Morphological characterization of spinal cord dorsal horn lamina I neurons projecting to the parabrachial nucleus in the rat.
J Comp Neurol
; 504(3): 287-97, 2007 Sep 20.
Article
em En
| MEDLINE
| ID: mdl-17640051
ABSTRACT
Many Rexed's lamina I neurons are nociceptive and project to the brain. Lamina I projection neurons can be classified as multipolar, fusiform, or pyramidal, based on cell body shape and characteristics of their proximal dendrites in the horizontal plane. There is also evidence that both multipolar and fusiform cells are nociceptive and pyramidal neurons nonnociceptive. In this investigation we identified which types of lamina I neurons belong to the spinoparabrachial tract in the rat and characterized them regarding the presence or absence of neurokinin-1 receptor (NK-1r) immunoreactivity. For this, cholera toxin subunit B (CTb), conjugated to a fluorescent marker was injected unilaterally into the parabrachial nucleus. Sections were additionally stained for the detection of NK-1r immunoreactivity and were examined using fluorescence and confocal microscopy. Serial confocal optical sections and 3D reconstructions were obtained for a considerable number of neurons per animal. Using immunofluorescence, we assessed the proportion of lamina I neurons belonging to the spinoparabrachial (SPB) tract and/or expressing NK-1r. The relative distribution of neurons belonging to the SPB tract was 38.7% multipolar, 36.8% fusiform, 22.7% pyramidal, and 1.9% unclassified. Most of the SPB neurons expressing NK-1r were either multipolar or fusiform. Pyramidal SPB neurons were seldom immunoreactive for NK-1r, an observation that provides further support to the concept that most lamina I projection neurons of the pyramidal type are nonnociceptive. In addition, our study provides further evidence that these distinct morphological types of neurons differ in their phenotypic properties, but not in their projection patterns.
Buscar no Google
Bases de dados:
MEDLINE
Assunto principal:
Ponte
/
Receptores da Neurocinina-1
/
Células do Corno Posterior
/
Dendritos
/
Neurônios Aferentes
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Comp Neurol
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Canadá