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Biomedical subjects

J D Barchas

Publications and source records attributed to J D Barchas.

At least 127 records · Page 7Linked to original sources
PubMed1981

Novel peptide neuronal system in rat brain and pituitary.

Immunohistofluorescence studies of the rat central nervous system with antibodies to Phe-Met-Arg-Phe-NH2 (molluskan cardioexcitatory peptide) revealed a widespread neuronal system in the brain, spinal cord, and posterior pituitary. Immunoreactive axons and cell bodies were mainly located in cortical, limbic, and hypothalamic areas. Immunostaining of serial sections of the brain and pituitary showed that the Phe-Met-Arg-Phe-NH2 immunoreactive neurons were different from neurons labeled by antibodies to either Met-enkephalin or the putative Met-enkephalin precursor Tyr-Gly-Gly-Phe-Met-Arg-Phe, which is structurally related to Phe-Met-Arg-Phe-NH2. Control staining by antiserum absorption and radioimmunoassay indicated that the antibodies that caused the specific immunofluorescence recognized peptides with an amidated Arg-Phe sequence at the carboxyl terminus.

Animals↗
PubMed1981

Central and peripheral contributions to hypothalamic epinephrine.

Hypothalamic epinephrine concentrations were examined following adrenal demedullation or after surgical hemisection of ascending projections to the hypothalamus. Following surgical transection epinephrine in the ipsilateral hypothalamus was depleted by approximately 60%. Adrenal demedullation had no effect on hypothalamic epinephrine concentrations. It was concluded that hypothalamic epinephrine was central in origin.

Adrenal Medulla↗
PubMed1981

In vivo intraneuronal MAO inhibition in rat brain SKF 64139, comparison to other potent PNMT inhibitors.

SKF 64139, a potent inhibitor of adrenal and brain phenylethanolamine-N-methyltransferase (PNMT), was found to have effects on catecholamines, serotonin and their metabolites in rat brain which suggest it may act as a potent inhibitor of monoamine oxidase (MAO) 'in vivo' after acute administration. Evidence of this was obtained by observing the concurrent elevation of serotonin and depletion of its major metabolite 5-hydroxyindoleacetic acid (5-HIAA), as well as depletion of the dopamine metabolites homovanillic acid and 3,4-dihydroxyphenyl-acetic acid (DOPAC) following acute administration. Additional evidence was obtained by antagonism of the increase in acid metabolites and depletion of amines following treatment with reserpine. Using the depletion of brain DOPAC as an index of MAO activity, an ED50 of 3-4 mg/kg was found for SKF 64139 as an "in vivo' MAO inhibitor.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1981

Alterations in cerebrospinal fluid dopamine metabolites following physostigmine infusion.

The effect of IV physostigmine administration on the cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC) in normal subjects was determined. After an adjustment for differing CSF concentrations of probenecid, physostigmine was found to elevate CSF HVA and DOPAC concentrations. The authors discuss these changes in CSF HVA and DOPAC and their possible relationship to the ability of physostigmine to decrease the symptoms of some patients with tardive dyskinesia.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1981

Cross tolerance between morphine and the long-term analgesic reaction to inescapable shock.

Animals exposed to a variety of stressors display a temporary analgesic reaction. This short-term analgesia has been shown to be reversible by opiate antagonists and cross-tolerant with morphine following some stress conditions, but not following others. It has recently been shown that inescapable shock parameters which produce behavioral '"learned helplessness" effects also produce a short-term analgesic reaction, and that this reaction can be re-aroused by a brief exposure to shock 24 hours later. Further, both the immediate and long-term antinociceptive reaction which follow shocks of this type have been shown to be reversible by opiate antagonists. Here it is shown that the long-term analgesic reaction is completely cross tolerant with morphine. Implications of these results for opioid mediation of learned helplessness and opioid versus nonopioid mediation of stress-induced analgesia are discussed.

Animals↗
PubMed1981

Thermal denaturation of native striatal tyrosine hydroxylase: increased thermolability of the phosphorylated form of the enzyme.

Tyrosine hydroxylase was purified from bovine corpus striatum. The native enzyme had a half-life of 15 +/- 3 min at 50 degrees C. Phosphorylation of tyrosine hydroxylase with protein kinase purified from both corpus striatum and heart activated the enzyme, but activity was rapidly lost with additional preincubation of the enzyme at 30 degrees C. Thermal denaturation studies indicated that phosphorylated tyrosine hydroxylase had a half-life of 5 +/- 2 min at 50 degrees C

Animals↗