The distribution and intensity of AQP4, AQP1, and GFAP labeling in the hydrocephalic brain of the African grey parrot are summarized in Table 1.
The AQP1 study revealed a marked decrease in the intensity of staining compared with the control brain (Fig 3).
We observed a general correlation in the distribution and intensity of these 2 markers, whereas AQP1 showed less immunolabeling in the hydrocephalic brain than in the control brain.
AQP1 was reported to be selectively expressed in the microvasculature, and AQP2 and AQP3 are commonly expressed in epithelial cells in various organs.
It could be suggested that BOO may activate the NOS system, which regulates AQP1 in capillaries and allows plasma transudation from the capillaries to the subepithelial layer.
Such rapid reabsorption in the PCT and descending loop of Henle is facilitated by a high density of AQP1 and AQP3 (Figure 3A).
6) Although AQP1 has been shown to contain glycosylation corresponding to the ABO system, an AQP 1 deficiency does not affect a person's ABO type.
Many aquaporins are mercury sensitive, and in AQP1
a mercury-sensitive cysteine residue (Cys-189) is present adjacent to a conserved Asn-Pro-Ala motif.
From analysis of the crystal structures of AQP1 and GlpF, it has been proposed that the positive charge of this arginine residue forms an electrostatic triangle with two negatively charged residues to polarize the substrate molecules and to provide a filter that prevents charged molecules from entering the channel.
Structural basis of water-specific transport through the AQP1 water channel.
A thorough understanding of renal physiology now explains the very rapid reabsorption of water in the proximal convoluted tubule (PCT) by acknowledging the presence of plethora of AQP1 channels in the membranes.
As mentioned previously, AQP1 is present in many cells, including red blood cells, and is responsible for the majority of water reabsorbed in the PCT Since approximately 75% of the filtrate is reabsorbed in the PCT, it is surprising that patients with a complete AQP1 deficiency have only a subclinical form of NDI.