Acute haloperidol increases impulse activity of brain noradrenergic neurons

Haloperidol (0.5 mg/kg, i.p.) increased impulse activity of every noradrenergic locus coeruleus neuron tested in chloral hydrate anesthesized rats. Mean discharge rate increased from 1.4 +/- 0.2 Hz before to 2.7 +/- 0.4 Hz at 45 min after injection, with significantly increased activity occurring by 15 min post-drug. Elevated activity was apparent for at least 2 h following haloperidol. These results reveal that haloperidol has profound effects on brain noradrenergic neurons, indicating a possible site of action for effects of this neuroleptic agent.