Failure of Standards in Reporting the Composition of Artificial Cerebral Spinal Fluid in Studies of the Pial Blood Vessels

To the Editor: Reproducible experimental results require the replication of the experimental conditions under which the experiment was first performed. Relevance to humans may depend on the degree to which those conditions resembled those to which humans are exposed. With respect to studies of vascular reactivity, a most important parameter is the composition of the fluid bathing the vessel. For vessels on the brains surface, so-called pial vessels, this fluid is the cerebrospinal fluid (CSF). Experiments studying these vessel, in vivo or in vitro, generally bathe the vessels in an artificial CSF, sometimes called a “mock” CSF, or some other fluid, sometimes called a physiological salt solution and sometimes simply a buffered solution. A question that should immediately arise, if relevance to humans is an issue, is whether the fluid used has the composition of cerebrospinal fluid, and if so, is it the composition of the experimental species’ CSF or of human CSF. At present there is no data to tell us whether or not it would be better to always replicate the composition of human CSF, even if this differs from that of the animal …