Evidence of an inverse correlation between serotonergic activity and spreading depression propagation in the rat cortex

• Published in: Brain research 2017-10, Vol.1672, p.29-34
• Main Authors: Guedes, Rubem Carlos Araújo, Araújo, Maria das Graças Rodrigues de, Verçosa, Taciana Cristovam, Bion, Francisca Martins, de Sá, Andrea Lima, Pereira, Antônio, Abadie-Guedes, Ricardo
• Format: Article
• Language: English
• Subjects: Animals; Cerebral Cortex - metabolism; Cerebral Cortex - physiology; Cortical Spreading Depression - physiology; Depression - metabolism; Depression - physiopathology; Disease Models, Animal; Electric Stimulation; Electroencephalography; Epilepsy; Male; Migraine; Raphe nuclei; Raphe Nuclei - physiology; Rats; Rats, Wistar; Serotonergic Neurons - physiology; Serotonin; Serotonin - pharmacology; Serotonin - physiology; Spreading depression; Sumatriptan
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2017.07.011

•We studied spreading depression (SD) after serotonin activity-modulating treatments.•Serotonin-enhancing treatments were raphe stimulation and sumatriptan injection.•Serotonin-depleting treatment consisted of feeding a low-tryptophan diet.•Serotonin enhancing and depleting treatments inversely modulated SD propagation.•Altered serotonergic activity, as observed in neurological diseases, may modulate SD. Various neurological and psychiatric diseases lead to alterations in cortical serotonergic activity as one of their underlying processes. However, the electrophysiological implication of changes in serotonergic activity remains a matter of investigation. In this study, we investigated whether brain serotonergic activity influences the excitability-related phenomenon known as cortical spreading depression (CSD). CSD parameters (propagation velocity, and amplitude and duration of the DC-shift) was evaluated in rats that received two treatments that increased cortical serotonergic activity, electrical stimulation of the raphe nuclei and subcutaneous injection of a selective serotonin reuptake inhibitor, sumatriptan. A third group of rats was tested on a low-tryptophan diet rat model of serotonin depletion. Control rats for these three groups received, respectively, sham raphe stimulation, saline injection, and a tryptophan-supplemented diet. Compared to controls, electrical stimulation of the raphe nuclei and sumatriptan administration decelerated CSD and increased the duration of the negative DC-shift of CSD, whereas the low-tryptophan diet was associated with significantly accelerated CSD propagation and shortened DC-shift of CSD (p