Mu-opioid receptors in the caudomedial NTS are critical for respiratory responses to stimulation of bronchopulmonary C-fibers and carotid body in conscious rats
The cmNTS presents the highest MORs in the caudal medulla. Activation of cmNTS MORs blocks or almost eliminates the PCF-mediated apnea and HVR in the intact rats with HCVR inhibited in the carotid body ablated rats. Our data imply a presence of MORs in the synapse of the 2nd-order neurons receiving inputs from PCFs and the carotid and NTS chemosensitive neurons.