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Biomedical subjects

J Axelrod

Publications and source records attributed to J Axelrod.

At least 181 records · Page 10Linked to original sources
PubMed1974

Octopamine: presence in single neurons of Aplysia suggests neurotransmitter function.

Octopamine has been identified and measured in individual neurons from Aplysia californica. Neither dopamine nor norepinephrine was detected in these cells. Thus, in Aplysia there may be separate populations of catecholaminergic and monophenolaminergic cells. Octopamine may have functions of its own in the central nervous system of mollusks.

Animals↗
PubMed1974

Pineal beta-adrenergic receptor: diurnal variation in sensitivity.

The responsiveness of the pineal beta-adrenergic receptor that regulates serotonin-N-acetyltransferase activity is nearly ten times greater at the end of the light period (0600 to 1800 hours) than at the end of the dark period (1800 to 0600 hours). These changes in sensitivity of the postsynaptic beta-adrenergic receptor are related to diurnal changes in the release of noradrenaline from sympathetic nerves innervating the pineal. Supersensitivity of the receptor appears to result from decreased release of the neurotransmitter during daytime, and subsensitivity from increased release at night.

Acetyltransferases↗
PubMed1974

Pineal gland: 24-hour rhythm in norepinephrine turnover.

There is a 24-hour rhythm in the turnover of norepinephrine in sympathetic nerves innervating the pineal gland. This rhythm persists in blinded animals but is suppressed in normnal rats by light. The rhythm in norepinephrine turnover generates the rhythums in pineal indoleamines and N-acetyltransferase.

Acetyltransferases↗
PubMed1974

Amphetamine in human plasma: a sensitive and specific enzymatic assay.

A sensitive and specific enzymatic-isotopic method of determining plasma amphetamine concentrations in man is described. The assay is based on the transfer of the tritiated methyl group of S-adenosyl-L-[methyl-(3)H]methionine to amphetamine in the presence of a partially purified N-methyltransferase from rabbit lung. With this assay as little as 10 nanograms of amphetamine per milliliter of plasma can be accurately determined. The concentrations of d- and 1-amphetamine in the plasma after 20 to 30 milligrams of the drug had been ingested by human subjects are reported.

Amphetamine↗
PubMed1974

Coexistence of several putative neurotransmitters in single identified neurons of Aplysia.

By sensitive enzymatic micromethods several putative neurotransmitters were measured in four identifiable neurons of Aplysia californica (R-2, R-14, L-11, and C-1). Serotonin was found in all of these neurons, and octopamine in all but C-1. Acetylcholine has been previously reported to be present in R-2 and L-11. The catecholamines, norepinephrine and dopamine, were not detected in the four cells examined. The possible biological consequence of the presence of several putative transmitters in single identifiable neurons is discussed.

Animals↗
PubMed1974

Characterization and substrate specificity of a protein carboxymethylase in the pituitary gland.

Protein carboxymethylase, an enzyme capable of methylating proteins and polypeptides, was purified from bovine pituitary. The anterior pituitary hormones, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone, growth hormone, thyroid-stimulating hormone, and prolactin, were found to be substrates for this enzyme. The posterior pituitary hormones, oxytocin and vasopressin, did not serve as substrates. With luteinizing hormone as the substrate, protein carboxymethylase had a pH optimum near pH 5.5. A limiting K(m) of 1.47 muM for S-adenosyl-L-methionine was obtained with luteinizing hormone as the methyl acceptor. Possible roles of this enzyme in the posterior and anterior pituitary are discussed.

Adrenocorticotropic Hormone↗
PubMed1974

Association between fighting behavior and catecholamine biosynthetic enzyme activity in two inbred mouse sublines.

Levels of three adrenal catecholamine synthesizing enzymes and isolation-induced fighting behavior were studied in two related sublines of the Balb/c inbred mouse strain. Enzyme levels were twice as high in the adrenals of Balb/cJ mice as in those of the Balb/cN mice; heterozygous progeny were intermediate between their parents in the levels of the three enzymes. These sublines also showed marked differences in their fighting behavior after a 2-week isolation period. Balb/cJ mice fought immediately after presentation of an intruder mouse, while Balb/cN mice did not fight at any time during the test. Heterozygous progeny behaved more like the Balb/cN (non-fighters). Analysis of F(2) mice suggested that the differences in fighting behavior were determined by a single gene, with fighting being recessive.

Adrenal Glands↗