Immunohistochemical evidence for colocalization of gamma-aminobutyric acid and serotonin in neurons of the ventral medulla oblongata projecting to the spinal cord

Fluorescence immunohistochemistry was used to analyze the medulla oblongata of colchicine-treated rats that had been incubated with guinea pig antibodies to serotonin (5-HT) and either rabbit or sheep antibodies to glutamic acid decarboxylase (GAD). Numerous cells in the rostral ventrolateral medulla in the region of nucleus raphe magnus were immunostained for either 5-HT or GAD. A substantial number of neurons showed positive immunoreactivity for both substances, and were most frequently observed in the lateral aspect of nucleus raphe magnus. In addition, a number of the 5-HT/GAD-containing neurons were retrogradely labelled with Fast blue dye that had been injected into the thoracic spinal cord. This work provides evidence for colocalization of the classical neurotransmitters 5-HT and GABA in single cells of the ventral medulla oblongata, some of which project to the spinal cord.

Glutamic acid decarboxylase- and peptide-immunoreactive neurons in cortex cerebri following development in isolation: evidence of homotypic and disturbed patterns in intraocular grafts

Fetal parietal cerebral cortex was transplanted to the anterior eye chamber of adult Sprague-Dawley rats. After two to three months the grafts, with or without colchicine treatment, were subjected to immunohistochemical analysis using antibodies against cholecystokinin (CCK), somatostatin (SOM), neuropeptide tyrosine (NPY), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI) and the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD). Cerebral cortex in situ of untreated and colchicine-treated rats was always analyzed in parallel. A dense plexus of CCK-immunoreactive fibers was distributed in all parts of the transplants, and after colchicine treatment a large number of CCK-positive cells was observed. These cells were markedly increased in number as compared to normal cortical tissue in colchicine-pretreated rats. The amount of NPY-immunoreactive cells was also markedly increased, whereas somatostatin-positive cells were found in numbers similar to those seen in cortex in situ. In the grafts only a few VIP- and PHI-positive fibers were seen with a few VIP-positive cell bodies, but no clearly discernible PHI-positive cells. A very dense plexus of GAD-positive fibers with an even distribution throughout the grafts was observed. Cortex in situ exhibited a lower density of GAD-immunoreactive fibers. Even after colchicine treatment the number of GAD-positive cells in the grafts was low. Using double-staining techniques, it was found that most of the few GAD-positive cells in the grafts were also NPY-positive, SOM-positive or, to a minor extent, CCK-positive. The present results demonstrate that several peptides and transmitter markers are expressed in cortical grafts in oculo, but marked differences in their expression can be observed in cortical tissue that has developed in isolation. Thus, the intraocular cortex graft, alone and in combination with other brain areas, should provide a useful model in which to study factors that regulate brain development.

Immunoreactive glutamic acid decarboxylase in the trigeminal nucleus caudalis of the cat: a light- and electron-microscopic analysis

This study used antisera directed against glutamic acid decarboxylase (GAD), the biosynthetic enzyme for gamma-aminobutyric acid (GABA), to examine the light- and electron-microscopic distribution of presumed GABA-ergic synapses in the medullary homologue of the cat spinal dorsal horn, the trigeminal nucleus caudalis. At the light-microscopic level, immunoreactive terminals were concentrated in the superficial dorsal horn, laminae I and II. Colchicine was generally ineffective in revealing the distribution of cell bodies. However, in two successful cases, the majority of labeled cells were found in the magnocellular layer, ventral to the substantia gelatinosa, a region that had a lower density of immunoreactive terminals. Other labeled neurons were scattered in laminae I and II. A variety of synaptic arrangements were found at the electron-microscopic level. These derived from two types of labeled terminals. One contained both small round vesicles and large dense-cored vesicles. The second contained small round and pleomorphic vesicles. Some immunoreactive GAD terminals contained a few flat vesicles. Labeled terminals predominantly formed axodendritic synapses, via symmetrical contacts. Several axoaxonic arrangements were also observed. In most cases, the GAD terminal (which did not contain dense-cored vesicles) was presynaptic to another vesicle-containing profile, including the scalloped central terminal thought to derive from primary afferents. Another population of labeled GAD terminals was found postsynaptic to unlabeled vesicle-containing profiles, including central terminals. These data indicate that inhibitory GABA-ergic controls in the trigeminal nucleus caudalis involve both presynaptic and postsynaptic mechanisms and are probably mediated via direct contacts onto ascending projection neurons, as well as via synaptic contacts onto nociceptive primary afferent fibers. The transmission of nociceptive messages by neurons of the spinal cord dorsal horn and trigeminal nucleus caudalis is subject to a variety of segmental and supraspinal controls. Pharmacological and electrophysiological studies have implicated the biogenic amines serotonin and norepinephrine, and the endogenous opioid peptides enkephalin and dynorphin, in those controls (Basbaum and Fields, 1978, 1984; Basbaum et al., 1983; Basbaum, 1985).(ABSTRACT TRUNCATED AT 400 WORDS)

Structure and mitotic stability of minichromosomes originating in yeast cells transformed with tandem dimers of CEN11 plasmids

Large (10.5-13.5 kbp) circular minichromosomes containing the centromere of chromosome 11 (CEN11) and the MET14 gene of Saccharomyces cerevisiae in the YRp7 vector are considerably more stable during mitosis than smaller ones containing only the 1.6 kbp CEN11 SalI-fragment. Yeast transformants obtained with a tandem dimeric and thus dicentric form derived from this DNA varied in the mitotic stability of the TRP1 marker of the vector. The largest group of transformants contained minichromosomes which carried deletions located quite specifically at one of the two centromeres in the dimer, eliminating its function in mitosis. This group included also some minichromosomes which had been modified by intramolecular tandem amplification of the subunit carrying the deletion without losing the centromere within the unmodified subunit. The second major group carried minichromosomes which had been monomerized. Monomerized minichromosomes showed the relative low degree of mitotic stability typical for the original minichromosomes containing the 1.6 kbp CEN11 SalI-fragment. Increasing numbers of additional subunits carrying the TRP1-ARS1 sequences but lacking additional centromeres improved the mitotic stability considerably.

The development of immunoreactivity for neuron-specific enolase of preoptic and septal neurons in dissociated cultures

The immunocytochemical visualization of neuron-specific enolase, which is a marker protein for differentiated neurons, was applied to follow the differentiation of preoptic and septal neurons in dissociated cultures. From 4 to 24 days in vitro, the relative numbers of stained neurons were counted and the staining intensity of individual neurons determined by absorbency measurements using a television-based densitometer. Whereas few stained cells could be observed at 4 DIV, 80% of the neurons were neuron-specific enolase-positive at 13 days in vitro. This value remained constant up to 24 days in vitro. The density of the immunoreaction product increased dramatically from 13 to 17 days in vitro and was still higher at 24 days in vitro. The glial and ependymal cells of the carpet, as well as neuroblasts, remained unstained. Comparison with morphological observations and immunocytochemical demonstration of neuronal peptides made earlier shows that expression of neuron-specific enolase closely parallels neuronal differentiation. These observations indicate that cultures derived from preoptic and septal neurons represent a viable model system for the study of neuronal maturation in vitro.

[3H]Diazepam binding in mammalian central nervous system: a pharmacological characterization

Two types of benzodiazepine binding sites for [3H]diazepam in mammalian central nervous tissue were identified using selective in vitro tissue culture and in situ kainic acid lesion techniques. These two binding sites were pharmacologically distinguished by differential displacement of the [3H]diazepam radioligand using the centrally active benzodiazepine, clonazepam, and the centrally inactive benzodiazepine, RO5-4864. Clonazepam-displaceable binding sites were found to be located principally on neuronal membranes, while RO5-4864-displaceable binding sites were found to be located on non-neuronal elements. These pharmacological distinctions can be used to characterize the predominant cell types which bind benzodiazepines in nervous tissue. It is suggested that one quantitative measure of different cell populations is the ratio of clonazepam- to RO5-4864-displaceable [3H]diazepam binding within a single neuronal tissue simple.

[Immobilization stress and its significance for psychosomatic medicine]

Results from a variety of different experiments with immoblization stress, an operationally well defined stressor, are discussed with particular emphasis on gastric ulcers and hypertension. Finally an integrative model of hypertension is presented using dopamine-beta-hydroxylase as a marker of sympathetic nervous system activity and discussing the results in the context of giving up as the final common pathway to changes in health according to the concept developed by Schmale.

Site-specific deletion at the replication origin of the antibiotic resistance factor R1

The recombinant plasmid pRK101 carrying the complete replication origin of the antibiotic resistance factor R1 suffers frequently a deletion of 218 base pairs, removing parts or all of the origin sequence. This deletion seems to occur always when the Pst-E fragment carrying the replication origin is inserted into the cloning vector pBR322 in an orientation where the direction of R1 replication is the same as that of the vector plasmid and frequently when it is inserted in the opposite direction. DNA sequence analysis around the junction site generated by the deletion in three independently isolated deletion mutants reveals that the deletion occurs at a specific site, namely the end of a 22 bp sequence which is repeated almost identically at the other end of a segment of 197 bp. During the deletion one repeat unit is removed whereas the other is retained. The DNA sequence included by the two repeats contains high symmetric structures, i.e. inverted repeats, direct repeats and palindromes which may represent regulatory sites of the origin.

Deoxyribonucleic acid synthesis in Saccharomyces cerevisiae cells permeabilized with ether

Cells of Saccharomyces cerevisiae permeabilized by treatment with ether take up and incorporate exogenous deoxynucleoside triphosphate into deoxyribonucleic acid (DNA). With rho(+) strains, more than 95% of the product was mitochondrial DNA (mtDNA). This report characterizes ether-permeabilized yeast cells and describes studies on the mechanism of mtDNA synthesis with this system. The initial rate of in vitro mtDNA synthesis with one strain (X2180-1Brho(+)) was close to the rate of mtDNA replication in vivo. The extent of synthesis after 45 min was sufficient for the duplication of about 25% of the total mtDNA in the cells. The incorporated radioactivity resulting from in vitro DNA synthesis appeared in fragments that were an average of 30% mitochondrial genome size. Density-labeling experiments showed that continuous strands of at least 7 kilobases after denaturation, and up to 25 kilobase pairs before denaturation, were synthesized by this system. Pulse-chase experiments demonstrated that a large proportion of DNA product after short labeling times appeared in 0.25-kilobase fragments (after denaturation), which served as precursors of high-molecular-weight DNA. It is not yet clear whether the short pieces participate in a mechanism of discontinuous replication similar to that of bacterial and animal cell chromosomal DNA or whether they are related to the rapidly turning over, short initiation sequence of animal cell mtDNA. In rho(0) strains, which lack mtDNA, the initial rate of nuclear DNA synthesis in vitro was 1 to 2% of the average in vivo rate. With temperature-sensitive DNA replication mutants (cdc8), the synthesis of nuclear DNA was temperature sensitive in vitro as well, and in vitro DNA synthesis was blocked in an initiation mutant (cdc7) that was shifted to the restrictive temperature before the ether treatment.

The nucleotide sequence of a DNA fragment from the replication origin of the antibiotic resistance factor R1drd19

The recombinant plasmid pRK101 contains a DNA fragment which carries the complete replication origin of the antibiotic resistance factor R1drd-19 inserted into the vector plasmid pBR322. In a spontaneously arising mutant of this plasmid (pRK103) a deletion of about 215 base pairs (bp) has been detected by heteroduplex analysis and mapping with restriction endonucleases. Essential parts of the replication origin must be located in the deleted sequence. The deletion mutant pRK103, in contrast to its parent plasmid pRK101 is not replicated under the control of the R1 replicon, even when the R1 factor or copy mutants of it are present within the same cell. These latter plasmids can complement a plasmid-specific protein not coded by pRK101 but essential for R1-directed replication. The nucleotide sequence of a 252 bp HpaII fragment covering about 170--200 bp of the deletion was determined. This piece of DNA is rich in G and C and contains a series of small palindromes, symmetrically arranged repeated sequences and short selfcomplementary structures which may be of significance for the initiation of the DNA replication. The possiblity that the sequenced DNA fragment comprises a major part of the replication origin of R1drd-19 is discussed.

Isolation and characterization of the minimal fragment required for autonomous replication ("basic replicon") of a copy mutant (pKN102) of the antibiotic resistance factor R1

The mini plasmids deriving from pKN102, a copy mutant of the antibiotic resistance factor R1drd-19 of E. coli, share a common DNA sequence of 2.6 kb, which carries the minimal functions for autonomous replication. By cloning of two PstI fragments of this region it could be demonstrated that the "basic replicon" is a DNA segment not larger than 1.8 kb, which carries the orgin of replication and the genetic information for at least two proteins. Protein F (NW=11.000 dalton) seems to be synthesed in larger amounts in minicells of E. coli than protein C (20.000). Plasmids containing this isolated replicon of R1 are completely compatible with the parental plasmid R1drd-19.

Deoxyribonucleic acid synthesis in permeabilized spheroplasts of Saccharomyces cerevisiae

Osmotically shocked spheroplasts from Saccharomyces cerevisiae incorporated deoxynucleoside triphosphates specifically into double-stranded nuclear and mitochondrial deoxyribonucleic acid (DNA). Results with this in vitro system for cells with and without mitochondrial DNA were compared. Strains lacking mitochondrial DNA were used to study nuclear DNA replication. With a temperature-sensitive mutant defective in DNA replication in vivo, DNA synthesis in vitro was temperature sensitive as well. The product of synthesis with all strains after very short labeling times consisted principally of short fragments that sedimented at approximately 4S in alkali; with longer pulse times or a chase with unlabeled nucleotides, they grew to a more heterogenous size, with an average of 6 to 8S and a maximum of 15S. There was little, if any, integration of these DNA fragments into the high-molecular-weight nuclear DNA. Analysis by CsCl density gradient centrifugation after incorporation of bromodeoxyuridine triphosphate showed that most of the product consisted of chains containing both preexisting and newly synthesized material, but there was also a small fraction (ca. 20%) in which the strands were fully synthesized in vitro. (32)P-label transfer ("nearest-neighbor") experiments demonstrated that at least a part of the material synthesized in vitro contained ribonucleic acid-DNA junctions. DNA pulse-labeled in vivo in a mutant capable of taking up thymidine 5'-monophosphate, sedimented in alkali at 4S, as in the case of the in vitro experiments.

Evidence that GABA is not the afferent transmitter in the cochlea

The GABA antagonists picrotoxin, bicuculline and bicuculline-methochloride, when applied intracochlearly, do not affect the compound action potential of the cochlear nerve. It is therefore concluded that these drugs do not interfere with afferent synaptic transmission, and therefore that GABA is not the afferent transmitter. With very high doses, picrotoxin as well as bicuculline-methochloride partially block the efferent synapses. This effect is most likely to be unspecific, but shows that with the technique used the agents can reach the synaptic site.

[Morphology and physiopathology of Billroth I gastroduodenostomy]

97 patients subjected from 1 to 7 years previously to partial gastric resection by gastroduodenostomy (Billroth I) have been studied endoscopically and radiologically. Acid secretion after pentagastrin injection has also been determined. The most frequent mucous alterations identified by endoscopy were erosions in the stomach residue with inflammatory granulation in the anastomosis region. Recurrent ulcers were observed in 3% of cases. Acid secretion was reduced in 87% by comparison with the preoperative picture. The quantity of residual recretion depended on the greater curvature of the residual stomach. Radiological studies highlighted functional modifications indicative of organized motility in the residual stomach and pseudopyloric function at anastomosis level making coordinated draining possible.

[Morphology and pathophysiology of Billroth I gastro-duodenostomy (author's transl)]

Endoscopic and radiological studies were undertaken in 97 patients who had had a partial gastric resection with gastro-duodenostomy (Billroth I) one to seven years previously. Acid secretion was also analyzed after injection of pentagastrin. The most frequent mucosal changes seen at endoscopy were erosion in the residual stomach, with inflammatory granulation in the region of the anastomosis. Recurrent ulcers were seen in 3%. Acid secretion was reduced by 87% from its pre-operative level. The amount of residual secretion depended on the length of the greater curvature in the residual stomach. Radiological studies revealed functional changes indicating that there is a motility pattern in the residual stomach and a pseudopyloric function at the anastomosis which makes co-ordinated emptying possible.