I-2-Imidazoline receptors and monoamine oxidase B enzyme sites in human brain: covariation with age

An association between monoamino oxidase B enzyme (MAO-B) sites and I-2-imi dazoline receptors (I-2-IR) has been established in human brain on the basi s of correlational studies of radiolabelled binding sites. Because both MAO -B and Il-IR densities increase with aging, the age at death could be parti ally involved in the observed correlations. The evaluation of two independe nt but similar datasets demonstrated that the linear correlation between MA O-B and la-IR densities dropped from 0.70 (P = 0.02) and 0.41 (P = 0.14) in the crude analyses to the negligible values of 0.07 (P = 0.84) and 0.09 (P = 0.75) when the age at death was controlled for in the statistical analys es. The results lead to conclude, contrary to former interpretations, that there is not any statistical association linking both MAO-B catalytic unit sites and Ip-IR densities in the human brain. (C) 2000 Elsevier Science Ire land Ltd. All rights reserved.