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Immunocytochemical development of the guinea pig retina.

The aim of the present study was to establish the neurochemical profile of amacrine and horizontal cells during ontogeny in the guinea pig, a precocial species where significant retinal development occurs prenatally as opposed to altricial species where development largely occurs postnatally. The expression of neurochemical markers of horizontal cells and specific amacrine cell populations was investigated from 20 days of gestation (dg, term approximately 67 dg) to adulthood. Amacrine cell populations were identified immunohistochemically using antibodies to gamma-amino-butyric acid, cholineacetyltransferase, calbindin, calretinin, neuronal nitric oxide synthetase and tyrosine hydroxylase; horizontal cells were labelled with calbindin. All markers were present at 30 dg and had attained their mature (adult) laminar distribution and expression by 60 dg. Horizontal cells appeared in their final location at 30 dg with amacrine cell populations appearing in their final locations by 45 dg. Thus, in the guinea pig retina, the amacrine and horizontal cell populations investigated in this study are fully mature prior to birth.

Amacrine Cells↗

Presbyacusis and calcium-binding protein immunoreactivity in the cochlear nucleus of BALB/c mice.

The BALB/c mouse is an established model for the early development of sensorineural hearing loss, and is homozygous for the Ahl allele (age-related hearing loss). The present study was designed to determine how auditory peripheral pathology influences calcium-binding protein immunoreactivity in the cochlear nucleus in aged BALB/c mice. To address this issue the loss of hair cells, spiral ganglion neurons (SGN), and neurons in the dorsal (DCN) and posteroventral (PVCN) cochlear nucleus of BALB/c mice at 1 and 24 months of age were quantified using CAST stereological methods. These values were then compared to the percent increase in immunopositive calcium-binding proteins in the cochlear nucleus. By 24 months of age there was a near complete loss of all outer hair cells (OHC). The inner hair cell (IHC) loss was near complete in the more apical and basal regions, while in the mid-regions approximately 50% were missing. The SGN in the apical and middle turns show a 20% loss (re: 1 month) and the basal turn up to 80% loss. A statistically significant decrease in the density of DCN and PVCN neurons (25%) was found at 24 months of age compared to the one month old animals. The percentage of parvalbumin and calretinin positive neurons in the DCN and the PVCN in relation to the density of Nissl stained neurons showed significant increases at 24 months compared to the 1 month old animals. We also determine the relationship between peripheral pathology and the percent increase in calcium-binding protein immunoreactivity. In the DCN, the percent increase of calretinin and parvalbumin was correlated to the loss of SGN, IHCs and OHCs. In the PVCN, parvalbumin was correlated to SGN, IHC, and OHC loss. The percent increase in calbindin immunoreactivity was not correlated to any peripheral pathology. The data here suggest a percent increase in calcium-binding protein immunoreactivity in the cochlea nucleus in the 24 month old mice may reflect an endogenous protective strategy that is designed to counteract calcium overload that is prominent during aging and degeneration. These results will be valuable for understanding the relationship among the peripheral and central auditory system in a model demonstrating a rapidly progressive presbyacusis.

Aging↗

Differential effects of aging on the distribution of calcium-binding proteins in a pretectal nucleus of the chicken brain.

The nucleus pretectalis (PT) of birds is an ovoid-shaped visuomotor cell group of the pretectum that receives tectal input and projects back to the optic tectum. We performed immunohistochemical single- and double-labeling to determine the distribution and abundance of neurons containing three calcium-binding proteins, parvalbumin (PV), calretinin (CR), and calbindin (CB), in the PT in chickens at three ages. We found that PV-positive and CR-positive cells co-localize and are largely found in the outer part of PT at all ages. The GluR4 subunit of the AMPA-type glutamate receptor was selectively localized to these neurons. CB-positive neurons, however, were largely absent from the PT in young and adult chickens. The abundance of PV-positive and CR-positive neurons in PT in old birds was indistinguishable from that in the younger birds, but CB-positive perikarya were 10-20-fold more common than in young birds, and were again mainly found in the outer part of PT. The overall abundance of neurons in PT was reduced to about 50% of its former abundance in the old birds, with this loss restricted to the central part of the nucleus. These data indicate that a cell loss process develops in PT as birds age, that parvalbuminergic and calretinergic neurons resist this process, and that this process is associated with increased expression of CB.

Aging↗

Postnatal development of calcium-binding proteins immunoreactivity (parvalbumin, calbindin, calretinin) in the human entorhinal cortex.

The entorhinal cortex is an essential component in the organization of the human hippocampal formation related to cortical activity. It transfers, neocortical information (ultimately distributed to the dentate gyrus and hippocampus) and receives most of the hippocampal output directed to neocortex. At birth, the human entorhinal cortex presents similar layer organization as in adults, although layer II (cell islands) and upper layer III have a protracted maturation. The presence of interneurons expressing calcium-binding proteins (parvalbumin, calbindin-D28K (calbindin) and calretinin) is well documented in the adult human entorhinal cortex. In many of them the calcium binding is co-localized with GABA. Parvalbumin-immunoreactive cells and fibers were virtually absent at birth, their presence increasing gradually in deep layer III, mostly in the lateral and caudal portions of the entorhinal cortex from the 5th month onwards. Calbindin immunoreactive cells and fibers were present at birth, mainly in layers II and upper III; mostly at rostral and lateral portions of the entorhinal cortex, increasing in number and extending to deep layers from the 5th month onwards. Calretinin immunoreactivity was present at birth, homogeneously distributed over layers I, II and upper V, throughout the entorhinal cortex. A substantial increase in the number of calretinin neurons in layer V was observed at the 5th month. The postnatal development of parvalbumin, calbindin and calretinin may have an important role in the functional maturation of the entorhinal cortex through the control of hippocampal, cortical and subcortical information.

Calbindin 1↗

Cyto- and chemoarchitecture of the dorsal thalamus of the monotreme Tachyglossus aculeatus, the short beaked echidna.

We have examined the cyto- and chemoarchitecture of the dorsal thalamus of the short beaked echidna (Tachyglossus aculeatus), using Nissl and myelin staining, immunoreactivity for parvalbumin, calbindin, calretinin and non-phosphorylated neurofilament protein (SMI-32 antibody), and histochemistry for acetylcholinesterase and NADPH diaphorase. Immunohistochemical methods revealed many nuclear boundaries, which were difficult to discern with Nissl staining. Parvalbumin immunoreactive somata were concentrated in the ventral posterior, reticular, posterior, lateral and medial geniculate nuclei, while parvalbumin immunoreactivity of the neuropil was present throughout all but the midline nuclei. Large numbers of calbindin immunoreactive somata were also found within the midline thalamic nuclei, and thalamic sensory relay nuclei. Immunoreactivity for calretinin was found in many small somata within the lateral geniculate "a" nucleus, with other labelled somata found in the lateral geniculate "b" nucleus, ventral posterior medial and ventral posterior lateral nuclei. Immunoreactivity with the SMI-32 antibody was largely confined to somata and neuropil within the thalamocortical relay nuclei (ventral posterior medial and lateral nuclei, lateral and medial geniculate nuclei and the posterior thalamic nucleus). In broad terms there were many similarities between the thalamus of this monotreme and that of eutheria (e.g. disposition of somatosensory thalamus, complementarity of parvalbumin and calbindin immunoreactive structures), but there were some unique features of the thalamus of the echidna. These include the relatively small size of the thalamic reticular nucleus and the preponderance of calbindin immunoreactive neurons over parvalbumin immunoreactive neurons in the ventral posterior nucleus.

Acetylcholinesterase↗

Cyto- and chemoarchitecture of the sensory trigeminal nuclei of the echidna, platypus and rat.

We have examined the cyto- and chemoarchitecture of the trigeminal nuclei of two monotremes using Nissl staining, enzyme reactivity for cytochrome oxidase, immunoreactivity for calcium binding proteins and non-phosphorylated neurofilament (SMI-32 antibody) and lectin histochemistry (Griffonia simplicifolia isolectin B4). The principal trigeminal nucleus and the oralis and interpolaris spinal trigeminal nuclei were substantially larger in the platypus than in either the echidna or rat, but the caudalis subnucleus was similar in size in both monotremes and the rat. The numerical density of Nissl stained neurons was higher in the principal, oralis and interpolaris nuclei of the platypus relative to the echidna, but similar to that in the rat. Neuropil immunoreactivity for parvalbumin was particularly intense in the principal trigeminal, oralis and interpolaris subnuclei of the platypus, but the numerical density of parvalbumin immunoreactive neurons was not particularly high in these nuclei of the platypus. Neuropil immunoreactivity for calbindin and calretinin was relatively weak in both monotremes, although calretinin immunoreactive somata made up a large proportion of neurons in the principal, oralis and interpolaris subnuclei of the echidna. Distribution of calretinin immunoreactivity and Griffonia simplicifolia B4 isolectin reactivity suggested that the caudalis subnucleus of the echidna does not have a clearly defined gelatinosus region. Our findings indicate that the trigeminal nuclei of the echidna do not appear to be highly specialized, but that the principal, oralis and interpolaris subnuclei of the platypus trigeminal complex are highly differentiated, presumably for processing of tactile and electrosensory information from the bill.

Animals↗

Glutathione deficit during development induces anomalies in the rat anterior cingulate GABAergic neurons: Relevance to schizophrenia.

A series of studies in schizophrenic patients report a decrease of glutathione (GSH) in prefrontal cortex (PFC) and cerebrospinal fluid, a decrease in mRNA levels for two GSH synthesizing enzymes and a deficit in parvalbumin (PV) expression in a subclass of GABA neurons in PFC. GSH is an important redox regulator, and its deficit could be responsible for cortical anomalies, particularly in regions rich in dopamine innervation. We tested in an animal model if redox imbalance (GSH deficit and excess extracellular dopamine) during postnatal development would affect PV-expressing neurons. Three populations of interneurons immunolabeled for calcium-binding proteins were analyzed quantitatively in 16-day-old rat brain sections. Treated rats showed specific reduction in parvalbumin immunoreactivity in the anterior cingulate cortex, but not for calbindin and calretinin. These results provide experimental evidence for the critical role of redox regulation in cortical development and validate this animal model used in schizophrenia research.

Animals↗

Age-related increases in calcium-binding protein immunoreactivity in the cochlear nucleus of hearing impaired C57BL/6J mice.

Aging C57BL/6J (C57) mice (1-30 months old), were used to study calcium-binding protein immunoreactivity (parvalbumin, calbindin and calretinin) in the cochlear nucleus. A quantitative stereological method, the optical fractionator was used to determine the total number of neurons, and the total number of immunostained neurons in the posteroventral- and dorsal cochlear nuclei (PVCN and DCN). A statistically significant age-related decrease of the total number of neurons was found in the PVCN and DCN using Nissl staining. In the DCN, an age-related increase in the total number of parvalbumin-positive neurons was found, while no changes in the total number of calbindin or calretinin positive neurons were demonstrated. In the PVCN, the total number of parvalbumin, calbindin, or calretinin positive neurons remained stable with increasing age. The percentage of parvalbumin, calbindin, and calretinin positive neurons significantly increased in the DCN, and the percentage of parvalbumin and calbindin-positive neurons increased in the PVCN. These findings imply that there is a relative up-regulation of calcium-binding proteins in neurons that had not previously expressed these proteins. This plastic response in the profoundly hearing impaired C57 mouse may be a survival strategy for cochlear nucleus neurons.

Adaptation, Physiological↗

The transcription factor Bhlhb4 is required for rod bipolar cell maturation.

Retinal bipolar cells are essential to the transmission of light information. Although bipolar cell dysfunction can result in blindness, little is known about the factors required for bipolar cell development and functional maturation. The basic helix-loop-helix (bHLH) transcription factor Bhlhb4 was found to be expressed in rod bipolar cells (RB). Electroretinograms (ERGs) in the adult Bhlhb4 knockout (Bhlhb4(-/-)) showed that the loss of Bhlhb4 resulted in disrupted rod signaling and profound retinal dysfunction resembling human congenital stationary night blindness (CSNB), characterized by the loss of the scotopic ERG b-wave. A depletion of inner nuclear layer (INL) cells in the adult Bhlhb4 knockout has been ascribed to the abolishment of the RB cell population during postnatal development. Other retinal cell populations including photoreceptors were unaltered. The timing of RB cell depletion in the Bhlhb4(-/-) mouse suggests that Bhlhb4 is essential for RB cell maturation.

Age Factors↗

Ptf1a, a bHLH transcriptional gene, defines GABAergic neuronal fates in cerebellum.

The molecular machinery governing glutamatergic-GABAergic neuronal subtype specification is unclear. Here we describe a cerebellar mutant, cerebelless, which lacks the entire cerebellar cortex in adults. The primary defect of the mutant brains was a specific inhibition of GABAergic neuron production from the cerebellar ventricular zone (VZ), resulting in secondary and complete loss of external germinal layer, pontine, and olivary nuclei during development. We identified the responsible gene, Ptf1a, whose expression was lost in the cerebellar VZ but was maintained in the pancreas in cerebelless. Lineage tracing revealed that two types of neural precursors exist in the cerebellar VZ: Ptf1a-expressing and -nonexpressing precursors, which generate GABAergic and glutamatergic neurons, respectively. Introduction of Ptf1a into glutamatergic neuron precursors in the dorsal telencephalon generated GABAergic neurons with representative morphological and migratory features. Our results suggest that Ptf1a is involved in driving neural precursors to differentiate into GABAergic neurons in the cerebellum.

Age Factors↗

The zinc finger transcription factor Sp8 regulates the generation and diversity of olfactory bulb interneurons.

The molecular mechanisms that regulate the production and diversity of olfactory bulb interneurons remain poorly understood. With the exception of the GABAergic/dopaminergic subtype in the glomerular layer, no information exists concerning the generation of the other subtypes. Here we show that the recently identified zinc finger transcription factor Sp8 is expressed in neurogenic regions, which give rise to olfactory bulb interneurons at embryonic and postnatal time points and remains expressed in the calretinin-expressing and GABAergic/nondopaminergic interneurons of the glomerular layer. Conditional inactivation of Sp8 in the embryonic ventral telencephalon reveals a requirement for the normal generation of these interneuron subtypes. Sp8 conditional mutants exhibit an increase in cell death within the lateral ganglionic eminence and rostral migratory stream. Moreover, mutant neuroblasts/interneurons are misspecified and display abnormal migration patterns in the olfactory bulb, indicating that Sp8 contributes to olfactory bulb interneuron diversity by regulating the survival, migration, and molecular specification of neuroblasts/interneurons.

Animals↗

Compartmentation of the reeler cerebellum: segregation and overlap of spinocerebellar and secondary vestibulocerebellar fibers and their target cells.

The cerebellum of the reeler mutant mouse has an abnormal organization; its single lobule is composed of a severely hypogranular cortex and a central cerebellar mass (CCM) consisting of Purkinje cell clusters intermixing with the cerebellar nuclei. As such the reeler represents an excellent model in which to examine the effect of the abnormal distribution of cerebellar cells on afferent-target relationships. To this effect we studied the organization of the spinocerebellar and secondary vestibulocerebellar afferent projections in homozygous reeler mice (rl/rl) using anterograde tracing techniques. Spinal cord injections resulted in labeled spinocerebellar mossy fiber rosettes in specific anterior and posterior regions of the cerebellar cortex. Some vestiges of parasagittal organization may be present in the anterior projection area. Within the CCM, labeled fibers appeared to terminate on distinct groups of Purkinje cells. Thus, the spinocerebellar mossy fibers seem to form both normal and heterologous synapses in the reeler cerebellum. Secondary vestibular injections resulted in both retrograde and anterograde labeling. Retrograde labeling was seen in clusters of Purkinje cells and cerebellar nuclear cells; anterograde labeling was distributed in the white matter and in specific regions of the anterior and posterior cortex of the cerebellum. The labeled spinocerebellar and secondary vestibulocerebellar afferents overlapped in the anterior region but in the posterior region the vestibulocerebellar termination area was ventral to the spinocerebellar area. An area devoid of labeled terminals was also observed ventral to the posterior secondary vestibulocerebellar termination field. Using calretinin immunostaining it was determined that this area contains unipolar brush cells, a cell type found primarily in the vestibulocerebellum of normal mice. Our data indicate that despite of the lack of known landmarks (fissures, lobules) the spinocerebellar and vestibulocerebellar afferent projections in the reeler cerebellum do not distribute randomly but have specific target regions, and the position of these regions, relative to each other, appears to be conserved. Two caveats to this were the finding of overlapping terminal fields of these afferents in the anterior region, and a posteroventral region that contains unipolar brush cells yet is devoid of secondary vestibulocerebellar afferents. The distribution of Purkinje cells and cerebellar nuclear cells is not random either; those that give rise to cerebellovestibular efferents form distinct groups within the central cerebellar mass.

Animals↗

Purkinje cell rhythmicity and synchronicity during modulation of fast cerebellar oscillation.

Fast (approximately 160 Hz) cerebellar oscillation has been recently described in different models of ataxic mice, such as mice lacking calcium-binding proteins and in a mouse model of Angelman syndrome. Among them, calretinin-calbindin double knockout mice constitute the best model for evaluating fast oscillations in vivo. The cerebellum of these mice may present long-lasting episodes of very strong and stable local field potential oscillation alternating with the normal non-oscillating state. Spontaneous firing of the Purkinje cells in wild type and double knockout mice largely differs. Indeed, the Purkinje cell firing of the oscillating mutant is characterized by an increased rate and rhythmicity and by the emergence of synchronicity along the parallel fiber axis. To better understand the driving role played by these different parameters on fast cerebellar oscillation, we simultaneously recorded Purkinje cells and local field potential during the induction of general anesthesia by ketamine or pentobarbitone. Both drugs significantly increased Purkinje cell rhythmicity in the absence of oscillation, but they did not lead to Purkinje cell synchronization or to the emergence of fast oscillation. During fast oscillation episodes, ketamine abolished Purkinje cell synchronicity and inhibited fast oscillation. In contrast, pentobarbitone facilitated fast oscillation, induced and increased Purkinje cell synchronicity. We propose that fast cerebellar oscillation is due to the synchronous rhythmic firing of Purkinje cell populations and is facilitated by positive feedback whereby the oscillating field further phase-locks recruited Purkinje cells onto the same rhythmic firing pattern.

Anesthetics, Dissociative↗

Sex-specific effects of chronic anabolic androgenic steroid treatment on GABA(A) receptor expression and function in adolescent mice.

Anabolic androgenic steroids are synthetic derivatives of testosterone designed for therapeutic uses, but now taken as drugs of abuse. Potential health risks associated with anabolic androgenic steroid abuse are believed to be higher in adolescents than in adults, but few studies have tested anabolic androgenic steroid effects in adolescent subjects or determined if effects of these steroids differ between females and males. We have studied GABA(A) receptor expression and function in the medial preoptic nucleus of mice chronically treated during adolescence with the anabolic androgenic steroid, 17alpha-methyltestosterone. Three-week treatment did not elicit significant differences the expression of alpha1, alpha2 or alpha5 subunit mRNAs in animals of either sex, although there was a trend toward decreases in all three subunit mRNAs in female mice, which was augmented and attained significance for the alpha2 subunit mRNA in females treated for six weeks. Immunocytochemical analysis revealed that treatment with 17alpha-methyltestosterone for 6 weeks also elicited a significant decrease in the number of alpha2-immunopositive neurons in female subjects. To test if anabolic androgenic steroid treatment also promoted changes in GABA(A) receptor function, spontaneous inhibitory synaptic currents were analyzed in adolescent animals treated for 3-4 weeks. This treatment regimen promoted a significant decrease in spontaneous inhibitory synaptic current frequency in female, but not male mice. Finally, anabolic androgenic steroid treatment was found to have no effect on the numbers of interneurons within the medial preoptic nucleus, as assessed by immunoreactivity for calcium binding proteins, suggesting that the decrease in the frequency of spontaneous inhibitory synaptic currents in female mice does not arise from an anabolic androgenic steroid-induced loss of interneurons. Taken together, our results indicate that chronic exposure to 17alpha-methyltestosterone elicits significant changes in GABAergic transmission in the medial preoptic nucleus of female, but not male, mice effectively enhancing the sexually dimorphic nature of GABAergic transmission in a forebrain region crucial for the expression of aggression and sexual behaviors.

Anabolic Agents↗

Selective deficits in prefrontal cortical GABAergic neurons in schizophrenia defined by the presence of calcium-binding proteins.

BACKGROUND: Postmortem studies have provided evidence for abnormalities of the gamma-aminobutyric acid (GABA)-ergic system in schizophrenia, including deficits of GABA-containing interneurons. The calcium-binding proteins parvalbumin, calbindin, and calretinin can be used as markers for specific subpopulations of cortical GABAergic interneurons. METHODS: Following our previous observation of a reduction in the density of parvalbumin- but not calretinin-immunoreactive cells in the prefrontal cortex (Brodmann area 10) in schizophrenia, we have quantified the laminar density of neurons immunoreactive for the calcium-binding proteins parvalbumin, calbindin, and calretinin in a further prefrontal cortical region (Brodmann area 9) in patients with schizophrenia, bipolar disorder, major depression, and in matched control subjects (each group n = 15). RESULTS: Initial statistical analysis revealed reductions in the total cortical density of parvalbumin- and calbindin- but not calretinin-immunoreactive neurons in schizophrenia relative to control subjects. Further analysis comparing individual laminar densities between groups indicated that, following correction for multiple comparisons, only a reduction in calbindin-immunoreactive neurons in cortical layer II in the schizophrenic group attained statistical significance. CONCLUSIONS: These findings suggest that deficits of specific GABAergic neurons, defined by the presence of calcium-binding proteins, are present in schizophrenia. Trends toward similar reductions are observed in bipolar disorder.

Adult↗

The core-shell dichotomy of nucleus accumbens in the rhesus monkey as revealed by double-immunofluorescence and morphology of cholinergic interneurons.

Double-immunolabelling experiments for the combinations, calretinin (CR)-calbindin, CR-tyrosine hydroxylase (TH) and calbindin-TH, were performed in rhesus monkeys to compare the chemical organization of the nucleus accumbens (ACC) in primates and rodents. Additionally, the soma sizes and numbers of primary dendrites of cholinergic neurons in the subregions of ACC were compared with those of caudate-putamen. Our findings subserve the shell-core concept also in the primate ACC, as like in the rat, CR immunoreactivity (-ir) due to intense neuropil labelling is very strong in the shell of rhesus monkey, but poor in the core. The staining intensity of this marker decreases in dorsoventral direction. An almost complementary pattern was noted in sections of the monkey ACC immunostained for both calbindin and TH. The cholinergic interneurons of the nucleus caudatus-putamen are clearly distinguished from those of the ACC and insula Calleja magna by their much bigger soma sizes and higher numbers of primary dendrites. Cholinergic neurons of the shell were found to be slightly, but significantly, larger than those of the core that also subserves subdivision of the primate ACC into shell and core. A low proportion of tyrosine-hydroxylase-immunostained cells, already previously described below the rostral ACC, co-expressed CR but not calbindin. A CR-immunoreactive neuronal population, intermingled with these cells, extends as a stripe medially to the ACC along the septal part of corpus callosum into the lateral septal area. The presumed origin of CR-immunoreactive fibres in the shell of ACC is discussed.

Acetylcholine↗

Calretinin-containing axons and neurons are resistant to an intrastriatal 6-hydroxydopamine lesion.

Relative preservation of dopaminergic axons in patches and a subcallosal layer was observed in the dorsal, lateral and caudal striatum 4 weeks after intrastriatal injection of 6-hydroxydopamine (6-OHDA), a neurotoxin selective for catecholaminergic neurons. Since calcium binding proteins are reported to provide neuroprotective influence in neurons, differences in the distribution of the calcium binding proteins might be related to the different vulnerabilities of dopaminergic neurons and axons to neurotoxins. To address this possibility, we characterized patches of relatively dense tyrosine hydroxylase-immunoreactive (TH-IR) axons in intrastriatal 6-OHDA lesioned rats, focusing on two calcium binding proteins, calbindin (CB) and calretinin (CR). The patches and subcallosal layer of preserved dopaminergic axons in the striatum of rats lesioned with 6-OHDA contained CR, a 31-kDa calcium-binding protein, but interestingly not CB. Dopaminergic neurons containing CR in the substantia nigra pars compacta (SNpc) were relatively spared compared to those that did not contain CR. Taken together, our data indicate that dopaminergic axons and neurons containing CR in the nigrostriatal pathway are more resistant to 6-OHDA lesion than those that do not contain CR.

Animals↗

Calretinin co-localizes with the NMDA receptor subunit NR1 in cholinergic amacrine cells of the rat retina.

Immunohistochemistry was used to verify whether choline-acetiltransferase colocalizes with calcium-binding proteins and NMDA receptor subunit NR1 in the rat retina. Whereas calbindin and parvalbumin were not observed in cholinergic amacrine cells, calretinin and NR1 were very frequently colocalized with ChAT. Calretinin/NR1-positive cells were also shown, suggesting that calretinin in cholinergic cells of the rat may be related to the buffering of excess intracellular calcium generated by activation of NMDA receptors.

Acetylcholine↗