Dopamine Immunoreactivity Research Articles

Distribution of dopamine immunoreactivity in the forebrain and midbrain of the snake Python regius: a study with antibodies against dopamine.

The distribution of dopamine (DA) immunoreactivity in the forebrain and midbrain of the ball python, Python regius, was studied by using recently developed antibodies against DA. In order to determine general and species-specific features of the DA system in reptiles, we have selected the ball python as a representative of a reptilian radiation that hitherto has not been the subject of (immuno)histochemical studies. Dopamine-containing cell bodies were found around the glomeruli and in the external plexiform layer of both the main and accessory olfactory bulb, but not in the telencephalon proper. In the diencephalon, DA cells were observed in several parts of the periventricular hypothalamic nucleus, in the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area, the magnocellular ventrolateral thalamic nucleus, and the pretectal posterodorsal nucleus. In the midbrain, DA cells were found in the ventral tegmental area, the substantia nigra, and the presumed reptilian homologue of the mammalian A8 cell group. Dopaminergic fibers and varicosities were observed throughout the whole brain, particularly in the telencephalon and diencephalon. The nucleus accumbens, striatum, olfactory tubercle, and nucleus of the accessory olfactory tract appear to have the most dense innervation, but the lateral septal nucleus, the dorsal ventricular ridge, and the nucleus sphericus also show numerous DA-containing fibers and varicosities. Except for the lateral cortex, cortical areas are not densely innervated by DA fibers. The DA system of the snake Python regius shares many features with that of lizards and turtles as determined with the same antibodies. The taxonomically close relationship between lizards and snakes, which together constitute the Squamata, is reflected in a similar distribution of DA fibers and varicosities to the dorsal ventricular ridge and the lateral cortex, and in the limited number of CSF-contacting DA neurons in the hypothalamus.

Immunoreactive dopamine beta-hydroxylase in neuronal groups in the goldfish brain.

Dopamine beta-hydroxylase immunoreactivity is visualized by immunocytochemical techniques for the first time in brainstem neurons of a teleost, the goldfish, Carassius auratus. Three anatomically separate populations of immunoreactive cells are elucidated: one group of moderately stained cells is identified in the isthmal tegmentum; a second group forms a continuous column of densely stained cells, lateral or dorsolateral to the medial longitudinal fasciculus from the midmedulla to the medullospinal transition zone, and a third group of densely stained cells is located dorsomedially in the postobecular region of the medulla. The location of these dopamine-beta-hydroxylase-immunoreactive neurons is similar to that in mammalian brains, i.e. in the locus coeruleus, lateral medullary tegmentum and area postrema. The presence of norepinephrine-synthesizing neurons in the above-listed brainstem regions of the goldfish provides further evidence for homologizing these nuclei to the same-named regions in mammalian brains.

Immunocytochemical analysis of the dopamine system in the forebrain and midbrain of Raja radiata: evidence for a substantia nigra and ventral tegmental area in cartilaginous fish.

The distribution of dopamine-containing cell somata and fibers in the forebrain and midbrain of a cartilaginous fish, Raja radiata, was investigated by means of antibodies directed against dopamine. Many small dopamine immunoreactive neurons are distributed throughout the telencephalon, including the olfactory bulbs. Within the diencephalon and particularly in the hypothalamus, i.e., in the nucleus preopticus, nucleus suprachiasmaticus, the paraventricular organ, lateral hypothalamic area, recessus mamillaris, and nucleus tuberculi posterioris, numerous cell somata stain for dopamine. In the mesencephalon, two distinct cell masses are found, which on the basis of their immunoreactivity for dopamine and their location, may be homologous to the substantia nigra and ventral tegmental area of other vertebrates. Dopamine immunoreactive fibers are found in the glomeruli of the olfactory bulbs, in ventral portions of the telencephalon, where a dense dopaminergic plexus innervates the area superficialis basalis and striatum, and in the diencephalon, where the inferior lobe is the most densely innervated structure. In the mesencephalon, the dopamine immunoreactive fibers are confined predominantly to the periventricular zone and lateral portions of the tectum. We conclude that much of the dopaminergic system in Raja radiata is strikingly similar to that seen in amniotes.

Histochemical identification of pallidal and striatal structures in the lizard Gekko gecko: Evidence for compartmentalization

The present study provides a description of the distribution patterns of enkephalin, substance P and dopamine immunoreactivity, and acetylcholinesterase activity in the striatum, nucleus accumbens, globus pallidus, and ventral pallidum of the Gekko gecko. The pallidal structures were identified on the basis of characteristic enkephalin and substance P immunoreactive plexus. The globus pallidus contains a very dense enkephalin immunoreactive woolly fiber plexus and a light and less extensive substance P immunoreactive plexus. The ventral pallidum is characterized by substance P and enkephalin immunoreactive woolly fiber plexus, which show a dense and moderate staining, respectively. The striatum and the nucleus accumbens were found to be inhomogeneous with respect to staining intensities for all four markers. Except for the enkephalin immunoreactivity distribution pattern in the striatum, the compartments that can be distinguished in material stained for these markers appear to coincide quite well.

Distribution of Dopamine in the Forebrain and Midbrain of the Red-Eared Turtle, <i>Pseudemys scripta elegans, </i>Reinvestigated Using Antibodies against Dopamine (Part 2 of 2)

The distribution of dopamine (DA) immunoreactivy in the forebrain and midbrain of the red-eared turtle, <i>Pseudemys scripta elegans, </i>was studied using recently developed antibodies against DA. DA-containing cells were found around the glomeruli of the olfactory bulb but not in the telencephalon proper. In the diencephalon DA cells were observed in the preoptic region, several parts of the periventricular hypothalamic nucleus, the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area and the pretectal posterodorsal nucleus. In the midbrain DA cells were found in the ventral tegmental area, the substantia nigra and the presumed reptilian homologue of the mammalian A8 cell group. Dopaminergic fibers and terminals were observed throughout the whole brain, particularly in the telencephalon and diencephalon. The olfactory tubercle, the striatum and the nucleus accumbens appear to have the most dense innervation, but the anterior olfactory nucleus and the septal area also show numerous DA fibers and terminals. Cortical areas are in general not densely innervated by DA fibers. Compared to the results obtained for a lizard, <i>Gekko gecko</i>, with the same antibodies, the results of the present study are very similar as regards the distribution of DA neurons, fibers and terminals. In having better developed DA cell groups in the midbrain and a stronger innervation of the striatum, <i>Pseudemys</i> resembles mammals more than does <i>Gekko</i>. In contrast, the many cerebrospinal fluid-contacting DA neurons in the hypothalamus of <i>Pseudemys</i> are a primitive feature of the diencephalon. The previous immunohistochemical study of <i>Gekko</i>, a lizard, and the present account of <i>Pseudemys</i>, a turtle, indicate that at least two different lines of evolution exist within the reptiles with regard to the DA innervation of the dorsal ventricular ridge. One, including turtles and, probably, crocodilians with a weak DA innervation; and another, represented by lizards, with a strong DA immunoreactivity.

The distribution of dopamine immunoreactivity in the forebrain and midbrain of the lizard Gekko gecko: an immunohistochemical study with antibodies against dopamine.

The distribution of dopamine (DA) immunoreactivity in the forebrain and the midbrain of the lizard Gekko gecko was studied by using recently developed antibodies against DA. Dopamine-containing cells were found around the glomeruli of the olfactory bulb, in several parts of the periventricular hypothalamic nucleus, in the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area and the pretectal posterodorsal nucleus of the diencephalon, and in the ventral tegmental area, the substantia nigra, and the presumed reptilian equivalent of the mammalian A8 cell group of the mesencephalon. Dopaminergic fibers and terminals were observed throughout the whole brain, but particularly in the diencephalon and the telencephalon. The nucleus accumbens appears to have the most dense innervation, but also the striatum, amygdaloid complex, olfactory tubercle, septum, and dorsal ventricular ridge (especially its superficial zone) show numerous DA-containing fibers and terminals. Except for the lateral cortex, cortical areas are not densely innervated by DA fibers. In several respects DA distribution in the gekkonid brain differs from that in other reptiles studied. For instance, in the Gekko the dorsal ventricular ridge is densely innervated by DA fibers, whereas in turtles and crocodiles the same structure shows only weak catecholaminergic histofluorescence. When compared to the distribution of DA immunoreactivity in mammals, it appears that the DA system in the gekkonid telencephalon resembles the distribution of DA in the limbic forebrain and striatum of mammals. Whether these similarities in distribution of DA also imply similarities in function will be discussed.

The dopaminergic innervation of the ventral striatum in the rat: a light- and electron-microscopical study with antibodies against dopamine.

Dopamine (DA) in the dorsal and ventral striatum is associated with different aspects of locomotor activity control. The ventral striatum may form an interface between the limbic system and the extrapyramidal motor system. The distribution of dopaminergic fibers in this interface position was studied in detail with a method applying antibodies against DA. Furthermore, the ultrastructural morphology of the DA fibers was examined by means of immuno-electron microscopy. The results show that DA immunoreactivity is distributed over the ventral striatum in a highly compartmentalized fashion. In the dorsal striatum few compartments were found. The DA fibers in the ventral striatum establish mainly symmetric synaptic contacts, preferably with dendritic shafts and spines. The results are discussed in relation to previous data concerning the light and electron-microscopic identification of catecholaminergic fibers in the ventral and dorsal striatum.

Immunohistological evidence of dopamine cells in the cephalic nervous system of the silkworm Bombyx mori. Coexistence of dopamine and ? endorphin-like substance in neurosecretory cells of the suboesophageal ganglion

Evidence of dopamine cells in the brain and the suboesophageal ganglion of the silkworm Bombyx mori was obtained immunohistologically in larvae and pupae. From six to eight and eight (two symmetrical groups of four) immunoreactive cells are present respectively in median and lateral protocerebral areas of the brain. In the suboesophageal ganglion, two cell clusters with dopamine immunoreactivity were observed. There was no clear difference in the nature of the immunohistochemical reaction and the number of cells between diapause- and non-diapause-egg producers, in both brains and suboesophageal ganglia. By examination of adjacent sections, it was possible to show that dopamine-immunoreactive cells in larval suboesophageal ganglia also contain an α endorphin-like substance.

Effects of calcium and limited proteolysis on membrane-bound and releasable dopamine beta-hydroxylase in adrenomedullary catecholamine granules.

Bovine chromaffin granules were shown to contain two potent proteolytic systems resulting in limited proteolysis of granule proteins at pH 6.0 in the cold in the presence of inhibitors of serine and thiol proteases. Calcium, whether added during lysis or remaining bound to the lysate protein during dialysis in non-chelating solutions, enhanced recoveries of total immunoreactive dopamine beta-hydroxylase (14% of total protein) and soluble enzyme (9% of lysate protein) due to degradation of of chromogranins. A pepstatin A-blockable, catepsin D-like proteolytic system converting membrane-bound enzyme to its soluble counterpart at pH 6.0 was detected in the granule membrane fraction.

Ultrastructural immunocytochemical study of the dopaminergic innervation of the rat lateral septum with anti-dopamine antibodies

The dopaminergic innervation of the rat lateral septum has been investigated at ultrastructural level by immunocytochemistry using the unlabelled peroxidase-anti-peroxidase method with antidopamine antibodies. The specificity of the reaction has been carefully checked by immunological and histochemical controls. A strong immunoreaction was observed in fibres of the lateral septum as well as in their cells of origin in the ventral tegmental area. In the lateral septum, dopamine-immunoreactive fibres were localized in two distinct areas. A first area, located ventrally in the anterior part of the septum was characterized by a high density of immunoreactive varicosities with barely visible intervaricose segments. A more dorsal area, extending throughout the anteroposterior region of the septum, was characterized by immunoreactive fibres in pericellular arrangements. Electron microscopic observations revealed no difference in the ultrastructure of dopamineimmunoreactive profiles in the different areas. Reaction product was found in vesicles, linked to microtubules and in the cytoplasm. Three types of vesicles were seen: (i) small vesicles (30–50 nm) with varying intensity of immunoreaction, filling up the varicosities; (ii) rare large clear vesicles (50–80 nm) with no internal immunoreaction; (iii) very rare large dense vesicles (50–100 nm) with a strong dopamine immunoreactivity. Labelled profiles were observed in clearly defined asymmetrical synaptic contacts with somata and dendrites. Due to the lack of previous work dealing with the use of anti-dopamine antibodies for electron microscope immunocytochemistry, our observations are compared to previous data obtained by more indirect labelling techniques.