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Details for article 1 of 11 found articles
| Title: |
Circadian Fluctuation of Catecholamines in the Cockroach Brain-Subesophageal Ganglion Complex detected by HPLC-ECD |
| Author: |
Natsukawa, T. Tanigawa, T. Takeda, M. |
| Appeared in: |
Biological rhythm research |
| Paging: | Volume 27 (1996) nr. 2 pages 138-147 |
| Year: |
1996-05 |
| Contents: |
Fluctuations of catecholamine contents in the cockroach brain-subesophageal ganglion (Br-SG) complex were examined by HPLC with electrochemical detector. The chromatographic system detected dopamine (DA), norepinephrine (NE), epinephrine (EP) and some putative metabolites as standard compounds. Da, NE and EP were detected in the Br-SG complex whereas those metabolites such as 2,5-dihydroxyphenylacetic acid (DOPAC) and 3-methoxy 4-hydroxy phenylglycol (MOPEG) were not detected from the tissue samples in a significant amount. The distribution of DA in the central nervous system was strongly biased toward cephalic ganglia, whereas EP was distributed more evenly over all ganglia. EP existed in both free and conjugated forms, the latter being predominant. Fluctuation patterns of these catecholamines were distinct; DA level kept constant throughout the day, at ca 200 ng/mg protein, NE showed a peak around AZT (artificial Zeitgeber time) 12, i.e., the light-off moment and the rhythm free-ran in constant darkness (DD), and both the free and the conjugated, i.e., acetylsulfate, forms of EP had peaks around mid-dark (AZT 18), in antiphase to the NE peak, and had a trough around AZT 12. Since both forms of EP showed the same fluctuation pattern, EP content in free form was regulated mainly by phenylethanolamine N -methyltransferase (PNMT) but not by hydrolysis of the conjugated EP. Since the enzymatic activities of monoamine oxidase (MAO), catechol O -methyltransferase (COMT) and aldehyde reductase (AR) were low, the fluctuation of these amines must be regulated by N -acetyltransferase (NAT), dopamine ss-hydroxylase (DBH) and PNMT. |
| Publisher: |
Taylor & Francis |
| Source file: |
Elektronische Wetenschappelijke Tijdschriften |
Details for article 1 of 11 found articles
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