Age changes in number of pigmented neurons on the monkey locus coeruleus
Neurological Research Laboratory, Bartholin Institute, Kommunehospitalet, 1399 Copenhagen K, and Stereological Research Laboratory, Aarhus University, Denmark
Dept. of Neurology/S 91, the Cleveland Clinic Foundation, Cleveland, Ohio, USA
Neurological Research Laboratory, Bartholin Institute, Kommunehospitalet, 1399 Copenhagen K, and Stereological Research Laboratory, Aarhus University, Denmark
Abstract
Using stereological counting methods, the total number of pigmented and non-pigmented nerve cells was estimated in locus coeruleus of 19 rhesus monkeys: 13 old animals (10 females, three males), and six young females. Statistically, the total cell number was not different in young and old animals: 47,700 (coefficient of variation (CV = SD/mean) = 0.30) in young and 53,200 (CV = 0.64) in old monkeys; thus, no loss of neurons was found as a function of age. Young monkeys had an average of 1,600 (CV = 1.49) pigmented neurons, while the old anmials had 10,600 (CV = 1.16) pigmented neurons in locus coeruleus, so increased pigmentation is a function of age. The number of nonpigmented cells was almost the same in the two groups (young animals 46,100 (CV = 0.39) and old animals 42,600 (CV = 0.81). Locus coeruleus volume was the same in young and old animals, and there were no statistically significant systematic right-left differences in the number of pigmented and nonpigmented neurons. Relatively few age-related changes have previously been confinned in primates.