A peer-reviewed tissue study compares the stomachs of hibernating and active Anatolian ground squirrels. Hibernation was associated with smaller stomach dimensions and region-specific changes in wall layers and cell features. Microscopy also found differences in gland structures and cell-proliferation markers. How those structural changes affect digestion remains unresolved, and the findings cannot be generalized directly to humans.
Anatolian ground squirrels had smaller, contracted stomachs during hibernation than during their active period. A single peer-reviewed anatomical and tissue study at Erciyes University in Turkey compared the two physiological states. Hibernating stomachs contained no visible ingested material. The animals’ stomachs have one compartment, with two distinct subregions within the main body of the organ.[1]
Researchers examined gross organ structure with stereo microscopy, tissues with light microscopy and the internal surface with scanning electron microscopy. Changes in stomach-wall thickness differed between regions. Gland dimensions and the sizes of surface, acid-secreting and principal cells also varied. Special stains traced the distribution and intensity of mucus substances rather than directly measuring the rate of digestion.[1]
Tests of a neuron-associated protein revealed differences in intestinal nerve networks between the two states. A cell-proliferation marker was seen less often during hibernation, with positive nuclei concentrated around the gland necks. That assessment was qualitative. Structural observations describe this species’ stomach; physiological and molecular experiments are still needed to determine their meaning for digestive and secretory function.[1]
