Altered Glutamate Receptor Expression Following Carotid Body Denervation in Goats
Federation of the American Society of Experimental Biology
After CBD, goats hypoventilate and their CO2 sensitivity is reduced for several days followed by a partial recovery (Pan et al, 1998). Even after partial recovery 30 days post-CBD, histochemical markers demonstrate a down regulation of the serotonergic system (Miller et al, EB 2012); thus, the mechanisms which contribute to the recovery of ventilation following CBD remain unclear. Recently, AMPA-type glutamate receptors have been implicated with a form of activity-dependent plasticity suggested to stabilize the output of neuronal networks (homeostatic plasticity) (Turrigiano and Nelson, 2004). Accordingly, to test the hypothesis that goats sacrificed 30 days post-CBD exhibit altered AMPA receptor expression, we quantified immunolabeled neuronal GluR2 optical density (OD) at sites that contribute to ventilatory control. Relative to a control goat (n=1), in CBD goats (n=3) we observed increased GluR2 OD within the nucleus tractis solitarii (NTS), decreased GluR2 OD within the midline raphé (MR), and no change in the dorsal motor nucleus of the vagus or the hypoglossal motor nucleus. These preliminary findings suggest that increased glutamatergic drive within the NTS is associated with the partial recovery of ventilation post-CBD and decreased glutamatergic drive within the MR may contribute to the down regulation of the serotonergic system.