The effects of prolactin on the mesopontine tegmental neurons

In urethane‐anaesthetized rats, single neuronal activity was recorded extracellularily in and around the laterodorsal tegmental nucleus, and the response to prolactin applied by pressure injection was examined. Three of six cholinergic neurons tested were excited by prolactin for more than 1 min. In two of three non‐cholinergic neurons tested, prolactin application caused excitation which lasted a shorter time than that in the cholinergic neurons. The results suggest that prolactin may have physiological influences on these mesopontine neurons to increase paradoxical sleep.