Characterization of pars intermedia connections in amphibians by biocytin tract tracing and immunofluorescence aided by confocal microscopy.
Biocytin, recently introduced in neuroanatomical studies, was used as a retrograde tract tracer in combination with immunofluorescence in order to analyse the neurochemical characters of some central neuronal projections to the pars intermedia in two amphibian species, the anuran Rana esculenta and the urodele Triturus carnifex. After biocytin insertions in the pars intermedia, neurons became retrogradely labelled in the suprachiasmatic hypothalamus and the locus coeruleus of the brainstem in both species. Some scattered biocytin-labelled neurons were observed in the preoptic area. Moreover, working on the same sections, immunofluorescence revealed a number of codistributions and, in some cases, colocalization in the same neurons of biocytin labellings and immunopositivity for (1) tyrosine hydroxylase in the suprachiasmatic hypothalamus and the locus coeruleus of Rana and Triturus, (2) gamma-aminobutyric acid in the suprachiasmatic hypothalamus of Rana and Triturus and (3) neuropeptide Y in the suprachiasmatic hypothalamus of Rana. The specificity of such colocalizations was fully confirmed using dual-channel confocal laser scanning microscopy analysis.
Jansen
K
K
Dipartimento di Biologia Animale, Laboratorio di Anatomia Comparata, Università di Torino, Via Accademia Albertina 17, I-10123 Torino, Italy.
Fabro
C
C
Artero
C
C
Feuilloley
M
M
Vaudry
H
H
Fasolo
A
A
Franzoni
M F
MF
D000344:Afferent Pathways / Q000737:chemistry / Q000648:ultrastructure; D000818:Animals; D001370:Axonal Transport; D004396:Coloring Agents; D019084:Fluorescent Antibody Technique, Indirect; D008125:Locus Coeruleus / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D008239:Lysine / Q000031:analogs & derivatives; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence / Q000379:methods*; D009419:Nerve Tissue Proteins / Q000032:analysis; D009478:Neuropeptide Y / Q000032:analysis; D010904:Pituitary Gland, Posterior / Q000737:chemistry / Q000294:innervation*; D011301:Preoptic Area / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D011893:Rana esculenta / Q000033:anatomy & histology*; D013045:Species Specificity; D013493:Suprachiasmatic Nucleus / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D014319:Triturus / Q000033:anatomy & histology*; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis; D005680:gamma-Aminobutyric Acid / Q000032:analysis
D004396:Coloring Agents; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D005680:gamma-Aminobutyric Acid; D014446:Tyrosine 3-Monooxygenase; C013411:biocytin; D008239:Lysine