Navegando por Autor "Bueno-Junior, Lezio Soares"
Agora exibindo 1 - 2 de 2
- Resultados por página
- Opções de Ordenação
Artigo Muscarinic and Nicotinic Modulation of Thalamo- Prefrontal Cortex Synaptic Pasticity In Vivo(2012-10-30) Bueno-Junior, Lezio Soares; Lopes-Aguiar, Cleiton; Ruggiero, Rafael Naime; Romcy-Pereira, Rodrigo Neves; Leite, João PereiraThe mediodorsal nucleus of the thalamus (MD) is a rich source of afferents to the medial prefrontal cortex (mPFC). Dysfunctions in the thalamo-prefrontal connections can impair networks implicated in working memory, some of which are affected in Alzheimer disease and schizophrenia. Considering the importance of the cholinergic system to cortical functioning, our study aimed to investigate the effects of global cholinergic activation of the brain on MD-mPFC synaptic plasticity by measuring the dynamics of long-term potentiation (LTP) and depression (LTD) in vivo. Therefore, rats received intraventricular injections either of the muscarinic agonist pilocarpine (PILO; 40 nmol/mL), the nicotinic agonist nicotine (NIC; 320 nmol/mL), or vehicle. The injections were administered prior to either thalamic high-frequency (HFS) or low-frequency stimulation (LFS). Test pulses were applied to MD for 30 min during baseline and 240 min after HFS or LFS, while field postsynaptic potentials were recorded in the mPFC. The transient oscillatory effects of PILO and NIC were monitored through recording of thalamic and cortical local field potentials. Our results show that HFS did not affect mPFC responses in vehicle-injected rats, but induced a delayed-onset LTP with distinct effects when applied following PILO or NIC. Conversely, LFS induced a stable LTD in control subjects, but was unable to induce LTD when applied after PILO or NIC. Taken together, our findings show distinct modulatory effects of each cholinergic brain activation on MD-mPFC plasticity following HFS and LFS. The LTP-inducing action and long-lasting suppression of cortical LTD induced by PILO and NIC might implicate differential modulation of thalamo-prefrontal functions under low and high input drive.Artigo Selective post-training time window for memory consolidation interference of cannabidiol into the prefrontal cortex: reduced dopaminergic modulation and immediate gene expression in limbic circuits(2017) Rossignoli, Matheus Teixeira; Lopes-Aguiar, Cleiton; Ruggiero, Rafael Naime; Silva, Raquel Araujo do Val da; Bueno-Junior, Lezio Soares; Kandratavicius, Ludmyla; Peixoto-Santos, José Eduardo; Crippa, José Alexandre; Hallak, Jaime Eduardo Cecilio; Zuardi, Antonio Waldo; Szawka, Raphael Escorsim; Anselmo-Franci, Janete; Leite, João Pereira; Romcy-Pereira, Rodrigo NevesThe prefrontal cortex (PFC), amygdala and hippocampus display a coordinated activity during acquisition of associative fear memories. Evidence indicates that PFC engagement in aversive memory formation does not progress linearly as previously thought. Instead, it seems to be recruited at specific time windows after memory acquisition, which has implications for the treatment of posttraumatic stress disorders. Cannabidiol (CBD), the major non-psychotomimetic phytocannabinoid of the Cannabis sativa plant, is known to modulate contextual fear memory acquisition in rodents. However, it is still not clear how CBD interferes with PFC-dependent processes during post-training memory consolidation. Here, we tested whether intra-PFC infusions of CBD immediately after or 5 h following contextual fear conditioning was able to interfere with memory consolidation. Neurochemical and cellular correlates of the CBD treatment were evaluated by the quantification of extracellular levels of dopamine (DA), serotonin, and their metabolites in the PFC and by measuring the cellular expression of activity-dependent transcription factors in cortical and limbic regions. Our results indicate that bilateral intra-PFC CBD infusion impaired contextual fear memory consolidation when applied 5 h after conditioning, but had no effect when applied immediately after it. This effect was associated with a reduction in DA turnover in the PFC following retrieval 5 days after training. We also observed that post-conditioning infusion of CBD reduced c-fos and zif-268 protein expression in the hippocampus, PFC, and thalamus. Our findings support that CBD interferes with contextual fear memory consolidation by reducing PFC influence on cortico-limbic circuits.