DOPAMINE NEURON ONTOGENY - ELECTROPHYSIOLOGICAL STUDIES

The ontogeny of nigrostriatal dopamine (NSDA) neurons was examined with single‐unit extracellular electrophsiological methods. The physiological and pharmacological characteristic of 2‐, 4‐, and 5‐week‐old rat pup NSDA neurons were compared with those of adults (8–10 weeks old). Although the basal discharge rate, conduction velocity, and firing pattern of NSDA neurons from 4‐and 5‐week‐old rats were similar to adults, the 2‐week‐old‐rats differed significantly in all three of these physiological significanlty lower in the 2‐week‐old pups relative to adult. In addition, there were significantly fewer bursting NSDA neurons in 2‐week‐olds than there were in adults. Two and 4‐week‐olds exhibited significantly lower sensitivity to cumulative intravenous doses of apomorphine. In contrast, the sensitivity to cumulative intravenous doses of quinpirole was found to be similar across all age groups. It is evident that the pharmacological and physiological properites of NSDA neurons are in a dynamic state of flux during postnatal development. These electrophysiological findings are discussed in the context of the perinatal development of midbrain DA systems. Copyright © 1990 Wiley‐Liss, Inc.