Journal of chemical neuroanatomy
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J. Chem. Neuroanat. · Sep 2009
Expression patterns of 5-HT receptor subtypes 1A and 2A on GABAergic neurons within the spinal dorsal horn of GAD67-GFP knock-in mice.
5-HT plays an important role in GABA transmission at the spinal cord level. The main purpose of the present article is to find out, which 5-HT receptor subtypes may be involved in the regulation of GABAergic transmission in the spinal dorsal horn, by using the combination of tissue RT-PCR, single-cell RT-PCR and double immunofluorescent staining on the GAD(67)-GFP knock-in mice. The present result showed that 5-HT(1A) receptor subtype mRNA was present on about half of GFP-positive GABAergic interneurons in the spinal dorsal horn, which suggests a role of 5-HT(1A) receptor in GABA-mediated modulation of nociception at the spinal cord level. However, it is unexpected that just a very limited sub-population of the total GABAergic interneurons express 5-HT(2A) receptor mRNA or proteins in the spinal dorsal horn, which suggests that the 5-HT(2A) receptor subtype may not be important for spinal GABAergic effects in nociceptive modulation.
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J. Chem. Neuroanat. · Oct 2008
Comparative StudyThalamic nuclei in the opossum Monodelphis domestica.
We investigated nuclear divisions of the thalamus in the gray short-tailed opossum (Monodelphis domestica) to gain detailed information for further developmental and comparative studies. Nissl and myelin staining, histochemistry for acetylcholinesterase and immunohistochemistry for calretinin and parvalbumin were performed on parallel series of sections. Many features of the Monodelphis opossum thalamus resemble those in Didelphis and small eutherians showing no particular sensory specializations, particularly in small murid rodents. ⋯ The medial geniculate body consists of three nuclei (medial, dorsal and ventral) that are cytoarchitectonically distinct and stain differentially for parvalbumin. The relatively large size of the MG and LGNd points to specialization of the visual and auditory systems in the Monodelphis opossum. In contrast to rodents, the lateral dorsal and lateral posterior nuclei in the opossum are poorly differentiated cytoarchitectonically.
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J. Chem. Neuroanat. · Sep 2013
Distribution of parvalbumin, calbindin and calretinin containing neurons and terminal networks in relation to sleep associated nuclei in the brain of the giant Zambian mole-rat (Fukomys mechowii).
To broaden the understanding of the neural control and evolution of the sleep-wake cycle in mammals, the distribution and interrelations of sleep associated nuclei with neurons and terminal networks expressing the calcium-binding proteins parvalbumin, calbindin and calretinin were explored in a rodent that lacks a significant visual system. The sleep-associated nuclei explored include the cholinergic basal forebrain and pontine nuclei, the catecholaminergic locus coeruleus complex, the serotonergic dorsal raphe nuclear complex, the hypothalamic orexinergic nuclei, and the thalamic reticular nucleus. Zambian mole-rat brains were sectioned and stained in a one in nine series for Nissl, myelin, choline acetyltransferase (ChAT), tyrosine hydroxylase (TH), serotonin (5HT), orexin (OrxA), calbindin (CB), calretinin (CR) and parvalbumin (PV). ⋯ Neurons and terminal networks associated with PV immunoreactivity were the most sparsely distributed in these nuclei, but were present in the majority of nuclei. The thalamic reticular nucleus had the highest density of PV+ neurons and terminal networks, while PV+ neurons were absent in the cholinergic pontine nuclei, and PV+ neurons and terminal networks were absent in the orexinergic nuclei. The increased presence of neurons and terminal networks expressing the calcium binding proteins in comparison to that seen in the laboratory rat, specifically in the brainstem, may account for the prominent muscle twitches during REM sleep previously observed in this subterranean African rodent.
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J. Chem. Neuroanat. · Dec 2013
Orexinergic innervation of urocortin1 and cocaine and amphetamine regulated transcript neurons in the midbrain centrally projecting Edinger-Westphal nucleus.
Orexin is a neuropeptide that has been implicated in several processes, such as induction of appetite, arousal and alertness and sleep/wake regulation. Multiple lines of evidence also suggest that orexin is involved in the stress response. When orexin is administered intracerebroventricular it activates the hypothalamic pituitary adrenal (HPA)-axis, which is the main regulator of the stress response. ⋯ We found that orexin immunoreactive axon terminals were juxtaposed to EWcp-Ucn1/CART neurons, which also expressed orexin receptor 1 mRNA. Furthermore, acute stress strongly activated the EWcp-Ucn1/CART neurons and increased plasma CORT in both WT littermates and orexin-KO mice, however no genotype effect was found on these indices. Taken together our data show that orexin in general is not involved in the animal's acute stress response (plasma CORT) and it does not play a direct role in shaping the response of EWcp-Ucn1 neurons to acute stress either.
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J. Chem. Neuroanat. · May 2009
Expression of mu- and delta-opioid receptors in song control regions of adult male zebra finches (Taenopygia guttata).
The opioid system is known to play a role in various aspects of learning and memory in diverse species of mammals and birds. Earlier studies have localized the endogenous opioids, met- and leu-enkephalin, in the song control regions of male zebra finches (Taenopygia guttata), a sexually dimorphic species of songbirds wherein only males sing. Recent research has shown that levels of enkephalin increase in some of the song control regions during singing and that blocking opioid receptors with the antagonist naloxone decreases the frequency of singing in songbirds. ⋯ However, HVC and RA neurons expressed marginally higher levels of mu-OR mRNA compared to the posterior nidopallium, which was confirmed by immunohistochemical localization. We also found that the dorsolateral subdivision of DLM (dorsolateral nucleus of the medial thalamus) demonstrated high levels of mu-OR immunoreactivity. Our results suggest that the ORs may be involved in modulating different aspects of vocalization and/or gating auditory input, as well as motor control.