Fu C, Xue J, Wang R, Chen J, Ma L, Liu Y, Wang X, Guo F, Zhang Y, Zhang X, Wang S (2017) Chemosensitive Phox2b-expressing neurons are crucial for hypercapnic ventilatory response in the nucleus tractus solitarius. J Physiol 595:4973-4989.. doi: 10.1113/JP274437
Objective: To investigate whether paired-like homeobox 2b (Phox2b)-expressing NTS neurons are recruited in hypercapnic ventilatory response (HCVR) and whether these neurons exhibit intrinsic chemosensitivity.
Summary: Respiratory deficits caused by injection of SSP-SAP into the NTS are attributable to proportional lesions of CO2/H+-sensitive Phox2b-expressing neurons.
Usage: Two protocols were applied for SSP-SAP injections. In immunostaining experiments, to determine how many Phox2b-containing cells were destroyed, a total volume of 100 nl of PBS containing 6 ng of SSP-SAP (3 ng in 50 nl; 2 injections) was injected into one side of the NTS and the contralateral NTS was used as a control (no injection). For in vivo experiments, to determine whether loss of Phox2b cells led to impaired HCVR, bilateral injections with a total volume of 200 nl of PBS containing 6 ng (1.5 ng in 50 nl per injection; 2 injections per side) or 12 ng (3 ng in 50 nl per injection; two injections per side) of toxin into NTS. Breathing was studied in conscious, freely moving mice treated with SSP-SAP and Blank-SAP.