1B1075: a brain- and pituitary-specific mRNA that encodes a novel chromogranin/secretogranin-like component of intracellular vesicles.

The rat 1B1075 mRNA encodes a 533-residue novel chromogranin/secretogranin-like acidic protein that contains an apparent secretion signal, several pairs of tandem basic residues, and internally repeated sequence elements. 1B1075 transcripts are detected, by blotting and in situ hybridization, at the highest levels in the neocortex, hippocampus, cerebellar cortex, selected pontine and diencephalic nuclei, and presumptive pituitary corticotrophs, at lower levels in specific nuclei in most other brain regions, but in none of several other tissues. Utilizing antisera to several nonoverlapping synthetic peptide fragments of the predicted protein sequence, we detect a brain- and pituitary-specific 57-kDa protein in cellular processes and fiber tracts, generally consistent with axonal transport from the cell bodies identified by in situ hybridization. Ultrastructural studies demonstrate that this protein is a component of intraneuronal vesicles in axons and vesicle-like structures in dendrites. Based on these data, we suggest the name Secretogranin III for the 1B1075 gene product. In related collaborative studies, a mouse deleted for the 1B1075-homologous gene has been produced that should allow assessment of its physiological role.

Regional distribution of progesterone and 5 alpha-pregnane-3,20-dione in rat brain during progesterone-induced "anesthesia".

Progesterone and 5 alpha-pregnane-3,20-dione (5 alpha-DHP) concentrations were measured in seven brain areas and in plasma during "anesthesia" induced by progesterone (1-2 mg IV) in female rats. The highest levels of progesterone were detected in the striatum and hypothalamus (23.3 +/- 5.27 and 22.7 +/- 4.30 micrograms/g +/- SEM, respectively); these concentrations were approximately 1000 times higher than those during the post-ovulatory phase. Highest levels of 5 alpha-DHP were detected in the striatum and hippocampus (11.5 +/- 1.74 and 10.4 +/- 3.15 micrograms/g +/- SEM, respectively). The ratio of 5 alpha-DHP to progesterone was approximately 100 times higher in brain tissue than in plasma. We conclude that a conversion of progesterone to 5 alpha-DHP occurs in the brain during the course of progesterone-induced "anesthesia". This metabolic step may be an important contributory factor to the anesthetic potency of progesterone.

Comparison of synenkephalin and methionine enkephalin immunocytochemistry in rat brain.

Immunocytochemistry using an antiserum to the C-terminal octapeptide of synenkephalin, proenkephalin(63-70), was performed throughout the rat brain and revealed numerous immunopositive fibers and some cell bodies. The morphology and distribution of synenkephalin immunoreactivity was extremely similar to that of a commercial methionine enkephalin (Met-ENK) antiserum. Colchicine pretreatment allowed the immunostaining of cell bodies not otherwise possible without pretreatment, but did not affect the distribution of immunoreactive fibers. Using 6 microns serial sections, we were able to colocalize synenkephalin and Met-ENK immunoreactivities in gigantocellular neurons of the medullary reticular formation. Preabsorption of the antiserum with [Tyr63]proenkephalin(63-70) octapeptide (YEESHLLA) completely eliminated immunoreactivity in the rat brain, while preabsorption with all other peptides used had no detectable effect. We conclude that our antiserum to synenkephalin is specific for enkephalinergic cell bodies, fibers and terminals. The synenkephalin antiserum used in these studies may have advantages over other antisera utilized for immunocytochemical detection of proenkephalin gene expression.

[Contents of serotonin and 5-hydroxyindoleacetic acid in the rabbit brain after long-term administration of lithium oxybutyrate]. / Soderzhanie serotonina i 5-oksiindoluksusnoi kisloty v mozge krolikovpri dlitel'nom naznachenii oksibutirata litiia.

Serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels in rat brain were analysed 24 hours after 7-, 15-, 29- days lithium hydroxybutyrate (LH) injections (10 mg/kg daily). After 7 days the drug reduced 5-HT in hypothalamus and 5-HIAA in the mid brain by 35%. After 15 days LH decreased 5-HT in striatum, hypothalamus by 32 and 17% and 5-HIAA in thalamus, hypothalamus by 28 and 44% respectively. After 29 days LH diminished 5-HT in striatum, hippocampus, amygdala by 24, 29 and 32% and 5-HIAA--in hypothalamus by 42%. The role of adaptative changes and stabilization processes in the central serotoninergic system in mechanism of LH psychotropic effects is discussed.

[5-HT1 receptors in rats with amnesia]. / Serotoninovye retseptory pervogo tipa pri amnezii u krys.

5-HT1 receptors of the amygdala, midbrain's central gray substance, hippocampus and frontal cortex of the rats were investigated during the memory trace retrieval, using the model of "psychogenic" amnesia. It was found that specific binding of 3H 5-HT in amygdala and central gray substance was decreased in the rats with passive avoidance retention. 3H 5-HT binding in the amnesic rats didn't differ from the control animals. Absence of decrease of 5-HT1 receptors number could be considered as one of the possible mechanisms of the memory trace non-retrieval due to amnesia or its consequence.

Somatostatin-containing neurons in the mouse brain: an immunohistochemical study and comparison with the rat brain.

The distribution of somatostatin-containing neurons in mice of both sexes was immunohistochemically examined and compared with that in rats. In radioimmunoassay the relative somatostatin content in the mouse brain was 2-3 times higher than that in the rat. The overall immunohistochemical staining for somatostatin was much stronger and more prominent in the mouse than in the rat. Although the distribution pattern of somatostatin immunoreactivity was basically the same between the two animals, several regions, especially the nucleus anterior hypothalami and the nucleus interpeduncularis, were found to contain large aggregates of somatostatin-immunoreactive neurons in the mouse brain but not in the rat. The electrolytic lesions to the nucleus anterior hypothalami caused a marked decrease in somatostatin immunoreactivity of the outer layer of the median eminence in the mouse. This suggests that the nucleus anterior hypothalami is an additional source of somatostatin for the median eminence in the mouse. The differences recognized between the species are interesting from functional and evolutionary points of view.

[The asymmetry of the free amino acid pool in sections of the rat brain]. / Asimmetriia fonda svobodnykh aminokislot v nekotorykh uchastkakh mozga krys.

The content of free amino acid pool in symmetric regions of cortex, hypothalamus, midbrain and blood of rats which had produced the movement conditioned reflex strengthened by feeding was studied. It was established that the "untrained" rats have higher content of free amino acid pool in their blood. The brain of the experimental animals revealed the biochemical asymmetry which was marked by the differences in free amino acid pool distribution between the left and right halves of the studied regions of brain. It was shown that left sided asymmetry animals i.e. animals with heightened content of free amino acid pool in the left half of the brain dominated in the "untrained" group of rats. The supposition was expressed that this biochemical asymmetry may contribute to the ability of animals to learn.

Distribution of serotonin 5-HT1C receptor mRNA in adult rat brain.

Based on in situ hybridization histochemistry (ISHH), we describe the anatomical distribution of the serotonin 5-HT1C receptor mRNA. In addition to the very high levels in epithelial cells of the choroid plexus, 5-HT1C receptor mRNA is found throughout the limbic system, in catecholaminergic cells and in serotonergic neurons. Receptor transcripts are also present in the hypothalamus, numerous motor nuclei and the subthalamus. Our results correlate well with serotonin (5-HT) innervation and receptor binding. Receptor mRNA is present in many brain structures in addition to regions previously shown to have 5-HT1C receptor binding. The distribution of this receptor mRNA suggests that the 5-HT1C receptor may mediate a number of the central effects of 5-HT.

Regional variation in rat brain proton relaxation times and water content.

Relaxation times (T1 and T2) and water content are measured in frontal cortex, amygdaloid cortex, hippocampus, mid-brain and cerebellum of rat brain. Differences are found in relaxation times, between areas containing a mixture of grey and white matter, and grey matter only. Differences were also found between certain grey matter areas. Relaxation times correlated with water content.

Further evidence for excitatory amino acid transmission in lamprey reticulospinal neurons: selective retrograde labeling with (3H)D-aspartate.

The distribution of radiolabeled neurons in the brain stem of Lampetra fluviatilis was studied following unilateral injections of (3H)D-aspartate in the rostral spinal cord. After survival periods of 1-3 days, labeled perikarya were present within and nearby the posterior, middle, and anterior rhombencephalic reticular nuclei and in the mesencephalic reticular nucleus. The highest number of (3H)D-aspartate labeled cell bodies were present in the posterior rhombencephalic reticular nucleus. The labeled reticulospinal neurons were distributed mainly ipsilateral to the injection site and included the giant Müller cells as well as medium-sized and small neurons. Contralateral labeling occurred in cell bodies scattered along the lateral margin of the rhombencephalic reticular formation, the most rostral of these contralaterally projecting neurons being the Mauthner cell. The (3H)D-aspartate labeling correlates with previous electrophysiological studies showing that lamprey reticulospinal neurons utilize excitatory amino acid transmission.

Distribution of serotonin in the brain of the mormyrid teleost Gnathonemus petersii.

The distribution of serotonin-immunoreactive neurons and fibers was studied in the highly developed brain of the weakly electric fish Gnathonemus petersii with the aid of specific antibodies against serotonin. Serotoninergic cell bodies occur in three regions: the raphe region of the brainstem, the hypothalamus, and the transition zone between the dorsal thalamus and the pretectum. Serotoninergic raphe neurons are clustered in three groups: nucleus raphes superior, intermedius, and inferior. The latter has not been described in other teleosts and thus might be the source of the serotoninergic innervation of specific mormyrid electrosensory brain regions. Most hypothalamic serotoninergic neurons have cerebrospinal-fluid (CSF)-contacting processes and thus belong to the paraventricular organ (PVO), which in Gnathonemus is located around a number of small infundibular recesses. The distribution of serotonin in the PVO precisely matches the distribution of dopamine, as described previously. Serotoninergic cells in the thalamopretectal transition zone also have been described in other teleosts, but not in other vertebrate groups, and thus seem to represent a teleostean specialization. Serotoninergic fiber density is especially high in the medial forebrain bundle and surrounding preoptic and hypothalamic regions as well as in several telencephalic and preoptic subependymal plexus. Serotoninergic fibers appear to be almost completely absent in the large and differentiated corpus and valvula cerebelli. Comparison with the literature on teleostean serotoninergic innervation patterns reveals several mormyrid specializations, including the absence of serotonin in large parts of the mormyrid telencephalic lobes, a differentiated innervation pattern of distinct electrosensory and mechanosensory subnuclei of the torus semicircularis, a refined serotoninergic lamination pattern in the midbrain tectum, and a prominent innervation of the electrosensory lateral line lobe, the associated caudal cerebellar lobe, and the electromotor medullary relay nucleus. A distinct innervation of several types of (pre)motor neurons, such as the Mauthner cells and facial motor neurons, has not been reported previously for other teleosts. Consequently, the distribution of serotoninergic fibers as well as neurons in the mormyrid brain is substantially adapted to the high degree of differentiation of its electrosensory and telencephalic brain regions, but serotoninergic innervation is not involved in the circuitry of the most impressive part of the mormyrid brain; i.e., its large corpus and valvula cerebelli.

Selective vulnerability of pigmented dopaminergic neurons in Parkinson's disease.

From a neuropathological point, the diagnosis of Parkinson's disease is confirmed by a neuronal cell loss and the presence of Lewy bodies in the substantia nigra. In Parkinson's disease, the precise type of nigral neuron which degenerate still remains unknown. Are all types of neuron similarly injured, are only subpopulations of neurons vulnerable? In an attempt to answer the question, a qualitative and quantitative analysis of the distribution of dopaminergic cells, as identified by immunohistochemistry with a specific antibody against tyrosine hydroxylase, was performed in the ventral mesencephalon of control subjects and patients who died with a clinical diagnosis of Parkinson's disease. In control brains, two types of catecholaminergic neurons were evidenced; some contain visible-neuromelanin, others do not. In patients with Parkinson's disease, the tyrosine hydroxylase positive cells which contained the pigment were the most vulnerable.

Iodinated-NPY binding sites: autoradiographic study in the rat brain.

Several authors have described the presence of iodinated neuropeptide-Y binding sites on membranes of the mammalian CNS. In the present study we show a mapping of iodinated-NPY binding sites in the rat brain using receptor autoradiography. The sections were incubated with 125I-Bolton-Hunter coupled NPY (0.5-03 nM), in the absence or presence of 1 microM cold NPY. Some autoradiograms are studied by means of an image analyzer (VDC 501 Tesak) equipped with the host computer PDP 11 Digital, in order to enhance the contrast of the labeling. A very high density of NPY receptors is present in the limbic regions (hippocampus, amygdaloid complex, septal nuclei), in the cortex, and in some thalamic nuclei, while in some hypothalamic regions (paraventricular nucleus and median eminence) we detected a lower amount of NPY receptors. At the mesencephalic level, the substantia nigra presents a very high density of NPY receptors.

Distribution of substance P, vasoactive intestinal polypeptide and serotonin immunoreactive structures in the central nervous system of the lizard, Lacerta agilis.

The distribution of substance P (SP), vasoactive intestinal polypeptide (VIP) and serotonin (5-HT) containing structures in the central nervous system of the lizard, Lacerta agilis, were investigated with the aid of the peroxidase-antiperoxidase immunohistochemical method. SP and 5-HT nerve fibers are found almost all over the brain, whereas VIP fibers are mainly observed in the limbic area, in the periventricular gray matter of the diencephalon and in the brain stem. The cells of origin are located in the telencephalon for the SP, in the mesencephalic tegmentum for the VIP, and in the midline and the basis of the brain stem for the 5-HT. In addition to the known paraventricular organ in the diencephalon VIP and 5-HT immunoreactive cells are found in the ependymal layer of the rostral part of the lateral ventricle.

[Effects of repeated acupuncture action on pain sensitivity and beta-endorphin contents of the hypothalamus and midbrain of the rat]. / Vliianie mnogokratnogo akupunkturnogo vozdeistviia na bolevuiu chuvstvitel'nost' i soderzhanie beta-éndorfina v gipotalamuse i srednem mozge krys.

Changes in latencies (L) of nociceptive (NC) reactions of hot plate (HP) tail flick (TF) tests and dynamics of beta-endorphin (beta-ED) in hypothalamus and midbrain were studied in albino rats receiving 15 sessions of acupuncture (A) (20 min daily in bilateral Ho-Ku). It was shown that repeated A facilitated prolongation of LHP and LTF as compared to baseline and control levels. A decrease of the anti-NC systems capacity for activation in response to each A stimulation was observed. The dynamics of beta-endorphin in hypothalamus showed an opposite tendency as compared to that in midbrain. It is suggested that such a correlation of beta-ED activities in midbrain and hypothalamus might be one of the reasons for anti-NC mechanisms adaptation to A.

Predominant cytosolic distribution of serotonin in rat pineal gland in contrast to biogenic monoamine localization in midbrain and adrenal gland.

The subcellular distribution of serotonin and norepinephrine in the rat pineal gland was studied by tissue fractionation and compared with that of biogenic monoamines in the adrenal gland and midbrain. Homogenized tissues were fractionated by ultracentrifugation or by filtration through cellulose ester membranes. Most of the epinephrine (70-80%) and norepinephrine (62-82%) present in the adrenal glands was detected in the particulate fraction. The same distribution was found for serotonin (68.5%) and norepinephrine (59%) in the midbrain and for norepinephrine (62.5%) in the pineal gland. However, most of the serotonin in the pineal was found in the soluble fraction (89.5-98%). This suggests that the great majority of serotonin in the rat pinealocytes is cytosolic and thus is not stored in subcellular vesicles, in contrast to the biogenic monoamines in the midbrain or adrenal gland.

[Prevention of arrhythmia in acute ischemia in conscious animals using a serotonin analog]. / Preduprezhdenie aritmii pri ostroi ishemii u bodrstvuiushchikh zhivotnykh s pomoshch'iu analoga serotonina.

The state of the serotonergic system was studied in adaptation of rats to short-term non-damaging stress actions along with the possibility of protecting the heart of conscious animals against arrhythmias in acute ischemia with the serotonin analogue 4-nitro-5-methoxytryptamine. It was shown that the adaptation resulted in a significant increase in rat midbrain serotonin by 70%. Preliminary administration of the serotonin analogue 3 fold reduced the total duration of arrhythmias and approximately 5 fold--the heart fibrillation rate and the death rate of animals in acute ischemia. The data obtained are in agreement with the idea on the role of stress-limiting systems in prevention of stress-induced and ischemic damages of the organism. They show that protective effects of metabolites of these systems can be successfully reproduced with their synthetic analogues or activators.

Mesencephalic innervation of the turtle retina by a single serotonin-containing neuron.

Co-localization of retrograde transported Nuclear yellow and serotonin immunoreactivity revealed the existence of a central serotonergic projection to the retina in the turtle Pseudemys scripta elegans. This serotonergic retinopetal system consists of only one fiber originating in the contralateral caudal mesencephalon. In the retina, the fiber arborizes exclusively in the temporal hemisphere, covering about one third of the total retinal surface. Interestingly this projecting area lies in the part of the retina, to which binocular perception can be attributed.

Noradrenergic neurons with divergent projections to the motor trigeminal nucleus and the spinal cord: a double retrograde neuronal labeling study.

Double retrograde axonal tracing was combined with the indirect immunofluorescence antibody method to determine whether noradrenergic neurons have divergent projections to the motor nucleus of the trigeminal nerve and the spinal cord. Rhodamine-labeled microspheres were injected into the motor trigeminal nucleus and True Blue was deposited into lumbar segments of the spinal cord. After a 10-18-day survival period, brainstem sections were processed for immunofluorescence staining of noradrenergic neurons using antibodies to rat dopamine-beta-hydroxylase. Rhodamine-labeled noradrenergic neurons were observed ipsilaterally throughout the A5 and A7 groups; the contralateral A5 and A7 groups contained few rhodamine-labeled cells. A few rhodamine-labeled noradrenergic neurons were observed in the locus coeruleus and subcoeruleus. True Blue-labeled noradrenergic neurons were identified in the A5 and A7 groups, in the ventral part of the locus coeruleus and in the subcoeruleus. Double retrogradely labeled noradrenergic neurons were observed in the A5 and A7 groups but not in the locus coeruleus and subcoeruleus. Of the total number of rhodamine-labeled noradrenergic cells, a large percentage also contained True Blue: 54% in the caudal A5 group, 59% in the rostral A5 group, and 72% in the A7 group. Of the total number of True Blue-labeled noradrenergic neurons, the percentage of double retrogradely labeled cells was 33% in the caudal A5 group, 46% in the rostral A5 group, and 56% in the A7 group. The findings of this study provide the first anatomic evidence for the existence of a prominent population of noradrenergic cells in the A5 and A7 groups with divergent projections to the motor trigeminal nucleus and the spinal cord. We propose that this subpopulation of noradrenergic neurons in the A5 and A7 groups influences motoneurons at multiple levels of the neuraxis.