Muscarinic and Nicotinic Modulation of Thalamo-Prefrontal Cortex Synaptic Pasticity In Vivo

Autor(es)

Bueno-Junior, Lezio Soares ^[1] ; Lopes-Aguiar, Cleiton ^[1] ; Ruggiero, Rafael Naime ^[1] ; Romcy-Pereira, Rodrigo Neves ^{[2, 1]} ; Leite, Joao Pereira ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Neurosci & Behav Sci, Ribeirao Preto Sch Med, Sao Paulo - Brazil

^[2] Univ Fed Rio Grande do Norte, Inst Brain, BR-59072970 Natal, RN - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 7, n. 10 OCT 30 2012.
• Citações Web of Science: 16

Resumo

The 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/mu L), the nicotinic agonist nicotine (NIC; 320 nmol/mu L), 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. (AU)

• Processo FAPESP: 05/56447-7 - Pesquisa através de imagens por ressonância magnética de alto campo destinadas a estudos em humanos
• Beneficiário: João Pereira Leite
• Modalidade de apoio: Auxílio à Pesquisa - Programa CINAPCE - Temático
• Processo FAPESP: 08/57413-7 - Plasticidade sináptica no córtex pré-frontal induzida por estimulação do tálamo mediodorsal de ratos in vivo: efeitos da modulação colinérgica muscarínica e nicotínica
• Beneficiário: Lézio Soares Bueno Júnior
• Modalidade de apoio: Bolsas no Brasil - Doutorado