Detection of nitric oxide synthase (NOS) immunoreactive neurons in the human septal area: a matter of method?
There is a remarkable discrepancy between biochemical and cell morphological findings with regard to the presence of NADPH diaphorase/neuronal nitric oxide synthase (NOS) in the primate septal area. Whereas considerable concentrations of neuronal nitric oxide synthase and high enzyme activities have been measured in postmortem human septal nuclei, histochemical studies were either unable to detect any nitric oxide synthase immunoreactivity in primate septal neurons, or found only a very few nitrergic neurons in this region. This study aimed to investigate the possible presence of nitrergic neurons in human the septal region in greater detail. After having studied a total of 16 postmortem human brains we conclude that the immunohistochemical demonstration of nitric oxide synthase in human septal neurons is largely dependent on the mode of tissue handling: in brain specimens which were fixed en-bloc with paraffin and embedded in paraplast, nitric oxide synthase immunoreactivity is barely detectable, whereas a satisfying immunostaining is obtained on free-floating frozen sections after an immersion-fixation with 4% paraformaldehyde and 0.5% glutaraldehyde, followed by sucrose protection of the specimens. We show herein that there are indeed nitric oxide synthase-containing neurons in the human septum, thus supporting results from previous biochemical studies.
Bernstein
Hans-Gert
HG
Department of Psychiatry, University of Magdeburg, Leipziger Street 44, D-39120 Magdeburg, Germany. Hans-Gert.Bernstein@medizin.uni-magdeburg.de
Brisch
Ralf
R
Ogonlade
Vera
V
Heinemann
Arndt
A
Baumann
Bruno
B
Arendt
Thomas
T
Dobrowolny
Henrik
H
Bogerts
Bernhard
B
Lüth
Hans-Joachim
HJ
D016477:Artifacts; D003451:Cryoprotective Agents; D020667:Diagonal Band of Broca / Q000166:cytology / Q000201:enzymology; D005260:Female; D005557:Formaldehyde; D005976:Glutaral; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008867:Microtomy / Q000379:methods; D008875:Middle Aged; D009252:NADPH Dehydrogenase / Q000378:metabolism; D026602:Nitrergic Neurons / Q000166:cytology / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D011108:Polymers; D011180:Postmortem Changes; D020665:Septum of Brain / Q000166:cytology / Q000201:enzymology*; D013045:Species Specificity; D016610:Tissue Embedding / Q000379:methods; D016707:Tissue Fixation / Q000379:methods*
D003451:Cryoprotective Agents; D011108:Polymers; D005557:Formaldehyde; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase; D005976:Glutaral; C003043:paraform