Locus coeruleus neurons in the neonatal rat: electrical activity and responses to sensory stimulation.

Newborn rats, 1-3 days of age, were anesthetized with urethane and single-unit activities were recorded extracellularly in the locus coeruleus. Ca. 35% of locus coeruleus neurons recorded were antidromically activated from stimulation of the frontal cortex. Although the majority of locus coeruleus neurons were not spontaneously active, non-noxious as well as noxious sensory stimuli such as touches to the skin, air puffs and tail pinches were very effective in exciting locus coeruleus neurons.