Age-related characteristics of the neurotransmitter composition of neurons in the stellate ganglion.

The neurotransmitter composition of neurons in the stellate ganglion of rats of different ages (neonatal, 10, 20, 30, and 60 days) was studied by an immunocytochemical method using double labeling. Most neurons in rat pups of all age groups contained tyrosine hydroxylase. Most choline acetyltransferase-positive neurocytes in neonatal and 10-day-old rat pups were also tyrosine hydroxylase-positive. Only occasional cells in 30-and 60-day rat pups contained both of these enzymes. There were increases in the proportions of cells containing tyrosine hydroxylase and neuropeptide Y from birth to all time points of the study. In addition, there was a decrease in the proportion of somatostatin-positive neurons. The proportions of VIP-positive cells and choline acetyltransferase-containing neurons increased to age 10 days and then decreased. Somatostatin-positive neurons in all rat pups were small cells, while those containing choline acetyltransferase were large. Maturation of the neurotransmitter set in the rat stellate ganglion was complete by the end of the second month of life.