RESUMO
Neurons in the superior cervical ganglia (SCG) are classified as rostral and caudal according to their regional locations. Although diverse phenotypes have been reported for these two subpopulations, differences in neuroplasticity, like long-term potentiation (LTP), have not been characterized. Here, we explored possible regional differences of LTP expression in rostral and caudal neurons of the SCG in control rats, Wistar and Wistar Kyoto (WKy), and in the spontaneously hypertensive rats (SHR) as a model of hypertension. We characterized the expression of gLTP evoked by a tetanic train (40â¯Hz, 3â¯s) in an in vitro SCG preparation. gLTP was recorded in rostral and caudal neurons at 8-weeks-old (wo) in Wistar rats, 6-wo and 12-wo in SHR and WKy rats. We found that gLTP was differentially expressed; gLTP was larger in caudal neurons in Wistar and adult WKy rats. In adult 12-wo hypertensive SHR, gLTP was expressed in caudal but not in rostral neurons. In contrast, in 6-wo pre-hypertensive SHR, gLTP was expressed in rostral but not in caudal neurons; while in 6-wo WKy, gLTP was expressed in caudal but not in rostral neurons. The lack of gLTP expression in caudal neurons of 6-wo SHR was not due to a GABAergic modulation because several GABA-A receptor antagonists failed to unmask gLTP. Data show that neuroplasticity, particularly gLTP expression, varied according to the ganglionic region. We propose that differential regional expression of gLTP may be correlated with selective innervation on different target organs.
Assuntos
Gânglios Simpáticos/efeitos dos fármacos , Potenciação de Longa Duração/efeitos dos fármacos , Neurônios/metabolismo , Gânglio Cervical Superior/metabolismo , Animais , Antagonistas de Receptores de GABA-A/farmacologia , Gânglios Simpáticos/metabolismo , Masculino , Neurônios/efeitos dos fármacos , Ratos Endogâmicos SHR , Ratos Wistar , Gânglio Cervical Superior/fisiopatologiaRESUMO
OBJECTIVE: The purpose of this study was to evaluate the relation between cognitive performance and white matter (WM) integrity in patients with temporal lobe epilepsy (TLE) with mesial temporal sclerosis (MTS). METHODS: We included 26 patients with TLE (10 right, 16 left onset) as well as 24 healthy controls matched for age, gender, and years of education. In addition to quantitative hippocampal volume and transverse relaxation (T2) evaluation, whole-brain WM was analyzed using fractional anisotropy (FA) maps, derived from the diffusion tensor model. Average FA values were obtained from 38 regions of interest (ROI) of the main WM fascicles using an atlas-based approach. All subjects underwent extensive coFignitive assessments, Wechsler Adult Intelligence Scale (WAIS-IV) and Wechsler Memory Scale (WMS-IV). Fractional anisotropy was correlated with neuropsychological scores, and group effects were evaluated. Finally, patients were clustered based on their cognitive performance to evaluate if clinical and structural variables relate to specific cognitive profiles. RESULTS: Patients had differential alterations in the integrity of the WM dependent on seizure laterality and presence of hippocampal sclerosis. Patients with TLE showed, on average, lower scores in most of the cognitive assessments. Correlations between cognition and WM followed specific trajectories per group with TLE, particularly in Left-TLE, in which we found a marked association between cognitive abilities and WM abnormalities. Cluster analysis of cognitive performance revealed three cognitive profiles, which were associated with the degree and spread of WM abnormalities. SIGNIFICANCE: White matter diffusion characteristics differ between patients, particularly in relation to seizure laterality and hippocampal damage. Moreover, WM abnormalities are associated with cognitive performance. The extent of WM alterations leads to disrupted cerebral intercommunication and therefore negatively affects cognition.