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Cellular localization and laminar distribution of AMPA glutamate receptor subunits mRNAs and proteins in the rat cerebral cortex.
No full textPostnatal development of parvalbumin-immunoreactive amacrine cells in the rabbit retina
No full textIn the adult rabbit, rat and cat retina, parvalbumin PV. immunoreactivity is primarily localized to a population of narrow-field, bistratified amacrine cells, the AII amacrine cells–major interneurons of the rod pathway. This investigation examines the postnatal
development of PV immunoreactivity in order to better understand the ontogeny of the AII amacrine cell population and the formation of the rod pathway. Rabbit retinas at various postnatal ages were processed for immunohistochemistry using a monoclonal antibody directed
to PV and analyzed morphometrically. On the day of birth, PV immunoreactive cell bodies are numerous in the proximal inner nuclear
layer INL. in all retinal regions. These cells have a primary process directed towards the inner plexiform layer IPL.. At postnatal day PND. 2, a few faint immunoreactive processes are observed in the IPL. At PND 4, well-stained processes are observed to ramify mainly in the proximal IPL. At PND 6, strongly immunoreactive processes are present in both the distal and proximal IPL, and at PND 10 they
form a continuous, dense plexus in both levels of the IPL. By PND 10, the morphology of PV immunoreactive cells is similar to PV immunoreactive cells in adult retinas. The density of PV immunoreactive cells in the proximal INL increases from PND 2 to PND 5, then it gradually decreases to adult values, while the total number of PV immunoreactive cell bodies increases until PND 10. PV
immunoreactive amacrine cells at PND 2, as in the adult, are nonrandomly distributed across the retinal surface. These studies show that
PV immunoreactive amacrine cells have a developmental profile that is similar to several other amacrine cell types. This includes the elaboration of processes in the IPL during the first postnatal week and a mature appearance towards the end of the second week of life,
about the time of eye opening. These observations indicate that the AII amacrine cell may participate in the processing of visual information at eye opening
Cellular localization and laminar distribution of NMDAR1 mRNA in the rat cerebral cortex.
No full textNeurokinin 1 receptor expression in the rat retina
No full textTachykinin (TK) peptides influence neuronal activity in the inner retina of mammals. The
aim of this investigation was to determine the cellular localization of the neurokinin 1
receptor (NK1), whose preferred ligand is the TK peptide substance P (SP), in the rat retina.
These studies used a polyclonal antiserum directed to the C-terminus of rat NK1. The
majority of NK1-immunoreactive (IR) cells were located in the proximal inner nuclear layer
(INL), and very rarely they were found in the distal INL. Some small and large NK1-IR
somata were present in the ganglion cell layer. NK1-IR processes were densely distributed
across the inner plexiform layer (IPL) with a maximum density over lamina 2 of the IPL.
Immunoreactive processes also crossed the INL and ramified in the outer plexiform layer
where they formed a sparse meshwork. NK1-IR processes were rarely observed in the optic
nerve fiber layer. Double-label immunofluorescence studies with different histochemical
markers for bipolar cells indicated that NK1 immunoreactivity was not present in bipolar
cells. Together, these observations indicate that NK1 immunoreactivity is predominantly
expressed by amacrine, displaced amacrine, interplexiform, and some ganglion cells. Doublelabel
immunofluorescence experiments were also performed to characterize NK1-containing
amacrine cells. Sixty-one percent of the g-aminobutyric acid (GABA)-IR cells, 71% of the large
tyrosine hydroxylase (TH)-IR cells, and 100% of the small TH-IR cells contained NK1
immunoreactivity. In addition, most (91%) of the NK1-IR cells had GABA immunoreactivity.
In contrast, vasoactive intestinal polypeptide-, TK-, choline acetyltransferase-, and parvalbumin-
IR amacrine cells did not express NK1 immunoreactivity. Overall, the present findings
suggest that SP acts directly upon several cell populations, including GABA-containing
amacrine cells and ganglion cells, to influence visual information processing in the inner
retina
Distribution of preproenkephalin mRNA in the chicken and pigeon telencephalon
No full textBioassay and immunological studies have detected the presence of opioid peptides in the nervous system of representatives of all classes of vertebrates. The present study evaluates the expression and localization of preproenkephalin (PPE) mRNA to determine the sites of synthesis of the enkephalin peptides in the adult chicken and pigeon telencephalon using in situ hybridization histochemistry. We used a 500-base-pair chicken RNA probe corresponding to chicken PPE cDNA. In both the chicken and the pigeon telencephalon, the highest concentration of PPE mRNA-containing cells was observed in the lobus parolfactorius, paleostriatum augmentatum, nucleus accumbens, and septum. Distinct populations of labeled cells were also detected in the hyperstriatum accessorium, hippocampus, area parahippocampalis, nucleus of the diagonal band, cortex dorsolateralis, and cortex piriformis. Differences in PPE mRNA expression between chicken and pigeon were observed in several telencephalic regions. For instance, the bulbus olfactorius was heavily labeled in the pigeon, but was not labeled in the chicken, and numerous PPE mRNA-containing cells were present in the area parahippocampalis of pigeons but not of chickens. In contrast, in the hyperstriatum dorsale and hyperstriatum ventrale, numerous PPE mRNA-expressing cells were detected in the chicken but not in the pigeon. Overall, PPE mRNA-expressing cells were more numerous than enkephalin-immunoreactive cells described in previous studies. In addition, our results suggest that the general pattern of enkephalin expression in the avian telencephalon is similar to that found in other vertebrates. Finally, the results of the present study illustrate some differences in the pattern of PPE mRNA distribution between closely related species, indicating the existence of species-specific neurochemical pathways, which may influence and perhaps mediate different behaviors characteristics of these species
Etorphine increases the number of μ-opioid receptor-positive cells in the cerebral cortex
No full textDevelopmental expression of neurokinin-1 and neurokinin-3 receptors in the rat retina
No full textTachykinin (TK) peptides act on retinal neurons through neurokinin (NK) receptors. We examined the expression of neurokinin-1 (NK1; the substance P receptor), NK3 [the neurokinin B (NKB) receptor], and TK peptides in developing rat retinas. NK1 immunolabeling was found in newborn retinas in rare amacrine cells and in putative ganglion cells. At postnatal day 2 (PND 2), NK1 immunostaining was reduced greatly among ganglion cells, and it appeared in many amacrine cells and in fibers in the inner plexiform layer (IPL), with the highest density in laminae 1, 3, and 5. A similar pattern was found at PND 7. At PND 12, interplexiform NK1-immunoreactive (-IR) cells were detected, and NK1-IR fibers in the IPL were concentrated in lamina 2, similar to what was seen in adults. NK3 was expressed mainly by OFF-cone bipolar cells, and the developmental pattern of NK3 was compared with that of cone bipolar cells that were labeled with antibodies to recoverin. Immature recoverin-IR cone bipolar cells were seen at PND 2. NK3 immunolabeling was detected first in the outer plexiform layer and in sparse bipolar cell somata at PND 10, when recoverin-IR cone bipolar cells are nearly mature. By PND 15, both the NK3 immunostaining pattern and the recoverin immunostaining pattern were similar to the patterns seen in adults. TK immunoreactivity was present at PND 0 in amacrine cells and displaced amacrine cells. By PND 10, the morphologic maturation of TK-IR cells was complete. These findings indicate that, in early postnatal retinas, substance P may act on NK1 receptors, whereas NKB/NK3 interactions are unlikely, suggesting that there are different levels of importance for different TK peptides in the developing retina
Role of agonist-dependent receptor internalization in the regulation of mu opioid receptors.
No full textDifferential expression of two vesicular monoamine transporters
No full textSpecific transport proteins package classical neurotransmitters into vesicles so that their release can be regulated by neural activity. Previous studies have suggested that s single activity mediates the vesicular transport of monoamines in the adrenal gland, brain, and other tissues such as mast cells and platelets. However, molecular cloning has recently identified two vesicular transporters for monoamines. Although the predicted proteins are closely related in sequence, they show a range of differences in their physiologic and pharmacologic properties. To clarify further the biological significance of the observed functional differences, we have generated anti-peptide antibodies to the C-termini of the two transporters and used them to determine the distribution and localization of the proteins in the rat. We have detected expression of vesicular monoamine transporter 1 (VMAT1) in adrenal chromaffin cells but not in neural cells. Interestingly, some adrenal chromaffin cells also express VMAT2 but the amount of VMAT2 relative to VMAT1 appears much lower than in the bovine adrenal gland. In contrast, sympathetic ganglion cells express only VMAT2, as do enteric neurons and enterochromaffin-like cells of the stomach. Thus, although adrenal chromaffin cells, sympathetic end enteric neurons derive from the neural crest, they express different vesicular amine transporters. In the CNS, dopamine, norepinephrine, epinephrine, 5-HT, and histamine cell groups all express VMAT2. These findings are consistent with the functional characteristics of VMAT1 and VMAT2 and help to explain several classic pharmacological observations. VMAT2-immunoreactivity is generally stronger in cell bodies, proximal dendrites and axonal processes, indicating the potential for monoamine storage at each of these sites. Surprisingly, dopaminergic interneurons in the olfactory bulb show no detectable immunoreactivity for either VMAT1 or VMAT2
Neuronal, glial and epithelial localization of gamma-aminobutyric acid transporter 2, a high-affinity gamma-aminobutyric acid plasma membrane transporter, in the cerebral cortex and neighboring structures.
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