Dopa, catecholamines, and dopac were determined in superior cervical ganglia of 
albino rats. The average amount of dopa in ganglia of control animals was 
1.1--1.6 micrograms/g. The concentrations of catecholamines and dopac were 
similar to values reported by others. The tyrosine hydroxylase inhibitor 
alpha-methylparatyrosine methyl ester caused marked decrease in the dopa 
concentration in the ganglia. The effect of reserpine was less pronounced. The 
aromatic amino acid decarboxylase inhibitor NSD 1015 markedly increased the dopa 
concentration.