Revista Chilena de Historia Natural 81 (1): 33-40, 2008
RESEARCH ARTICLE
Distribution of aquaporins in the nasal passage of Octodon degus, a South-
American desert rodent and its implications for water conservation
Rodents from arid and semiarid environments live under conditions where the spatial and
temporal availability of water is limited. Octodon degus is a South-American desert dwelling rodent inhabiting arid and
semiarid habitats of central and northern Chile. Its survival depends on morphological, physiological and behavioral adaptations that
allow water conservation. This rodent has a high urine concentrating ability, high capacity of fecal dehydration and low evaporative
water loss, related to the ability of the nasal passages to condense water from the exhaled air; this water must be absorbed in order to
avoid its accumulation in the nasal passages and potential loss through the nostrils. We hypothesize that aquaporins (AQPs) might be
present in the nasal mucosa; therefore, we studied the distribution of AQP-1, AQP-2, AQP-3 and AQP-4 through
immunocytochemistry. Intense AQP-1 labeling was observed throughout the subepithelial vascular network; no AQP-1
immunoreactivity was detected in olfactory and non-olfactory epithelial cells. No signal was detected for AQP-2 and 4. AQP-3
distribution was restricted to the surface non-olfactory epithelial cells lining the turbinates in narrow passages and blind spaces.
Therefore, AQP-1 and AQP-3 coincided at the level of the turbinates, although in different cell types which suggest a pathway for water
removal from the nasal surface first through AQP-3 in non-olfactory epithelial cells and then into the capillary lumen through AQP-
1.
Key words:
aquaporin, nasal
passage, desert rodent
