ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Fluorometric measurements were made of 5-hydroxytryptamine levels in spleens obtained from separate subgroups of adult male rats killed at two-hourly intervals over four separate 24-hour time spans. For three weeks prior to obtaining tissue, all rats were standardized carefully and were subjected to 12 hours of light (0600-1800) followed by 12 hours of darkness. Analyses showed in each study very significant fluctuation over the 24-hour time scale; the range of change over this period was as great as 131%. The phasing of the rhythms, in spite of the rigid environmental synchronization, was not similar in any of the four studies. Possible explanations for this unexpected desynchronization are discussed. Spleen weights also fluctuated with a significant 24-hour circadian frequency.In addition, the rhythm characterizing this amine was described in female rats as well as the effect of different stimuli on the same rhythm. These stimuli were ether, immobilization and a ‘novelty’ situation; and all three significantly increased the levels of 5-HT in spleen when the overall 24-hour mean values of each experimental group were compared with controls. However, in all cases there were discrete time points when significant differences in 5-HT levels could not be obtained with any of the stimuli. This study demonstrates that the effect of the stimuli used depends on the phase of the rat's circadian system during which it was applied. The necessity of considering the natural rhythmic fluctuation in any investigation evaluating this biogenic amine in spleen is demonstrated.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091730302
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