but with some marked differences, which may reflect differences in the mechanisms of action of these compounds. It is possible that the physiological and behavioral changes induced by NMDA channel blockers do not exclusively result from the pharmacodynamic interaction of these receptors, but depend on the correlated effects of brain temperature variation, correlates of brain electrical activity and cardiac function. In this study, we evaluated the physiological changes (intracerebral temperature, neural oscillations and cardiac activity) induced by these two drugs in rats anesthetized with isoflurane. Ten Wistar rats were used for analysis of temperature variation and cerebral oscillations, as well as cardiac function after acute administration of ketamine (30 mg/kg; n=5) and MK-801 (0.1 mg/kg; n= 5). The entire acquisition was performed after stereotaxic surgery for the insertion of a deep electrode in the CA1 region of the hippocampus together with the temperature sensor. A screw in the subdural region contralateral to the electrode was positioned for acquisition of the most superficial activity, and one in the cerebellum was used as a reference. A system (equipment and computer program) for measuring temperature in biomedical experiments was developed in the present work, as well as its validation in in vivo experiments. In addition to the apparatus, a protocol for acute measurement of temperature and brain electrical activity along with cardiac activity was established in the laboratory. From the acquisitions it was possible to observe that the brain temperature in anesthetized rats is lower than the body temperature, which is different in awake larger mammals. As well as corroborating with previous studies that brain temperature suffers small fluctuations when compared to body temperature, which is more homogeneous over time. It was confirmed that NMDA antagonists have a great influence on the dynamicity of brain rhythms and their administration in both cases decreased the animals' beats per minute. Finally, the acquisition approach of three physiological variables proved to be a metric with greater possibility of analysis at the systemic level of how drugs such as ketamine and MK-801 act.

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