Pacemaker calcium oscillations in thalamic astrocytes in situ.
During development, astrocytes in the ventrobasal thalamus display spontaneous intracellular calcium [Ca(2+)](i) oscillations, that can lead to the excitation of adjacent thalamocortical neurons via an NMDA receptor-mediated mechanism. In this study, we show that while astrocytes usually exhibit oscillations of irregular amplitude and frequency, a subset of spontaneously active thalamic astrocytes exhibits rhythmic, i.e. pacemaker, [Ca(2+)](i) oscillations with an average frequency of 0.019 Hz. This frequency of the pacemaker oscillations is close to the modal frequency of the irregularly oscillating astrocytes, suggesting that there is a preferred frequency for astrocytic [Ca(2+)](i) oscillations. If pacemaker [Ca(2+)](i) oscillations underlie excitatory signaling to neurons, the result would be rhythmic activation of thalamocortical neurons and astrocyte-driven synchronized oscillations within neurons of the thalamocortical loop.
Parri
H R
HR
School of Biosciences, Cardiff University, Museum Avenue, PO Box 911, Cardiff, CF10 3US, UK.
Crunelli
V
V
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D009924:Organ Culture Techniques; D051381:Rats; D013779:Tetrodotoxin / Q000494:pharmacology; D013788:Thalamus / Q000166:cytology*
D000779:Anesthetics, Local; D013779:Tetrodotoxin; D002118:Calcium