PT  - JOURNAL ARTICLE
AU  - Stamenic, Tamara Timic
AU  - Todorovic, Slobodan M.
TI  - Cytosolic ATP Relieves Voltage-Dependent Inactivation of T-Type Calcium Channels and Facilitates Excitability of Neurons in the Rat Central Medial Thalamus
AID  - 10.1523/ENEURO.0016-18.2018
DP  - 2018 Jan 01
TA  - eneuro
PG  - ENEURO.0016-18.2018
VI  - 5
IP  - 1
4099  - http://www.eneuro.org/content/5/1/ENEURO.0016-18.2018.short
4100  - http://www.eneuro.org/content/5/1/ENEURO.0016-18.2018.full
SO  - eNeuro2018 Jan 01; 5
AB  - The central medial nucleus (CeM) is a part of the intralaminar thalamus, which is involved in the control of arousal and sensory processing. However, ionic conductances and mechanisms that regulate the activity of the CeM are not well studied. Here, we used in vitro electrophysiology in acute brain slices from adolescent rats to demonstrate that T-type calcium currents (T-currents) are prominent in the majority of the studied CeM neurons and are critical determinants of low-threshold calcium spikes (LTSs), which in turn regulate excitability of these neurons. Using an ATP-free internal solution decreased T-current density and induced a profound hyperpolarizing shift in steady-state inactivation curves while voltage-dependent activation kinetics were spared. Furthermore, selective pharmacological blockade of T-channels or use of an ATP-free solution reduced both tonic action potential (AP) frequency and rebound burst firing in CeM neurons. Our results indicate that T-channels are critical regulators of a thalamocortical circuit output and suggest that cytosolic ATP could be an endogenous regulatory mechanism in which T-channels may functionally gate sensory transmission and arousal in vivo.