Cerebral water channels - aquaporins

Water channels (aquaporins) are integral proteins of plasmatic membranes, subserving selective water transport. Out of the whole family of these proteins, which so far includes eleven members, two are most significant for brain processes and regulation mechanisms: aquaporin 1 (AQP1) and aquaporin 4 (AQP4). Whereas AQP1 apparently significantly influences cerebrospinal fluid secretion, the role of AQP4 in the brain is far more complex. Results of experimental studies in laboratory rodents in the last ten years have shown that AQP4 has effects on potassium and body fluid homeostasis, influences central osmoreception, participates in parasynaptic communication and plays a significant role in the generation of cerebral edema. The properties of cerebral aquaporins recognized so far elucidate several states that the neurosurgeon not infrequently faces. These include cerebrospinal fluid dynamics, hyponatremic syndromes and cerebral edema.