Analysis of Cortical Spread Depression in Rats Induced to Hyperprolactinemia and Treated with Melatonin

Abstract

Introduction: Cortical spreading depression (CSD) is an electrophysiological phenomenon used experimentally to analyze the direct modulation of the electrical activity of cortical neurons, and the dissemination of this wave may be associated with several pathological factors. Hyperprolactinemia is a pathological condition related to high plasma levels of prolactin, which, at normal levels, influences brain functions. However, high levels of this hormone can act differently in the cerebral cortex. Melatonin is an influential hormone in the central and peripheral nervous system, playing a cerebrovascular, neuroendocrine, neuroimmune and neuroprotector regulatory role. Objectives: The objective was to analyze CSD in rats induced to hyperprolactinemia and treated with melatonin. Results: 64 rats were used, which were divided into two treatment periods (30 and 60 days), subdivided into 4 groups each: Control, Vehicle, Hiper (rats induced to hyperprolactinemia) and Hiper+mel (rats induced to hyperprolactinemia and treated with melatonin). After treatment, the animals were anesthetized for analysis of the CSD propagation velocity, which was calculated based on the distance between the two recording electrodes, and the time spent by the CSD to cover this distance. The recording was performed at the two parietal points of the right cerebral hemisphere, for a continuous period of 4 hours. The ANOVA results of the animals treated for 30 days showed that the control group had an average speed of 3.43 ± 0.11 mm/min and the vehicle 3.10 ± 0.04 mm/min. In the Hyper group, the mean speed was 3.38 ± 0.16 mm/min, while the Hyper+mel group had a speed of 2.21 ± 0.02 mm/min. As for the animals treated for 60 days, the control group obtained a speed of 3.21 ± 0.22 mm/min, while the vehicle 3.06 ± 0.17 mm/min. The hyper group 4.65 ± 0.16 mm/min and the hyper+mel 2.34 ± 0.19 mm/min. There was a significant increase in the hyper group compared to the others, and a significant decrease in the hyper+mel group compared to the other groups. Conclusions:It is concluded that hyperprolactinemia has a direct effect on increasing the speed of CSD, on the other hand, the neuroprotective effects of melatonin were sufficient to establish efficiency against hyperprolactinemia.