Distribution Of GABA-like Immunoreactivity Research Articles

Co-localization of glycine and gaba immunoreactivity in interneurons in Macaca monkey cerebellar cortex

Previous work demonstrates that the cerebellum uses glycine as a fast inhibitory neurotransmitter [Ottersen OP, Davanger S, Storm-Mathisen J (1987) Glycine-like immunoreactivity in the cerebellum of rat and Senegalese baboon, Papio papio: a comparison with the distribution of GABA-like immunoreactivity and with [3H]glycine and [3H]GABA uptake. Exp Brain Res 66(1):211–221; Ottersen OP, Storm-Mathisen J, Somogyi P (1988) Colocalization of glycine-like and GABA-like immunoreactivities in Golgi cell terminals in the rat cerebellum: a postembedding light and electron microscopic study. Brain Res 450(1–2):342–353; Dieudonne S (1995) Glycinergic synaptic currents in Golgi cells of the rat cerebellum. Proc Natl Acad Sci U S A 92:1441–1445; Dumoulin A, Triller A, Dieudonne S (2001) IPSC kinetics at identified GABAergic and mixed GABAergic and glycinergic synapses onto cerebellar Golgi cells. J Neurosci 21(16):6045–6057; Dugue GP, Dumoulin A, Triller A, Dieudonne S (2005) Target-dependent use of coreleased inhibitory transmitters at central synapses. J Neurosci 25(28):6490–6498; Zeilhofer HU, Studler B, Arabadzisz D, Schweizer C, Ahmadi S, Layh B, Bosl MR, Fritschy JM (2005) Glycinergic neurons expressing enhanced green fluorescent protein in bacterial artificial chromosome transgenic mice. J Comp Neurol 482(2):123–141]. In the rat cerebellum glycine is not released by itself but is released together with GABA by Lugaro cells onto Golgi cells [Dumoulin A, Triller A, Dieudonne S (2001) IPSC kinetics at identified GABAergic and mixed GABAergic and glycinergic synapses onto cerebellar Golgi cells. J Neurosci 21(16):6045–6057] and by Golgi cells onto unipolar brush and granule cells [Dugue GP, Dumoulin A, Triller A, Dieudonne S (2005) Target-dependent use of coreleased inhibitory transmitters at central synapses. J Neurosci 25(28):6490–6498]. Here we report, from immunolabeling evidence in Macaca cerebellum, that interneurons in the granular cell layer are glycine+ at a density of 120 cells/linear mm. Their morphology indicates that they include Golgi and Lugaro cell types with the majority containing both glycine and GABA or glutamic acid decarboxylase. These data are consistent with the proposal that, as in the rat cerebellum, these granular cell layer interneurons corelease glycine and GABA in the primate cerebellum. The patterns of labeling for glycine and GABA within Golgi and Lugaro cells also indicate that there are biochemical sub-types which are morphologically similar.Further, we find that glycine, GABA and glutamic acid decarboxylase identified candelabrum cells adjacent to the Purkinje cells which is the first time that this interneuron has been reported in primate cerebellar cortex. We propose that candelabrum cells, like the majority of Golgi and Lugaro cells, release both glycine and GABA.

Ultrastructure and immunocytochemical distribution of GABA in layer III of the rat medial entorhinal cortex following aminooxyacetic acid-induced seizures.

Layer III of the entorhinal cortex (EC) is lesioned in patients with temporal lobe epilepsy (TLE). A similar neuropathology is also present in different animal models of TLE. For example, injection of the "indirect" excitotoxin aminooxyacetic acid (AOAA) into the EC of rats causes behavioral seizures and preferential loss of neurons in layer III of the medial EC. The animals also develop hyperexcitability of the EC and the hippocampal region CA1. To further explore the neuropathological changes within the EC, the ultrastructure and distribution of GABA-like immunoreactivity were assessed in layer III, 28 days after an intraentorhinal AOAA injection. At this time point, light microscopic preparations revealed that a large proportion of pyramidal (putative excitatory) neurons in layer III of the medial EC had degenerated, whereas GABA-immunoreactive neurons had survived. In immunogold-labeled ultrathin sections, the lesioned neuropil was found to contain morphologically intact GABA-containing neurons and nerve terminals. Pathologically swollen dendrites and electron-dense neuronal profiles were present in the lesioned sector as well. The majority of the electron-dense profiles was identified as degenerating dendritic spines that were closely apposed to strongly glutamate-immunopositive axon terminals. Thus, the entorhinal chemoarchitecture is dramatically altered following an episode of AOAA-induced epileptic seizures. One possible consequence of this pathology is a reduced "drive" of the surviving layer III GABA neurons, which in turn may cause hyperexcitability of the EC and the hippocampus. These findings may be of relevance for the genesis and spread of temporal lobe seizures.

Distribution of GABA-like immunoreactivity in the song system of the zebra finch

GABA-like immunoreactivity (GABA-LIR) was mapped in the male and female zebra finch song system using a polyclonal antibody to GABA. GABA-LIR was found throughout the song system in neurons and neuropil of the robust nucleus of the archistriatum (RA), the higher vocal center (HVC), Area X, the magnocellular nucleus of the neostriatum (MAN), and the dorsomedial portion of the nucleus intercollicularis (DM of ICo). Puncta present in the lateral division of MAN (1MAN) may be local interneurons since the only known afferents of 1MAN are from the dorsolateral nucleus of the anterior thalamus (DLM), which did not appear to have any cell bodies with GABA-LIR. Distinct and dense puncta with GABA-LIR were present in DLM, and may be projections from Area X/lobus parolfactorius (LPO). Dramatic sex differences in GABA-LIR distribution were found. Females did not appear to have any GABA-LIR above background in either RA of HVC. Females also did not appear to have a distinct Area X, although they did have many small, lightly staining cell bodies in the corresponding LPO. The distribution of GABA-LIR and sex differences in its distribution suggests that GABAergic neurons may play a role in the acquisition and/or production of song in the zebra finch.

Distribution of GABA-like immunoreactivity in the octopus brain

This paper presents the first evidence that some neurons in the octopus CNS contain δ-amino butyric acid (GABA). Using conventional immunohistochemical methods with appropriate controls, we obtained positive staining with an antibody to GABA in fibres in the neuropil of many lobes of the brain of the northern octopus Eledone cirrhosa. In several lobes cell bodies were also stained. Staining was not uniformly distributed in the brain nor within a particular lobe: some regions stained strongly, others not at all. These findings suggest that GABA should be added to the already long list of putative neurotransmitters in the cephalopod CNS.

Distribution of GABA-like immunoreactivity during post-metamorphic development and regeneration of the central nervous system in the ascidian Ciona intestinalis

During regeneration of the neural ganglion in Ciona intestinalis, the pattern of reappearance of some peptidergic cells is similar to the ontogenetic patterns exhibited by these cell types during normal post-metamorphic development. Using a specific antiserum to gamma-aminobutyric acid (GABA), we describe here the appearance of GABA-ergic cells in Ciona during both post-metamorphic development and regeneration of the neural ganglion following total ablation. Post-metamorphic animals were divided into the categories: 1, 3–5, 6–10, 11–15 and 23–27 mm in body length. Regeneration was monitored at 12, 15, 18, 21, 28 and 56 days post ablation. The first appearance of GABA-like immunoreactive cells during normal development were at the 3 to 5-mm stage where they were seen as discrete cells, without processes, evenly distributed in the cortical region throughout the ganglion. Fibres were first seen at the 6 to 10-mm stage. As development proceeded, GABA-like immunoreactive cells became more concentrated near the nerve root exits and along the dorsal rind of the ganglion. In regenerating ganglia, GABA was first detected at 18–21 days post ablation, in cells that lacked any obvious processes and that were distributed in all regions of the ganglion. At 28 days post ablation, processes could be detected in the neuropile, and after 56 days GABA cells were found predominantly in the same regions as in the normally developing adult ganglion. Although the overall pattern reflects that in a normal adult, a few differences were detectable. For example, rather more GABAergic cells were concentrated ventrally in the ganglion close to the neural gland.

Presumptive GABAergic centrifugal input to the lamprey retina: a double-labeling study with axonal tracing and GABA immunocytochemistry

The distribution of GABA-like immunoreactivity (GABA-LI) was performed in the lamprey retinopetal system which was previously identified by either anterograde or retrograde axonal tracing methods. This study was carried out at the ultrastructural level for the retina and under both the light and electron microscope for the mesencephalic retinopetal centers (M5 and RMA). The GABA-LI was distributed in about 40% of anterogradely HRP-labeled axon terminals in the inner retina. These made synaptic contacts upon either HRP-labeled ganglion cell dendrites or mostly on GABA-LI or on immunonegative amacrine cell dendrites and somata. The other immunonegative HRP-labeled axon terminals also established synaptic contacts on amacrine cell dendrites and somata. The mesencephalic retinopetal neurons, retrogradely labeled with HRP or [ 3H]proline, were GABA-LI in 65% of M5 somata and only in 15% of RMA neurons. M5 and RMA retinopetal neurons and dendrites, either GABA-LI or immunonegative, were contacted: (1) asymmetrically by HRP-labeled or unlabeled axon terminals containing rounded synaptic vesicles, always immunonegative and (2) symmetrically by HRP-unlabeled axon terminals containing pleiomorphic synaptic vesicles, which were either GABA-LI or immunonegative. The role of GABA as a putative neurotransmitter in the centrifugal visual system is discussed.

Quantitative analysis of the ultrastructural distribution of GABA-like immunoreactivity in the intermediate and medial part of hyperstriatum ventrale of chick

The intermediate and medial part of the hyperstriatum ventrale of the chick telencephalon plays a crucial role in the learning processes of imprinting. The distribution within the intermediate and medial part of the hyperstriatum ventrale of the neurotransmitter gamma-amino butyric acid was studied with light and electron microscopy using an antibody against this amino acid. The antibody labelled 18.4% of neuronal somata. GABA-labelled terminals made symmetrical synapses onto somata and dendrites of labelled and unlabelled neurons. Labelled somata received about three times as many synaptic boutons as unlabelled somata. Approximately 21% of synaptic terminals on labelled somata were themselves labelled; unlabelled somata received a higher proportion (37.6%) of such terminals. Most labelled terminals synapsing with dendrites were confined to the shafts; very few labelled terminals contributed to axospinous synapses. Synaptic contacts made on dendritic shafts by labelled boutons were intermingled with symmetrical and asymmetrical contacts from non-immunoreactive terminals. The proportion of labelled terminals received by labelled dendrites (33.1%) was approximately twice that received by unlabelled dendrites (15.9%). Labelled neurons therefore received a higher proportion of labelled terminals on their dendrites and a lower proportion on their somata compared with unlabelled neurons. No immunoreactivity was seen in glial cells or ependyma.

GABA‐like immunoreactivity in the macaque monkey retina: A light and electron microscopic study

The distribution of GABA-like immunoreactivity in the macaque monkey retina was studied by using postembedding techniques on semithin and ultrathin sections. At the light microscopic level, both inner and outer plexiform layers showed strong GABA-like immunoreactivity in the central retina. All the horizontal cells, some bipolar cells, 30-40% of amacrine cells, occasional interplexiform cells, and practically all displaced amacrine cells were labeled. In the peripheral retina (beyond 5 mm eccentricity), the outer plexiform layer and the horizontal cells were not labeled, but all other cell types showed the same labeling pattern as in the central retina. Synapses of the inner plexiform layer involving a pre- or postsynaptic GABA-labeled process were studied electron microscopically. Synapses involving a GABA-labeled presynaptic amacrine cell process made up 80% of the synapses observed. These GABA-labeled amacrine processes synapsed onto amacrine, bipolar, and ganglion cell processes as well as onto amacrine and ganglion cell bodies. Synapses involving a postsynaptic GABA-labeled process made up 20% of the synapses studied. The GABA-like immunoreactive processes were postsynaptic to bipolar cells at the dyads and to amacrine cells at conventional synapses.

Distribution of GABA-like immunoreactivity in myenteric plexus of carp, frog and chicken

The distribution of GABA-like immunoreactivity was studied by means of indirect immunocytochemical methods in some lower vertebrate species (carp, frog, chicken). An immunoreactive network was revealed in the myenteric plexus of the alimentary canal of carp. GABA-positive nerve cells were attached closely to the fibres in the stomach. In other gut regions immunostained neurons were less frequent. Immunoreactive fibres often formed baskets on the surfaces of immunonegative neurons along the whole length of the alimentary canal. The number of immunopositive nerve fibres and pericellular baskets seemed to be lower in the mid- and hingut than in the foregut region. A similar distribution of GABA-immunoreactivity was revealed in the frog myenteric plexus. The ganglionated foregut region possessed a relatively dense GABAergic innervation. This part of the gut contained immunostained nerve cells and fibres, while the mid- and hindgut possessed only a scanty fibre system. Chicken exhibited an extensive immunoreactive plexus for GABA, although the GABA-stained perikarya were restricted mainly to the duodenum. Further regions of the small intestine were poor in immunoreactive cell bodies, which suggests a segmental origin and arrangement of GABAergic innervation within the plexus. In all three species studied, GABA-positive fibres run into the circular muscle layer. The varicosity suggests their influence on the movement of the smooth muscles through modifying the transmitter release of neighbouring terminals.

Ontogeny of glutamate decarboxylase and ?-aminobutyric acid immunoreactivities in the rat cochlea

gamma-Aminobutyric acid (GABA)-ergic efferent nerve fibers were studied during the postnatal development of the rat cochlea, using light microscopic immunocytochemical techniques. Antibodies against GABA and its synthesizing enzyme, glutamate decarboxylase (GAD), were used. Immunoreactivity to GAD is already present at birth (postnatal day 1) and could be found below the inner hair cells of the basal turn. Immunoreactivity progressively extends toward the apical turn until day 3. GAD-like immunoreactivity appears under the outer hair cells on postnatal day 15 and is only found in the upper part of the second turn and in the apical turn. The distribution of GABA-like immunoreactivity closely corresponds to that observed with the anti-glutamate decarboxylase antibody. However, the GABA-like immunoreactivity appears about 1-2 days after GAD-like immunoreactivity. At the beginning of the 3rd postnatal week, an adult pattern of GABA- and GAD-like immunoreactivity is established. These results suggest that GABA, which appears under the inner hair cells largely before the onset of hearing, may play a neurotrophic function during cochlear maturation and participate in the regulation of the first cochlear potentials as soon as they appear.

Localization of GABA-like immunoreactivity in the ectostriatum of domestic chicks: GABA immunocytochemistry combined with Golgi impregnation.

The distribution of GABA-like immunoreactivity (GABA-LI) in the ectostriatal core (Ec) of domestic chicks (one to two days old) was investigated using (1) preembedding GABA immunocytochemistry and (2) Golgi impregnation and gold-toning combined with postembedding GABA immunocytochemistry. Two major classes of neurons which display GABA-LI were identified in chick Ec. Firstly, large GABA immunopositive cells which comprise at least two further subtypes: an ovoid or polygonal form of 14-18 microns diameter with no apparent polarity of dendrites and a smaller cell (10-14 microns) with ovoid or basket-shaped soma and often more polarized dendritic ramification. In both subtypes the dendritic surface is smooth or sparsely spiny. Secondly, a small GABA immunopositive cell which is characterized by a round cell body of 5-8 microns diameter and thin and sparsely ramifying dendrites of smooth surface or with irregular protrusions. Based upon comprehensive descriptions of ectostriatal cytoarchitectonics (Tömböl et al., 1988c), and synaptology (Watanabe et al., 1985), we argue that the GABA-immunopositive cell types of chick Ec are likely to represent inhibitory interneurons comparable with GABAergic inhibitory cell types described in mammalian visual cortex.

Distribution of GABA immunoreactivity in the cat retina: A light- and electron-microscopic study

The distribution of GABA-like immunoreactivity in the cat retina was studied through the use of preembedding immunocytochemistry for light microscopy and by postembedding immunogold techniques for electron microscopy. Staining was observed in both inner and outer plexiform layers. Approximately 30% of the somata in the amacrine portion of the inner nuclear layer were immunoreactive and included amacrine and interplexiform cells. Horizontal cells and a subpopulation of cone bipolar cells were also stained. In the ganglion cell layer, staining was observed in both small- and medium-sized neurons. GABA-labeled amacrine cells were presynaptic to somata of amacrine cells and to dendrites of amacrine, bipolar, and ganglion cells. Bipolar cells were a major target, receiving more than 60% of all labeled synapses in the inner plexiform layer. Many of these contacts were reciprocal synapses. These findings support a major role for GABA-labeled amacrines in providing feedback inhibition to bipolar cells in the inner retina.

Parvalbumin immunoreactivity in the reticular thalamic nucleus of developing rats.

Developmental changes in the distribution of parvalbumin immunoreactivity in the rat reticular thalamic nucleus from embryonic day 18 to adult were studied using immunohistochemistry. Neurons containing parvalbumin immunoreactivity in their cell somata were first detected at embryonic day 18. By embryonic day 20, many cells extended parvalbumin-positive fibers into the ventral thalamic nucleus. During development of the ventral thalamic nucleus, these fibers increased in number and thickness and ran in various directions. By postnatal day 16, these fibers became thinner and less well-stained. Neurons in the reticular thalamic nucleus extended their parvalbumin-positive axons into other nuclei of the thalamus, but in these other nuclei, parvalbumin-positive terminal and fibers developed primarily postnatally. In the reticular thalamic nucleus, the distribution of GABA-like immunoreactivity was very similar to that of parvalbumin at embryonic day 20 with cells extending fibers which contained immunoreactivity for GABA into the ventral thalamic nucleus. Thus parvalbumin immunoreactivity appears in the neurons of the reticular thalamic nucleus early in development of this nucleus, first in cell somata of neurons, then in their axons and dendrites. Apart from the ventral thalamic nucleus, the innervation by parvalbumin containing neurons in the reticular thalamic nucleus of the rest of the thalamus, showed a variable developmental pattern with different nuclei being innervated at different times, presumably reflecting the separate development of individual thalamic nuclei.

The effects of gabaculine in vivo on the distribution of GABA-like immunoreactivity in the rat retina

γ-Aminobutyric acid (GABA) is an inhibitory transmitter found in the retinae of mammals largely within certain amacrine cells. In previous studies from this laboratory, subcutaneous administration to rats of gabaculine, an enzyme-activated irreversible inhibitor of γ-aminobutyric acid (GABA)-transaminase, produced large, rapid and long-lasting increases in levels of retinal GABA. We employed immunocytochemistry to determine whether such changes in the levels of retinal GABA are accompanied by changes in the cellular distribution of GABA. Using a recently developed antiserum to a GABA-protein conjugate, and the peroxidase-antiperoxidase method, we examined retinae from control rats and from rats 2 or 8 h after administration of 10mgg/kg gabaculine. From previous work, retinal levels of GABA were respectively elevated 3- or 6-fold at those postgabaculine times. In the present study, marked changes in the distribution of GABA-like immunoreactivity (GABA-LIR) were apparent by 2 h after injection of gabaculine, and were more striking at 8 h postgabaculine. The pattern of staining for GABA-LIR strongly suggested that much of the GABA in gabaculine-treated retinae was within Mu¨ller glial cells. That observation provides evidence for the importance of those cells in the uptake and degradation of GABA after its release from retinal neurons.

Distribution of GABA-like immunoreactivity in the pigeon brain

The distribution of GABA-like immunoreactivity in glutaraldehyde-fixed pigeon brains was studied by means of a monoclonal antibody. GABA-like immunoreactivity was observed in neuronal perikarya of different sizes as well as in neuropil and in certain fiber tracts. Certain staining patterns indicated the existence of several GABAergic projection systems in the pigeon brain. Indeed, a high density of immunostained perikarya and a low density of labeled terminal-like elements was the prominent pattern in the nuclei subpretectalis and posteroventralis, while an absence of perikaryal GABA-like immunoreactivity and accumulations of immunoreactive dots were observed in the isthmo-optic nucleus, amongst others. In the optic tectum, stained cell bodies with radially oriented processes in layer IIi (10) and with horizontally oriented processes in layer IId (5) were seen and were reminiscent of autoradiographic labeling patterns obtained previously following tectal injection of tritiated GABA. In the cerebellum, GABA-like immunoreactivity involved all types of neurons with the exception of granule cells. Purkinje cells showed regionally different intensities of immunostaining. In addition, in folium X no stained basket-like elements were observed. Although there is no evidence as yet about the function of GABA in most of the structures, the present results indicate an important role for this neurotransmitter in the pigeon brain.

The distribution of GABA-like immunoreactivity in relation to ganglion structure in the abdominal nerve cord of the locust (Schistocerca gregaria)

An antiserum raised against GABA was used to stain the abdominal nervous system of the locust. To interpret the results, however, it was first necessary to describe the structure of the free abdominal and terminal ganglia. This was done on the basis of ethyl-gallate staining. The free abdominal ganglia are similar in structure to the abdominal neuromeres of the metathoracic ganglia. The terminal ganglion is composed of four neuromeres (representing ganglia 8–11), but only three can be distinguished in the adult on morphological grounds. The eighth neuromere resembles the free ganglia, but the ninth lacks DCI (dorsal commissure I) and the ‘T’ tracts. In the tenth, only DCII and III are recognisable of the commissures, but two more posterior ones of uncertain homology are also present. Immunocytochemistry reveals three populations of somata in each abdominal ganglion. Of these only one, the medial posterior group, is found in the thoracic ganglia. DCIV and the supra-median commissure are composed of stained neurites, DCII and V contain both unstained neurites and DCI, III and VI are unstained. With the exception of the median ventral tract, all the longitudinal tracts contain some stained axons.

The distribution of GABA-like immunoreactivity in the thoracic nervous system of the locust Schistocerca gregaria

An antiserum raised against gamma aminobuyric acid (GABA) was used to stain the thoracic nervous system of the locust. It stained both neuronal somata and processes within the neuropile. Among the stained somata, those of the three pairs of common inhibitory motor neurones could be identified in each of the three thoracic ganglia. In the pro- and mesothoracic ganglia five discrete groups of somata are stained, four ventral and one dorsal. In the metathoracic neuromere, an additional second dorsal group can be identified. In the abdominal neuromeres of the metathoracic ganglion both dorsal and ventral somata are stained but the latter cannot be divided into discrete populations. In each ganglion, dorsal commissures (DC) IV and V are composed of stained neurites, DCVII, the supramedian commissure, the perpendicular tract, and all the longitudinal tracts contain both stained and unstained neurites. DCI, II, III and VI, the ‘T’ and ‘I’ tracts are unstained. An abundance of GABA-like immunoreactive processes is found throughout the neuropile except for the anterior ventral association centre where stained processes are sparser. Some of the stained cell groups contain neurones that have been studied physiologically. The function of these neurones is discussed.

Distribution of GABA-like immunoreactivity in the brain of the honeybee.

The distribution of GABA-like immunoreactivity in the brain of the honeybee was investigated with antisera generated against GABA protein conjugates. The binding of the antisera in paraffin serial sections was studied with the peroxidase-antiperoxidase method. GABA-like immunoreactive fibers appeared in all main neuropile areas. The staining of the optic lobes showed pronounced stratification. The receptor cells of compound eyes, ocelli, and antennae were not labelled. Several prominent fiber tracts showed GABA-like immunoreactivity, whereas other tracts were devoid of staining. There are no major immunoreactive commissures linking the two brain hemispheres with the exception of small commissures that bridge short distances between the beta-lobes and the antennal lobes. Several fibers in the cervical connective were also labelled; some of those may descend from the suboesophageal ganglion to the thoracic ganglia. The dense reactivity seen in the optic and antennal neuropiles implies that GABA is more important in mediating local rather than more distant neural interactions.