Journal of chemical neuroanatomy
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J. Chem. Neuroanat. · Jan 2013
Hypothalamic melanin-concentrating hormone projections to the septo-hippocampal complex in the rat.
Melanin-concentrating hormone (MCH) and neuropeptide glutamic acid-isoleucine (NEI) are expressed in neurons that are located mainly in the hypothalamus and project widely throughout the rat central nervous system. One of the main targets of melanin-concentrating hormone is the hippocampal formation, although the exact origin of the projections is unknown. By using injections of the retrograde tracer True Blue into the hippocampus, together with immunohistochemical analysis, we observed retrogradely labeled melanin-concentrating hormone-containing neurons in the lateral hypothalamic area, incerto-hypothalamic area, perifornical area, the periventricular nucleus of the hypothalamus, and in the internuclear area (between the dorsomedial and ventromedial nuclei of the hypothalamus), as well as a few retrogradely labeled and melanin-concentrating hormone-immunoreactive cells in the supramammillary nucleus. ⋯ Finally, using two different protocols for immunoperoxidase, we were able to show GABAergic basket cells presumably innervated by melanin-concentrating hormone-immunoreactive fibers in the hippocampal formation. On the basis of the data collected herein, we hypothesize that the MCH/NEI projections from hypothalamic nuclei participate in spatial memory and learning through direct and indirect pathways. These pathways would enable the animal to organize its exploratory behavior during foraging.
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J. Chem. Neuroanat. · Jan 2013
Developmental changes of calretinin immunoreactivity in the anterior thalamic nuclei of the guinea pig.
This study describes for the first time the distribution of the calcium-binding protein calretinin (CR) in the anterior thalamic nuclei (ATN) of the guinea pig during development. Brains from animals ranging from 40th embryonic day (E40) to 80th postnatal day (P80) were used in the study. No CR-immunoreactive (CR-ir) perikarya were present among the ATN at E40, but thick bundles of fibers containing CR were crossing the anteromedial nucleus (AM). ⋯ The ATN of newborns (P0) already showed an adult-like CR distribution pattern - perikarya in the AM and AV were distributed more homogenously and their number was slightly decreased in comparison to E60. The anterodorsal nucleus (AD) was devoid of CR-ir neurons in all studied stages. In conclusion, our results demonstrate that calretinin appears for the first time in neurons of various anterior thalamic nuclei of the guinea pig between 40th and 60th day of prenatal development.
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J. Chem. Neuroanat. · Jan 2013
The role of calcitonin gene-related peptide on the increase in transient receptor potential vanilloid-1 levels in trigeminal ganglion and trigeminal nucleus caudalis activation of rat.
Calcitonin gene-related peptide (CGRP) and transient receptor potential vanilloid-1 (TRPV1) play an important role in the development of pain and migraine pathogenesis. Increase in plasma CGRP levels is associated with delayed migraine-like attacks in migraine patients. Although several lines of evidence have indicated a key role of CGRP in migraine pain, its mechanisms remain unclear. ⋯ The number of small and medium TRPV1 and CGRP positive immunostaining neurons accompanying with co-localization of TRPV1 with CGRP neurons were significantly increased in TG of CGRP-injected rats. The sustained increase in c-Fos expression in TNC neurons was also observed in CGRP-injected rats. These results indicate that CGRP may participate in trigeminal nociceptive system sensitization by induced increase in TRPV1 and CGRP levels in TG neurons and activation of the central neurons in TNC.
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J. Chem. Neuroanat. · Jan 2013
Axonal anatomy of molecular layer heterotopia of the cerebellar vermis.
C57BL/6 mice and closely related strains exhibit heterotopia in the molecular layer of folia VIII and IX of the cerebellar vermis. Previously, we demonstrated that heterotopia are composed primarily of granule cells, Golgi cells, and GABAergic interneurons and are indicative of neuronal migration defect. In the present report we use immunocytochemistry and Thy1-YFP reporter mice to reveal the axonal constituents of cerebellar heterotopia which include mossy fibers, as well as serotonergic, cholinergic, and catecholaminergic axons. These data are relevant toward understanding of the mechanisms of axonal targeting during normal and abnormal cerebellar development.