Acute exposure of rabbit proximal tubule suspensions (PTs) to acid-base disturbances alters ErbB1 and ErbB2 tyrosine phosphorylation. Here we examine whether Src (which can transactivate ErbB1/2) or proteins downstream of ErbB1/2 are involved in the CO2/HCO3 signaling cascade. New Zealand White rabbits were euthanized under anesthesia using ~10ml intravenous 5% pentobarbital sodium. PTs were purified from rabbit renal cortex using a method similar to Doctor RB et al. (1998), modified for rabbit. We exposed purified PTs for 5 or 20 min to: HEPES (i.e., HEPES/pH 7.40); Butyrate (HEPES/pH 7.10 + 20 mM butyrate);EGF (‘HEPES’ + 10 nM EGF); Physiological CO2/HCO3 (5% CO2/22 mM HCO3/pH 7.40); respiratory acidosis (RAc; 10% CO2/22 mM HCO3/pH 7.10); compensated RAc (10% CO2/44mM HCO3/pH 7.40); metabolic acidosis (MAc; 5% CO2/11 mM HCO3/pH 7.10), respiratory alkalosis (RAlk; 2.5% CO2/22 mM HCO3/pH 7.70), or metabolic alkalosis (MAlk; 5% CO2/44 mM HCO3/pH 7.70) +/- PD168393, an ErbB family inhibitor. We probed lysates with phospho-specific (p) antibodies to ErbB1/ErbB2, Src, ERK1/2 (p44 & p42), and PLCγ1. PTs exposed to RAlk for 5 min exhibited a decreased ratio of Src-pY-416 (kinase-activating) to Src-pY-527 (kinase-inactivating). Concurrently ErbB1-pY845 (Src-transactivated) fell. RAlk or MAlk for 5 min reduced pERK1/2 levels compared to the other treatments; PD168393 inhibited only p44 after MAlk. At 5 min, butyrate, RAc, or Compensated RAc reduced PLCγ1-pY-783; at 20 min, pY for butyrate and RAc remained low. In conclusion, rabbit PTs exhibit acid-base-dependent signaling responses in pathways up- and downstream from ErbB1/2, and these signals evolve over time.