Postnatal development of cholinergic afferents from the pedunculopontine tegmental nucleus to the lateralis medialis-suprageniculate nucleus of the feline thalamus.
The lateralis medialis-suprageniculate nuclear complex (LM-Sg) has been shown to receive cholinergic fibers from the pedunculopontine tegmental nucleus (PPT). The majority of terminals of these cholinergic fibers make simple synaptic contact with dendritic profiles, whereas some make contacts with the dendrites of projection neurons and GABAergic interneurons forming a glomerular synaptic complex. In the present study, we investigate the postnatal development of glomerular synaptic complexes in the LM-Sg in association with terminals of the PPT-thalamic projection fibers. We examined the postnatal development of cholinergic innervation as well as GABAergic interneuron innervation in the LM-Sg using antibodies against ChAT and GABA, respectively. Although choline acetyltransferase (ChAT)-positive neurons already exist in the PPT at birth (P0), ChAT-positive fibers in the LM-Sg were observed only after P7. These ChAT-positive fibers gradually increased in number, and almost reached the adult level by postnatal day 28 (P28). GABA-positive interneurons were scattered throughout the LM-Sg at P0, increased in size gradually and reached adult size by P14. Immature glomerulus-like synaptic arrangements appeared at P14. Definite glomeruli, in which ChAT-positive terminals are present, were observed at P28. These results emphasize that interneurons in the LM-Sg grow by P14, and then make neural circuits with cholinergic innervation within the glomerulus by 3-4 weeks.
Division of Neurobiology and Anatomy, Department of Sensory and Integrative Medicine, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi, 951-8122 Niigata, Japan.
Tadayoshi
T
Kaiya
Kaeko
K
Hoshino
Masao
M
Norita
D000344:Afferent Pathways / Q000033:anatomy & histology / Q000737:chemistry / Q000254:growth & development*; D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers / Q000032:analysis; D002415:Cats; D002795:Choline O-Acetyltransferase / Q000032:analysis; D002799:Cholinergic Fibers / Q000737:chemistry / Q000502:physiology*; D007124:Immunoenzyme Techniques; D045042:Pedunculopontine Tegmental Nucleus / Q000033:anatomy & histology / Q000737:chemistry / Q000254:growth & development*; D020656:Posterior Thalamic Nuclei / Q000033:anatomy & histology / Q000737:chemistry / Q000254:growth & development*; D017729:Presynaptic Terminals / Q000737:chemistry / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000032:analysis
D015415:Biomarkers; D005680:gamma-Aminobutyric Acid; D002795:Choline O-Acetyltransferase