The locus coeruleus (LC) contains neurons that increase their firing rate (FR) in vitro when exposed to elevated CO₂/H⁺, and have been proposed to influence the respiratory network to make compensatory adjustments in ventilation. Prp57 transgenic mice express green fluorescent protein (GFP) in the LC and were used to isolate, culture and target LC neurons for electrophysiological recording. We hypothesized that GFP-LC neurons would exhibit CO₂/H⁺ chemosensitivity under primary culture conditions, evidenced as a change in FR. This is the first study to quantify CO₂/H⁺ responses in LC neuron FR in cell culture. Neurons were continuously bathed with solutions containing antagonists of glutamate and GABA receptors, and the acid/base status was changed from control (5% CO₂; ~pH 7.4), to hypercapnic acidosis (9% CO₂; ~pH 7.2) and hypocapnic alkalosis (3% CO₂; ~pH 7.6). FR was quantified during perforated patch current clamp recordings. ~86% of GFP-LC neurons were stimulated and ~14% were insensitive to changes in CO₂/H⁺. The magnitude of the response of these neurons depended upon the baseline FR, ranging from 155.9 ± 6% when FR started at 2.95 ± 0.49 Hz to 381 ± 55.6% when FR started at 1.32 ± 0.31Hz. These results demonstrate that cultured LC neurons from Prp57 transgenic mice retain functional sensing molecules necessary for CO₂/H⁺ responses. Prp57 transgenic mice will serve as a valuable model to delineate mechanisms involved in CO₂/H⁺ responsiveness in catecholaminergic neurons.