RAPID COMMUNICATION Localization of CCK Receptors in Thalamic Reticular Neurons: A Modeling Study

Sohal, Vikaas S., Charles L. Cox, and John R. Huguenard. changes, and the CCK8S response is blocked by the potasLocalization of CCK receptors in thalamic reticular neurons: a sium channel blocker Cs (Cox et al. 1995). However, voltmodeling study. J. Neurophysiol. 79: 2827–2831, 1998. In an age-clamp recordings in this study revealed a reversal potenearlier experimental study, intracellular recording suggested that tial for the CCK8S response that was significantly more cholecystokinin (CCK) suppresses a K conductance in thalamic hyperpolarized than the equilibrium potential of potassium. reticular (RE) neurons, yet the reversal potential of the CCK reHere we develop computational models based on intracellusponse, revealed using voltage clamp, was hyperpolarized signifilar data from RE neurons that demonstrate that suppression cantly relative to the K equilibrium potential. Here, biophysical of K conductance, gK, in model RE neurons can produce models of RE neurons were developed and used to test whether the experimentally observed CCK response but only under suppression of the K conductance, gK, can account for the CCK response observed in vitro and also to determine the likely site of specific conditions. One of these is that CCK must suppress CCK receptors on RE neurons. Suppression of gK in model RE gK in the dendrites of RE neurons. Suppression of dendritic neurons can reproduce the relatively hyperpolarized reversal potengK may regulate the firing mode of RE neurons and the tial of CCK responses found using voltage clamp if the voltage duration of intrathalamic oscillations. clamp becomes less effective at hyperpolarized potentials. Three