Chowdhury P, Soulsby ME, Miller J, Pasley JN, Rayford PL.
Proc Soc Exp Biol Med. 1998 Jul; 218: 263.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock 72205, USA.
Rat tail suspension offers a useful model to reproduce physiologic responses to weightlessness. There is little information reported in the literature describing the disposition of blood-borne particles during weightlessness. This study examines the tissue distribution of 3H-nicotine under the influence of simulated microgravity. Methods: Twelve male rats divided equally into control and experimental groups were used. The experimental group was tail-suspended at 30 degrees for two weeks on a 12/12 LD cycle. Afterward, animals were anesthetized and IV injected with 0.4 ml (4 microCi) of the 3H-nicotine solution. After 90 minutes, the injected animals were sacrificed, exsanguinated, and tissues harvested (brain, blood, trachea, salivary gland, lung, heart, esophagus, liver, fundus, antrum, spleen, pancreas, duodenum, jejunum, colon, adrenals, kidneys. and testes). Tissue samples were homogenized and processed for radioactivity. Tissue counts were corrected for dilution and for background counts. The distribution of (3H) nicotine per gram tissue was calculated as percent of total injected radioactivity. Results: Body weights of suspended animals were significantly lower than those of controls (309 +/- 21 vs. 350 +/- 11 g). The greatest amount of nicotine was retained by the kidneys, followed by the salivary glands, spleen. gastrointestinal tissues, etc. When compared to controls, following tissues from the suspended group appeared to have decreased retention of nicotine [esophagus (25%), aorta (25%), fundus (25%), trachea (22%), adrenals (18%), spleen (17%), and pancreas (12%)], with exception of the testes and salivary gland where the retention was higher by 40% and 16% respectively. Conclusion: The decreased nicotine retention in tissues from suspended animals may reflect fluid shifts and changes in blood flow in those tissue beds. The lack of differences in nicotine retention between control and suspended groups in liver and kidney may reflect normal metabolic activity. Causes for increased nicotine retention by testes and salivary gland from suspended animals are not clear and will require further investigation. Supported by NASA and the Arkansas Space Grant Consortium.
Publication Types:
Keywords:
- Animals
- Arkansas
- Brain
- Hindlimb Suspension
- Kidney
- Liver
- Lung
- Male
- Models, Biological
- Muridae
- Nicotine
- Rats
- Rats, Inbred F344
- Rats, Inbred Strains
- Rats, Sprague-Dawley
- Rats, Wistar
- Salivary Glands
- Spleen
- Tissue Distribution
- Weightlessness
- Weightlessness Simulation
Other ID:
UI: 102237338
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