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Eddy-covariance and biometeorological methods show significant net annual carbon uptake in an old-growth Douglas-fir 64 forest in southwestern Washington, USA. These results contrast with previous assumptions that old-growth forest ecosystems are in carbon equilibrium. The basis for differences between conventional biomass-based carbon sequestration(More)
The purpose of this study was to test the capacity of different visible wavelengths of light to suppress nocturnal levels of pineal melatonin in hamsters. It was found that the visible wavelengths vary in their ability to perturb pineal melatonin. During the period of peak pineal melatonin production, animals were exposed to fluorescent light sources having(More)
A stereological analysis was made of synapses in the left and right hemispheres of chick medial hyperstriatum ventrale (MHV) 24h after passive avoidance training (PAL) and in water trained controls (W-control). The synaptic parameters examined were (D), the mean length of the postsynaptic thickening; (NV.syn), the number of synapses per unit volume of(More)
Serotonin and 5-hydroxyindoleacetic acid were measured in the pineal gland of Syrian hamsters by high performance liquid chromatography over a period of 24 h. A distinct 24 h rhythm was detected for both indoles. Turnover studies revealed a higher rate of serotonin synthesis during the day than during the night. We therefore suggest that the serotonin(More)
The formation of pineal 'synaptic' ribbons (SR) may be directly related to the adrenergic innervation of the gland. In order to clarify this relationship, SR populations at various times from 12 h to 14 days after pineal denervation were morphometrically analysed by electron microscopy. Pineal denervation was accomplished by bilateral superior cervical(More)
The number of "synaptic" ribbons was inversely correlated with the density of the adrenergic nerve endings of the pineal gland compared among a diverse group of species including the fox, cat, rat, cotton rat, white-footed mouse, Djungarian hamster, ground squirrel, and chipmunk. The concentration of norepinephrine paralleled the number of adrenergic nerve(More)
The dense-core vesicles and 'synaptic' ribbons were counted in Djungarian hamster pinealocytes after superior cervical ganglionectomy. Sympathectomy caused a decrease in the number of dense-core vesicles in pinealocytes, suggesting diminished secretory activity of these cells. An increase in the number of 'synaptic' ribbons after superior cervical(More)
The ultrastructure of pinealocytes was examined morphometrically in superior cervical ganglionectomized and sham-operated cotton rats. Following denervation, the pinealocytes decreased in size. Reduced areas of the nucleoli, Golgi apparatus, granular endoplasmic reticulum, mitochondria, and vacuoles containing a flocculent material as well as a decreased(More)
Pineal N-acetyltransferase (NAT) activity and radioimmunoassayable levels of melatonin were compared in 2-month-old (young), 12-month-old (middle-aged), and 29-month-old (old) female rats killed at 1600 h (during the light) and at 2300 h (4 h after darkness onset) and 0100 h (6 h after darkness onset). During the light period, NAT levels were equivalent in(More)
Pineal melatonin levels were compared in laboratory-raised or wild-captured 13-lined ground squirrels (Spermophilus tridecemlineatus) that were either exposed to 10 h of darkness at night or to light which had an irradiance of 400 microW/cm2. In laboratory-born squirrels the period of darkness was associated with a gradual rise in pineal melatonin levels(More)