Sleep pattern and learning in knockdown mice with reduced cholinergic neurotransmission

Autor(es)

C.M. Queiroz ^{[1, 2, 3]} ; P.A. Tiba ^{[1, 4]} ; K.M. Moreira ^[1] ; P.A.M. Guidine ^[5] ; G.H.S. Rezende ^[5] ; M.F.D. Moraes ^[5] ; M.A.M. Prado ^{[6, 7]} ; V.F. Prado ^{[6, 7]} ; S. Tufik ^[1] ; L.E. Mello ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo, Dept Psicobiol, Sao Paulo - Brazil

^[2] Univ Fed Sao Paulo, Dept Fisiol, Sao Paulo - Brazil

^[3] Univ Fed Rio Grande do Norte, Inst Cerebro, BR-59072970 Natal, RN - Brazil

^[4] Univ Fed ABC, Ctr Matemat Comp & Cognicao, Santo Andre, SP - Brazil

^[5] Univ Fed Minas Gerais, Dept Fisiol & Biofis, Belo Horizonte, MG - Brazil

^[6] Univ Western Ontario, Dept Physiol & Pharmacol, Robarts Res Inst, Mol Brain Res Grp, London, ON - Canada

^[7] Univ Western Ontario, Dept Anat & Cell Biol, London, ON - Canada

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 46, n. 10, p. 844-854, 2013-10-00.

Resumo

Impaired cholinergic neurotransmission can affect memory formation and influence sleep-wake cycles (SWC). In the present study, we describe the SWC in mice with a deficient vesicular acetylcholine transporter (VAChT) system, previously characterized as presenting reduced acetylcholine release and cognitive and behavioral dysfunctions. Continuous, chronic ECoG and EMG recordings were used to evaluate the SWC pattern during light and dark phases in VAChT knockdown heterozygous (VAChT-KDHET, n=7) and wild-type (WT, n=7) mice. SWC were evaluated for sleep efficiency, total amount and mean duration of slow-wave, intermediate and paradoxical sleep, as well as the number of awakenings from sleep. After recording SWC, contextual fear-conditioning tests were used as an acetylcholine-dependent learning paradigm. The results showed that sleep efficiency in VAChT-KDHET animals was similar to that of WT mice, but that the SWC was more fragmented. Fragmentation was characterized by an increase in the number of awakenings, mainly during intermediate sleep. VAChT-KDHET animals performed poorly in the contextual fear-conditioning paradigm (mean freezing time: 34.4±3.1 and 44.5±3.3 s for WT and VAChT-KDHET animals, respectively), which was followed by a 45% reduction in the number of paradoxical sleep episodes after the training session. Taken together, the results show that reduced cholinergic transmission led to sleep fragmentation and learning impairment. We discuss the results on the basis of cholinergic plasticity and its relevance to sleep homeostasis. We suggest that VAChT-KDHET mice could be a useful model to test cholinergic drugs used to treat sleep dysfunction in neurodegenerative disorders. (AU)

• Processo FAPESP: 98/14303-3 - Center for Sleep Studies
• Beneficiário: Sergio Tufik
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs