Frequency analysis of catecholamine axonal morphology in human brain. I. Effects of postmortem delay interval.
The diverse morphologies of catecholamine axons in the human brain were examined by using tyrosine hydroxylase immunocytochemistry. Human brain tissue was obtained by either rapid autopsy (mean postmortem delay < 1 h) or routine autopsy (mean postmortem delay 5 h). Tissue blocks from the superior frontal cortex (Brodmann area 9), the hippocampal gyrus and the calcarine cortex (Brodmann area 17) were processed for tyrosine hydroxylase immunoreactivity. First, a quantitative method was developed to reliably identify differing morphologies of catecholamine axons in human brain tissue. A total of 625 tyrosine hydroxylase immunoreactive axons were randomly sampled from coded sections and classified into one of six distinct morphological categories. These categories were based upon axonal morphologies which were readily distinguished by trained observers, and moreover, further investigations demonstrated that entire tissue sections could be reliably re-sampled at intervals of up to six months. Second, regional variations in axonal distribution and the effects of increasing postmortem delay in tissue processing on the categories of tyrosine hydroxylase immunoreactive axon morphologies were examined. Postmortem delays of up to 6.5 hours were found to decrease the frequency of fine axons with varicosities (axon type 2) and increase thick-caliber straight axons (axon type 5) in all regions examined. The frequency of other morphological axon types did not change as a function of postmortem delay. In summary, the use of quantitative neuroanatomical measures of the catecholaminergic system in human brain tissue was found to be reliable and valid. It was furthermore demonstrated that postmortem delays affect selected morphological types of catecholamine axons.(ABSTRACT TRUNCATED AT 250 WORDS)
Booze
R M
RM
Department of Pharmacology and College of Pharmacy, University of Kentucky Medical Center, Lexington 40536-0084.
Mactutus
C F
CF
Gutman
C R
CR
Davis
J N
JN
D000368:Aged; D000369:Aged, 80 and over; D001369:Axons / Q000502:physiology / Q000648:ultrastructure*; D001921:Brain / Q000648:ultrastructure*; D002395:Catecholamines / Q000502:physiology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011180:Postmortem Changes; D012044:Regression Analysis; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000276:immunology / Q000378:metabolism
D002395:Catecholamines; D014446:Tyrosine 3-Monooxygenase