The effect of dopamine on the rapidly adapting receptors in the dog lung

The effect of an infusion of dopamine (50 microg/kg per min) on both resting and histamine-stimulated discharge of rapidly adapting receptors has been studied in the dog lung. In dogs pretreated with propranolol and phentolamine (1 mg/kg) dopamine inhibited the ability of histamine to stimulate the rapidly adapting receptors. This inhibition was attenuated by sulpiride, a selective D(2)antagonist, (0.5 mg/kg i.v.). Dopamine did not affect the increases in R(L)or the falls in C(dyn)produced by histamine. It is suggested that dopamine may play a role in the control of lung function by reducing the ability of sensory nerves to produce harmful reflex activity.