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Biomedical subjects

J D Barchas

Publications and source records attributed to J D Barchas.

At least 91 records · Page 5Linked to original sources
PubMed1983

Immunohistochemical distribution of dynorphin B in rat brain: relation to dynorphin A and alpha-neo-endorphin systems.

A specific antiserum was prepared against dynorphin B, an endogenous opioid peptide contained in a recently isolated 4,000-dalton dynorphin. The antiserum did not crossreact with dynorphin A, alpha-neo-endorphin, beta-neo-endorphin, dynorphin-(1-8), or [Leu]enkephalin. In immunohistochemical staining experiments on frozen sections through rat brains from normal and colchicine-treated animals, the antiserum labeled the same neuronal fiber systems previously described as containing both dynorphin A and alpha-neo-endorphin immunoreactive material. The alpha-neo-endorphin/dynorphin A immunoreactive perikarya in the hypothalamic magnocellular nuclei also were labeled by the dynorphin B antiserum. In addition, the dynorphin B antiserum revealed groups of immunoreactive neuronal cell bodies in several other hypothalamic and extrahypothalamic areas, including brain-stem, midbrain, central nucleus of amygdala, and in the dorsomedial, lateral, and anterior nuclei of hypothalamus. These perikarya had not been detected in previous studies that used dynorphin A and alpha-neo-endorphin antisera. The findings are in agreement with recent studies demonstrating a common precursor for dynorphin A, dynorphin B, and alpha-neo-endorphin. The apparently wider distribution of dynorphin B immunoreactive cell bodies compared to alpha-neo-endorphin/dynorphin A immunoreactive perikarya may be a reflection of differential processing of the precursor in different brain regions.

Animals↗
PubMed1983

Genes for catecholamine biosynthesis: cloning by expression and identification of the cDNA for rat dopamine beta-hydroxylase.

mRNA for dopamine beta-hydroxylase [3,4-dihydroxyphenylethylamine, ascorbate:oxygen oxidoreductase (beta-hydroxylating), EC 1.14.17.1] has been partially purified from poly(A)+ mRNA isolated from a rat pheochromocytoma cell line. Shared antigenic determinants between tyrosine hydroxylase and dopamine beta-hydroxylase allowed us to obtain enriched fractions of dopamine beta-hydroxylase mRNA by immunoprecipitating translated mRNA products with tyrosine hydroxylase antisera. The enriched dopamine beta-hydroxylase mRNA was used to synthesize the corresponding cDNAs, which were then cloned in the Pst I site of pBR322. Recombinant colonies were characterized by an in situ colony immunoassay and hybrid-selected translation. In vitro translation of the mRNA selected from one recombinant clone produced a protein of 75,000 daltons that comigrated with authentic dopamine beta-hydroxylase. Partial proteolysis of both authentic dopamine beta-hydroxylase and the protein encoded by the recombinant clone produced identical peptide patterns.

Animals↗
PubMed1983

Epinephrine and norepinephrine responses in continuously collected human plasma to a series of stressors.

The present study employed continuous blood withdrawal to examine epinephrine and norepinephrine responses to a cognitive stressor (mental arithmetic), active physical stressors (handgrip and knee bends), passive painful stressors (venipuncture and cold pressor), and a medical procedure that was considered nonstressful (blood pressure measurements). The data were analyzed by analysis of variance (ANOVA) and by time series analysis. The ANOVA indicated that epinephrine and norepinephrine increased significantly in response to the stressors. Epinephrine showed a greater increase to the cognitive stressor than to the others. Time series analysis, however, showed a more varied pattern. It indicated that the height and duration of response differed considerably across subjects and across interventions. The results from both analytic procedures are compared and discussed in terms of current hypotheses of catecholamine response.

Adult↗
PubMed1983

Regional distribution of dynorphin and neo-endorphin peptides in rat brain, spinal cord, and pituitary.

Five products of the dynorphin gene--alpha-neo-endorphin, beta-neo-endorphin, dynorphin A, dynorphin A-(1-8), and dynorphin B--were measured in various regions of rat brain and in rat spinal cord and pituitary. Specific antisera were used, supplemented by gel permeation analysis and high performance liquid chromatography, confirming the presence of dynorphin-32, dynorphin A, and dynorphin B in rat brain. In whole brain, alpha-neo-endorphin, dynorphin A-(1-8), and dynorphin B are present in much greater amounts than beta-neo-endorphin or dynorphin A. Although a general parallelism was found in the distribution of the five peptides, there were also noteworthy exceptions, suggesting that differential processing may occur.

Animals↗
PubMed1983

Gastrin-releasing peptide-related peptides in a human malignant lung carcinoid tumor.

Recent immunohistochemical findings have indicated the presence of gastrin-releasing peptide in normal and pathological human lungs. Gastrin-releasing peptide is a 27-amino acid peptide isolated from porcine gut which bears considerable carboxyterminal homology with bombesin. We have characterized the gastrin-releasing peptide-like peptides present in a human malignant lung carcinoid tumor by gel chromatography and reverse-phase high-performance liquid chromatography. Our results show that this tumor did not contain bombesin; however, this tumor expressed a gastrin-releasing peptide-like compound, several amino-terminal fragments, and a carboxy-terminal fragment of gastrin-releasing peptide.

Amino Acid Sequence↗
PubMed1982

Blood pressure elevation in rats by peripheral administration of Tyr-Gly-Gly-Phe-Met-Arg-Phe and the invertebrate neuropeptide, Phe-Met-Arg-Phe-NH2.

Phe-Met-Arg-Phe-NH2 (FMRFamide), injected at less than 1 mumol/kg intravenously in the anesthetized rat, produces sharp elevations of blood pressure and changes in respiration. The effects were dependent on the carboxyterminal Arg-Phe (RF) configuration and were stereospecific for these two amino acids. A related peptide with RF carboxyterminus, gamma 1-melanotropic stimulating hormone, also had potent blood pressure stimulating activity. The mechanisms underlying the pressor effect of FMRFamide have not yet been established but this pressor action was not significantly attenuated by standard pharmacologic antagonists or prevented by removal of the adrenal or pituitary gland.

Animals↗
PubMed1982

Tyrosine hydroxylase activation. Comparison of in vitro phosphorylation and in vivo administration of haloperidol.

Rat striatal tyrosine hydroxylase (TH) was assayed 2 hr following treatment with 1 mg/kg haloperidol. TH activity in striata from haloperidol-treated rats (haloperidol TH) was increased significantly relative to control when assayed at pH 7.0, but not at pH 6.0, in the presence of 175 muM tetrahydrobiopterin (BH4). TH was also phosphorylated in vitro, catalyzed by sufficient quantities of the catalytic subunit of bovine heart protein kinase to cause greater than 90% activation after 10 min. TH was activated by phosphorylation at both pH 6.0 and pH 7.0, but the activation was greater at pH 7.0. Haloperidol TH, activated relative to control TH at pH 7.0, was activated by phosphorylation, but there was no difference between haloperidol TH and control TH activity at either pH 6.0 or 7.0 following phosphorylation. Comparison of Lineweaver-Burk plots of nonphosphorylated and phosphorylated TH indicated that activation by phosphorylation was due to a 5-fold change in Km for BH4 and a 2-fold change in Vmax at pH 7.0. Haloperidol TH kinetics were intermediate between those of nonphosphorylated and phosphorylated TH at pH 7.0. Analysis by Lineweaver-Burk, Hanes-Woolf, and Eadie-Scatchard plots suggested that the haloperidol TH kinetic data were the result of a mixture of two forms of the enzyme, with different affinities for cofactor. Theoretical calculations of TH activity of mixtures of nonphosphorylated and phosphorylated TH suggested that the haloperidol data could be explained by postulating a mixture of 25-35% phosphorylated TH molecules with 65-75% nonphosphorylated TH molecules. An hypothesis of the role of TH phosphorylation during conditions of increased neuronal firing rate, such as may occur with haloperidol treatment, is presented.

Animals↗
PubMed1982

Monoamine metabolite concentrations in the cerebrospinal fluid of normal and narcoleptic dogs.

Because of the similarity between human and canine narcolepsy, an animal model has emerged with which to investigate the neurochemical basis of the disease. In this study, in vivo differences in cerebral neurotransmitter function between normal and affected dogs were measured by comparing, before and after probenecid administration, the concentrations in cisternal cerebrospinal fluid of the monoamine metabolites 5-hydroxyindoleacetic acid, homovanillic acid, 3,4-dihydroxyphenylacetic acid, and 3-methoxy-4-hydroxyphenylethylene glycol. Cisternal cerebrospinal fluid was collected from the cisterna magna of anaesthetized animals, and samples were analyzed for the metabolites and probenecid using combined gas chromatography-mass spectrometry. The concentrations of both the conjugated and non-conjugated forms of each of the metabolites were determined in all samples and the role of conjugation in cerebral monoamine metabolism is discussed. Before probenecid treatment, comparisons of metabolite concentrations in samples from normal versus narcoleptic dogs showed significantly lower amounts of the dopamine and of the 5-hydroxytryptamine metabolites in CSF from the affected animals. After probenecid administration, the concentrations in the CSF of all the metabolites increased. However, the amounts of 5-hydroxyindoleacetic acid, and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol, in samples from narcoleptic dogs were significantly lower than those found in samples from normal dogs. The implications of these results for our understanding of the neurochemical basis of REM sleep initiation and for treatment of narcolepsy/cataplexy are discussed.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Epinephrine, norepinephrine, dopamine and serotonin: differential effects of acute and chronic stress on regional brain amines.

Following acute cold swim stress, hypothalamic epinephrine concentrations were markedly lowered and remained decreased for 24 h, while norepinephrine concentrations were decreased, but returned to baseline within 14 h. With oscillation stress repeated daily for 21 days, hypothalamic norepinephrine, hypothalamic epinephrine, and hippocampal norepinephrine turnover were decreased and absolute concentrations were increased. Repeated stress had little effect on serotonin, dopamine or their metabolites. These results suggest that hypothalamic epinephrine concentration and turnover are particularly responsive to acute and chronic stress. The decreased epinephrine and norepinephrine turnover under chronic stress may be responsible in part for the behavioral and endocrine changes observed in chronically stressed rats.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Distribution of norepinephrine, epinephrine, dopamine, serotonin, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid in dog brain.

The distribution and endogenous concentrations of norepinephrine, epinephrine, dopamine, serotonin, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid were determined in the brains of adult dogs. Norepinephrine and epinephrine were localized primarily in 'central core' areas in brain stem and hypothalamus. Dopamine (DA) and its major metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acids (HVA), were localized primarily in basal ganglia with relatively high concentrations also found in amygdala, septum and substantia nigra. HVA was also found in relatively high concentrations in areas where DA concentrations was very low. Serotonin and 5-hydroxyindole-3-acetic acid levels were highest in brain stem, hypothalamus, globus pallidus and nucleus accumbens. Epinephrine levels were higher than in previously studied species, at times as much as 25-30% of norepinephrine and frequently greater than dopamine in brain stem and hypothalamus. Using the ratios 5-hydroxyindole-3-acetic acid/serotonin and homovanillic acid/dopamine as indicators of serotonin and dopamine turnover and utilization, both putative transmitters were found to be generally more highly utilized in areas of lower concentration, especially in brain stem and cortex. Catecholamines were found to be unconjugated in dog brain. DOPAC and HVA were found to exist primarily in the unconjugated form. DOPAC was found to be slightly conjugated in most areas while 10-20% of HVA was present in the conjugated form in most cases.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Corticosterone: a critical factor in an opioid form of stress-induced analgesia.

The finding that some opioid-mediated forms of stress-induced analgesia are antagonized by hypophysectomy and dexamethasone has led to the suggestion that beta-endorphin, released from the pituitary, may mediate these analgesic reactions. "Long-term analgesia" (an opioid-mediated form of stress-induced analgesia), which is blocked by dexamethasone and hypophysectomy, was also blocked by adrenalectomy and reinstated with corticosterone therapy. Corticosterone is proposed to play a permissive role in long-term analgesia and to be a critical hormone mediating this phenomenon.

Adrenalectomy↗