Dopamine (DA) is a key neurotransmitter in the carotid body (CB), but its role in chemosensory responses remains nebulous. Recently, we found that the accumulation of a lipophilic derivative of DA, N-oleoyl-dopamine (OLDA) in the CB is 3-fold higher than that of DA proper. In the present study we seek to determine the effects of OLDA on ventilation and its responses to hypoxia. The study was performed on male Wistar rats, anesthetized, paralyzed, vagotomized, and ventilated. Ventilation was recorded from the phrenic neurogram. The protocol consisted of taking the ventilatory responses to 14% and 11% O2 in N2, before and then 20 min after administration of OLDA (20 mg/kg; ip). CO2 was kept constant. We found that OLDA had a depressant effect on hypoxic ventilation. However, the peak hypoxic ventilatory stimulation decreased after OLDA by the same magnitude at the 14% and 11% hypoxia; the mean decreases were from 148 ±10(SE)% to 124 ±7% and from 163 ±10% to 141 ±11% of the baseline levels, respectively. Thus, OLDA inhibited the hypoxic ventilatory response, like exogenous DA does, but failed to change hypoxic sensitivity. We conclude that the OLDA compound is incorporated into DA-mediated signal transduction in carotid chemoreceptor cells. OLDA's potential to stabilize DA molecule in biomembranes may give rise to its sustained action, as opposed to the fleeting effects of DA proper.