title: Serotonin receptor antagonists increase fast ripple activity in rats treated with kainic acid.
abstract: Fast ripples (FR, 250-600 Hz) are field potentials that occur only in those areas capable of generating seizures, such as the hippocampus, and modulation of FR by serotonin has been reported. Therefore, we hypothesized that the receptor antagonists 5HT1A and 5HT2A, B, C will increase FR in rats treated with kainic acid (KA, 0.8 μg/0.5 μl). For this purpose, the intracranial EEG recordings of the hippocampus from animals treated with KA and the serotonin antagonists WAY100135 and ritanserin (dose 0.2mg/Kg, i.p) were analyzed. In addition, morphologic parameters were analyzed after staining samples with cresyl violet, Timm stain, NeuN and GFAP and observing immunofluorescence. The results showed an increase in the number of events of FR (p<0.0001) and duration of each FR event after the administration of WAY100135 (p<0.030). Additionally, there was an increase in the number of events of FR (p<0.0001) and amplitude of FR after ritanserin administration (p<0.014). In relation to changes in unspecified cells, there was a significant decrement in the width of the CA3 pyramidal layer of the hippocampus (p<0.001), and there were no significant changes in reactive glia and fiber sprouting. However, a slight gain of astrocytes marked with GFAP and larger astrocytes with more projections were observed. In conclusion, these results support the modulation of FR by serotonin with participation of the 5HT1A receptor as a possible mediator of the effect. However the exact mechanisms resulting in such effect is not known.
authors.affiliation: Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Jalisco, Mexico.
authors.forename: Carla
authors.initials: C
authors.lastname: García-Barba
authors.affiliation: Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Jalisco, Mexico. Electronic address: lauramedcej@gmail.com.
authors.forename: Laura
authors.initials: L
authors.lastname: Medina-Ceja
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D058256:Brain Waves / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007608:Kainic Acid / Q000494:pharmacology*; D008297:Male; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D016713:Ritanserin / Q000494:pharmacology; D012640:Seizures / Q000139:chemically induced* / Q000503:physiopathology*; D012702:Serotonin Antagonists / Q000494:pharmacology*
chemical_list: D018690:Excitatory Amino Acid Agonists; D005904:Glial Fibrillary Acidic Protein; D010879:Piperazines; D012702:Serotonin Antagonists; C081293:WAY 100135; D016713:Ritanserin; D010751:Phosphopyruvate Hydratase; D007608:Kainic Acid
keywords: 5HT(1A) receptor; 5HT(2) receptor; Fast ripples; Hippocampus; Kainic acid; Morphologic analysis