Journal of chemical neuroanatomy
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J. Chem. Neuroanat. · Jul 2012
VGF peptides upon osmotic stimuli: changes in neuroendocrine regulatory peptides 1 and 2 in the hypothalamic-pituitary-axis and plasma.
VGF or VGF nerve growth factor inducible is a protein that has been found to play a role in regulating energy homeostasis and metabolism. From VGF precursor derive two neuroendocrine regulatory peptides NERP-1 and NERP-2 that, intracerebroventricular (icv) injected, modulate the antidiuretic hormone (ADH) release. Thus, we investigated possible modulations of the NERPs and other VGF peptides (namely VGF C-terminus, TLQP and PGH) in the hypothalamic-pituitary-axis, adrenal gland and plasma upon osmotic stimuli. ⋯ By immunohistochemistry, the VGF peptides studied (apart from the TLQP peptides) were present in the hypothalamic and pituitary ADH containing neurons of the control rats, while using WD and SL rats, an immunostaining increase was selectively revealed for VGF C-terminus peptides in the hypothalamic neurons that produce ADH. All VGF changes found using SL rats disappeared after only 1h of rehydration. In conclusion, we hypothesize that NERPs may be involved in both autocrine and endocrine mechanisms important for the fluid balance.
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J. Chem. Neuroanat. · Mar 2012
Descending projections from the rostral ventromedial medulla (RVM) to trigeminal and spinal dorsal horns are morphologically and neurochemically distinct.
Neurons in the rostral ventromedial medulla (RVM) are thought to modulate nociceptive transmission via projections to spinal and trigeminal dorsal horns. The cellular substrate for this descending modulation has been studied with regard to projections to spinal dorsal horn, but studies of the projections to trigeminal dorsal horn have been less complete. In this study, we combined anterograde tracing from RVM with immunocytochemical detection of the GABAergic synthetic enzyme, GAD67, to determine if the RVM sends inhibitory projections to trigeminal dorsal horn. ⋯ These findings suggest that RVM neurons send predominantly GABAergic projections to spinal dorsal horn and provide direct input to postsynaptic neurons such as interneurons or ascending projection neurons. The RVM projection to trigeminal dorsal horn is more heavily targeted to dendrites and is only modestly GABAergic in nature. These anatomical features may underlie differences between trigeminal and spinal dorsal horns with regard to the degree of inhibition or facilitation evoked by RVM stimulation.
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J. Chem. Neuroanat. · Oct 2011
Microarray analyses of laser-captured hippocampus reveal distinct gray and white matter signatures associated with incipient Alzheimer's disease.
Alzheimer's disease (AD) is a devastating neurodegenerative disorder that threatens to reach epidemic proportions as our population ages. Although much research has examined molecular pathways associated with AD, relatively few such studies have focused on the disease's critical early stages. In a prior microarray study we correlated gene expression in hippocampus with degree of Alzheimer's disease and found close associations between upregulation of apparent glial transcription factor/epigenetic/tumor suppressor genes and incipient AD. ⋯ Additionally, the present analyses identified several previously undetected pathway alterations, including downregulation of molecules that stabilize ryanodine receptor Ca2+ release and upregulation of vasculature development. Conversely, we found a striking paucity of the upregulated changes in the putative glial and growth-related genes that had been strongly overrepresented in the prior mixed-tissue study. We conclude that FFPE tissue can be a reliable resource for microarray studies of brain tissue, that upregulation of growth-related epigenetic/transcription factors during incipient AD is predominantly localized in and around white matter (supporting our prior findings and model), and that novel alterations in vascular and ryanodine receptor-related pathways in gray matter are closely associated with incipient AD.
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J. Chem. Neuroanat. · Jul 2011
Altered expression of neuronal tryptophan hydroxylase-2 mRNA in the dorsal and median raphe nuclei of three genetically modified mouse models relevant to depression and anxiety.
Depression and anxiety are among the leading causes of societal burden. Abnormalities in 5-hydroxytryptamine (5-HT; serotonin) neurotransmission are known to be associated with depressive and anxiety symptoms. The rostral projections of brainstem dorsal (DRN) and median (MRN) raphe nuclei are the main sources of forebrain 5-HT. ⋯ Thus, there were significant decreases in TPH2 transcript levels in 5-HT transporter (5-HTT)-/- mutant mice, whereas increases were observed in the vesicular glutamate transporter 1 hemi knock out (VGLUT1+/-) and cannabinoid receptor 1 mutant (CB1R-/-) mice. Based on these findings, we suggest that TPH2 mRNA expression is under the influence of multiple messenger systems in relation to presynaptic and/or postsynaptic feedback control of serotonin synthesis that, 5-HTT, VGLUT1 and CB1R seem to be involved in these feedback mechanisms. Finally, our data are in line with previous reports suggesting that TPH2 activity within different raphe subregions is differentially regulated under specific conditions.
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J. Chem. Neuroanat. · Apr 2011
Evidence for cellular injury in the midbrain of rats following chronic constriction injury of the sciatic nerve.
Complex behavioural disabilities, as well as pain, characterise neuropathic pain conditions for which clinical treatment is sought. In rats, chronic constriction injury (CCI) of the sciatic nerve evokes, allodynia and hyperalgesia as well as three distinct patterns of disability, characterised by changes in social and sleep-wake behaviours: (i) Pain & Disability; (ii) Pain & Transient Disability and (iii) Pain alone. Importantly, the degree of allodynia and hyperalgesia is identical for each of these groups. ⋯ The anatomical location of TUNEL and cleaved-caspase-3 immunoreactive profiles in the midbrain was also identified. Rats with Pain & Disability showed: (i) pro-apoptotic ratios of Bax:Bcl-2 mRNAs; (ii) decreased HSP60 mRNA; (iii) increased iNOS and MEK2 mRNAs; (iv) TUNEL-positive profiles in the lateral and ventrolateral PAG; and (v) caspase-3 immunoreactive neurons in the mesencephalic nucleus of the trigeminal nerve. Cell death in these specific midbrain regions may underlie the disabilities characterising this subgroup of nerve-injured rats.