San Diego, CA -- Most terrestrial amphibians acquire water by absorption across their skin rather than by oral drinking. During periods of rehydration, frogs and toads adopt a posture termed "water absorption response" (WR), thrusting their hindlimbs backwards and pressing the belly surface on to any surface containing water. In many frog and toad species, such as the Bufo breed, a specific area of the belly skin (the seat patch), is used for absorbing water. Even though the seat patch skin only constitutes about ten percent of the total skin area, it is responsible for over 70 percent of the total water uptake by dehydrated toads. The seat patch skin is equipped with an elaborate capillary network. Interrupting capillary perfusion of isolated skin and in living animals results in a washout of salts from the interstitial fluid of the skin, thereby decreasing the osmotic gradient and the osmotic water flow across the skin. Circulation in the skin of this patch seems vital to this process, yet very few studies have investigated rates of blood flow in the seat patch skin while toads were exhibiting water absorption behavior.
The above story is based on materials provided by American Physiological Society. Note: Materials may be edited for content and length.
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