Gastrointestinal (GI) function plays a critical role in the absorption and bioavailability of orally administered drugs. Further, the GI tract plays a pivotal role in the bioavailability of nutrients. The availability of energy depends on intake, absorption, storage, and utilization. The absorption and bioavailability of ingested compounds depend on physiological factors such as GI motility, splanchnic blood flow, and pH of gastric secretions.
Negative nutrient balance directly affects the energy level of an individual which in turn decreases motivation and cognitive ability. The purpose of this study is to further validate the Automated Neuropsychological Assessment Metric (ANAM) Readiness Evaluation System (ARES) software for the space program.
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GI motility governs the time needed for food to travel from the mouth to the cecum. Motility, itself, is influenced by fluid intake, body position, gravity, food composition, individuals' activity, and a number of other conditions. Prolonged bed rest, like space flight, will influence all of the aforementioned factors. Hypokinesia, associated with bed rest has been shown to induce loss of appetite, constipation, and indigestion, all of which can be attributed to changes in gastric function. Further, Russian reports suggest that these symptoms are very similar to those seen by their cosmonauts during space missions. This suppression in appetite will lead to negative nutrient balance thus causing a change in energy level and cognitive function.
Cognitive measures were collected using the ARES hand held cognitive function test. The validation of both ARES and Windows based cognitive assessment tool (WinSCAT) has been done in several studies. Previous results from the Johnson Space Center Pharmacology Lab assessing cognitive function have shown a similar effect with both WinSCAT and ARES. Subjects administered promethazine have shown similar decrements in peak response time (40 milliseconds using WinSCAT and 60 milliseconds using the ARES) as compared to baseline response time.
This experiment has concluded in ground-based studies sponsored by the National Aeronautics and Space Administration's Human Adaptation and Countermeasures Division. This experiment was conducted during Bed Rest Campaigns 1 and 3A. LSDA doesn't expect to receive results from this study.