Changes in the electrical activity of locus coeruleus neurons in pregnant rats

Under urethane anesthesia, unit activity of locus coeruleus (LC) neurons was recorded extracellularly in pregnant and non-pregnant rats. The spontaneous firing of LC neurons was found to be reduced in pregnant rats. In addition, biochemical studies indicated that noradrenaline contents in the cerebral cortex, one of the major projection sites of LC neurons, were significantly higher in pregnant than non-pregnant rats. These results suggest that the electrical activity of noradrenergic neurons in the LC is reduced during gestation.