Nitroxidergic system in human trigeminal ganglia neurons: a quantitative evaluation.
The trigeminal ganglia are involved in transmission of orofacial sensitivity. The free radical gas nitric oxide (NO) has recently been found to function as a messenger molecule in both central and peripheral trigeminal primary afferent neurons. NO is produced within neurons mainly by two enzymes: a constitutive (neuronal) form of NO synthase (nNOS) or an inducible form of NOS (iNOS). The aim of the study was to evaluate the distribution of trigeminal neurons according to size (small, medium and large neurons) and to correlate the percentage of NOS-immunopositive neurons with regard to neuronal size. The results showed a significant relationship between the percentage of nNOS-immunopositive neurons and the size of neurons. Evaluation of the percentage of nNOS-immunopositive neurons showed that they constitute about 50% of the total number of neurons and that they are represented mainly as large-sized neurons. The iNOS immunolabelling was very faint in all neuronal types. Since the nitroxidergic system is well represented in human trigeminal ganglia, this study indicates that it could play a relevant role in trigeminal neurotransmission.
Borsani
Elisa
E
Division of Human Anatomy, Department of Biomedical Sciences and Biotechnologies, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
Giovannozzi
Sara
S
Boninsegna
Ramon
R
Rezzani
Rita
R
Labanca
Mauro
M
Tschabitscher
Manfred
M
Rodella
Luigi F
LF
D000368:Aged; D000369:Aged, 80 and over; D048429:Cell Size; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D026602:Nitrergic Neurons / Q000166:cytology* / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D012668:Trigeminal Ganglion / Q000166:cytology*
C496319:NOS2 protein, human; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II