Neurosecretory cells: daily rhythmicity in Leiobunum longipes
Science (New York, N.Y.)
|May 20, 1966
Abstract:
A fluorometric-analysis procedure, used to quantitate indoles, confirmed the presence of 5-hydroxytryptamine (5-HT) in an arachnid; there was unimodal cyclic production of 5-HT in brain and intestinal tissues over a 24-hour period. The same tissues produced 5-HT after 80-day culture; bimodal cyclic output was indicated during continuous 24-hour study. One peak occurred at 0200 hours, at the same time as the peak in vivo, suggesting an endogenously controlled mechanism of secretion. The second peak occurred at midmorning, a time when production in vivo was lowest, suggesting that there is a possible feedback-control mechanism in the organism that inhibits the endogenous output of 5-HT.
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