Rhythmic dendritic Ca2+ oscillations in thalamocortical neurons during slow non-REM sleep-related activity in vitro.
J Physiol
; 590(16): 3691-700, 2012 Aug 15.
Article
em En
| MEDLINE
| ID: mdl-22641775
ABSTRACT
The distribution of T-type Ca2+ channels along the entire somatodendritic axis of sensory thalamocortical (TC) neurons permits regenerative propagation of low threshold spikes (LTS) accompanied by global dendritic Ca2+ influx. Furthermore, T-type Ca2+ channels play an integral role in low frequency oscillatory activity (<14 Hz) that is a defining feature of TC neurons. Nonetheless, the dynamics of T-type Ca2+ channel-dependent dendritic Ca2+ signalling during slow sleep-associated oscillations remains unknown. Here we demonstrate using patch clamp recording and two-photon Ca2+ imaging of dendrites from cat TC neurons undergoing spontaneous slow oscillatory activity that somatically recorded δ (14 Hz) and slow (<1 Hz) oscillations are associated with rhythmic and sustained global oscillations in dendritic Ca2+. In addition, our data reveal the presence of LTS-dependent Ca2+ transients (Δ[Ca2+]) in dendritic spine-like structures on proximal TC neuron dendrites during slow (<1 Hz) oscillations whose amplitudes are similar to those observed in the dendritic shaft. We find that the amplitude of oscillation associated Δ[Ca2+] do not vary significantly with distance from the soma whereas the decay time constant (τdecay) of Δ[Ca2+] decreases significantly in more distal dendrites. Furthermore, τdecay of dendritic Δ[Ca2+] increases significantly as oscillation frequency decreases from δ to slow frequencies where pronounced depolarised UP states are observed. Such rhythmic dendritic Ca2+ entry in TC neurons during sleep-related firing patterns could be an important factor in maintaining the oscillatory activity and associated biochemical signalling processes, such as synaptic downscaling, that occur in non-REM sleep.
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Base de dados:
MEDLINE
Assunto principal:
Sono
/
Tálamo
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Células Dendríticas
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Córtex Cerebral
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Cálcio
Limite:
Animals
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article