Chunk #15 — Activation of metabotropic glutamate receptors (mGluRs) or muscarinic Ach receptors (mAchRs) induces rhythmic bursting at α/θ frequencies in TC neurons
Because several other types of receptors on TC neurons are also negatively coupled to leak K+ channels (McCormick 1992), we recently asked whether their activation might also lead to HT bursting in TC neurons. In particular, we were interested to test whether or not pharmacologically activating muscarinic Ach receptors (mAchRs), which play a central role in arousal regulation through their effects in the thalamocortical system (McCormick 1992), would have similar effects on TC neuron firing to activating mGluRs. Indeed, through an effect largely mediated by M1/M3 receptors, the ACh receptor agonist carbachol (Cch) applied in vitro brings about HT bursting at ~3–15 Hz in subsets of TC neurons from a variety of principal thalamic nuclei including the LGN, VB and VL (Fig. 2) as well as from the centrolateral (CL) nucleus, a member of the non-specific intralaminar nuclei (data not shown).
