W C Steinhoff

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The short-term temporal dynamics of phytoplankton composition was compared among coral reef waters, the adjacent ocean and polluted harbour water from July until October along the south-western coast of Curaçao, southern Caribbean. Temporal variations in phytoplankton pigment 'fingerprints' (zeaxanthin, chlorophyll b, 19′-hexanoyloxyfucoxanthin,(More)
The effects of low and high doses of serotonin on tonic immobility (TI) duration and susceptibility in 10- and 45-day-old chickens were examined. High doses of serotonin reduced the number of inductions required to produce TI, regardless of the subject's age. In contrast, low and high doses of serotonin produced biphasic increases and decreases in TI(More)
Histologically and by means of gelatine-Indian ink injections, the development of the coronary circulation was studied in 171 hearts of chicken embryos between 36 hours of incubation and the 2nd day after hatching. In addition, 9 adult hens were examined. In the heart at first a venous circulatory system develops. It consists of 1. intertrabecular spaces(More)
Low doses of serotonin potentiated immobility durations in 2 1/2-week-old chickens (Gallus gallus) while high doses attenuated the response. Cyproheptadine, a serotonergic antagonist, eliminated increases generated by low doses of serotonin and reduced durations in control subjects, but had no effect on the attenuation produced by high doses of the drug.(More)
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